UNITED STATES CRYPTOLOGIC HISTORY

Sources in

Cryptologic History

Number 3

The Friedman Legacy:

A Tribute to

William and Elizebeth Friedman

Third Printing

CENTER FOR CRYPTOLOGIC HISTORY

NATIONAL SECURITY AGENCY

2006

Page iii

Table of Contents

Page

Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

by David Gaddy

Biographical Sketch, William F. Friedman . . . . . . . . . . . . . . . . . . . . . . vii

“Six Lectures on Cryptology” 

by William F. Friedman . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

by Frank Rowlett

Lecture I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Introduction

Lecture II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

The earliest attempts at cryptography, from the invention of the art

of writing to Bacon’s “Bi-literarie” cipher.

Lecture III . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

The cryptosystems used by the British Regulars and by the Colonials 

during the period of the American Revolution. This is followed by a

brief explanation of the cryptanalytic nature of the initial breaks in the

solution of the ancient Egyptian hieroglyphic writing.

Lecture IV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55

Cryptology in the Civil War.

Lecture V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91

Cryptology from the end of the Civil War to the end of World War I.

Lecture VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .133

Cryptology from the end of World War I to the end of World War II. 

The emphasis has been placed upon communications security (COMSEC), not only because in five preceding lectures the emphasis was

placed very largely upon communications intelligence (COMINT), but
also because, in the final analysis, COMSEC, though not as spectacular

as COMINT, is really more vital to national security.

Appendix I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .173

Appendix II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .177

Bibliography [for Friedman lectures] . . . . . . . . . . . . . . . . . . . . . . . .183

“The Legendary William F. Friedman”

by Lambros Callimahos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .185

“Breaking Codes Was This Couple’s Lifetime Career”

by James R. Chiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .195

In Memoriam: Elizebeth Smith Friedman

 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .205

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .209

Page iv
To term this modest collection The Friedman

Legacy requires both explanation and apologia. Of

Friedman, as of Wren, it might well be said, “If you

seek his monument, look around you” at the giant

and far-flung corporate entity that represents

American cryptology today. But a most tangible and

rewarding form of his legacy for many of us has

long been his “Lectures.” First published within

NSA in 1963, after serialization in a journal five

years earlier, they were republished two years 

later by his first recruit into government service 

and the first commandant of the National

Cryptologic School, the eminent cryptologist Frank

Rowlett. In his Foreword to that edition, Mr.

Rowlett described the lectures as “. . . the history of

Cryptology [as] recorded by the most prominent

pioneer in the application of scientific principles to

the field – one who, without question, laid the foundation for our modern concepts. It is hoped that

both new and old employees may be inspired with a

feeling of belonging to a profession that abounds in

drama and fascination and that has had a profound

impact on history.”

The sense of what one might term “the romance

of cryptology” continues to adhere: Director Vice

Admiral W.O. Studeman, introducing the 1990

Cryptologic History Symposium in NSA’s William

F. Friedman Auditorium, referred affectionately

and with a hint of awe to “this magical [MAGIC-al?]

place.” That mystique, derived from an appreciation of the privilege of service to the nation in a

largely anonymous but most rewarding profession,

in company with a rare breed of men and women,

must be rediscovered with each new generation. As

tools and techniques become less personal, as individual accomplishment is more difficult to discern,

it comes to depend increasingly on awareness of the

past – the heritage, the traditions, the symbols, of

the Friedman era, when a tiny unit of Army civilians and their uniformed Navy counterparts began

a revolution – and the ability to find equally satisfactory modern equivalents, to become part of a

continuum.

In making The Friedman Lectures again available to the professional community, several related

papers have been included to give the newcomer a

fuller appreciation of Friedman and his fellow

cryptanalyst and lifemate, Elizebeth: the recollections of his colleague and amanuensis, Lambros

Callimahos, Guru and Caudillo of the Dundee

Society (parochial humor that must be separately

explained to the newcomer), a tribute to Elizebeth

on the occasion of her death, and an appreciation of

the two from a fellow laborer in the vineyard –

these, with the Lectures, we have been bold to style

The Friedman Legacy.

David W. Gaddy

Chief

Center For Cryptologic History

[1992]

Page v

Foreword

Page vii

WILLIAM FREDERICK FRIEDMAN (1891-

1969), the dean of modern American cryptologists,

was the most eminent pioneer in the application of

scientific principles to cryptology and laid the foundation for present-day cryptologic concepts. Born

in Kishinev, Russia, on 24 September 1891, he was

brought to the United States in 1892; married

Elizebeth Smith in May 1917; fathered a son, John,

and a daughter, Barbara. He retired from the

National Security Agency in 1955 after thirty-five

years of service with U.S. cryptologic activities. Mr.

Friedman died at his home in Washington, D.C., on

2 November 1969.

B.S. (genetics), Cornell University, 1914;

Research Fellow, New York State Experiment

Station, Geneva, N.Y., 1914; Graduate Student and

Instructor in Genetics, Cornell University, 1914-

1915; Director, Department of Genetics, Riverbank

Laboratories, Geneva, Ill., 1915-1916; Director,

Departments of Ciphers and Genetics, Riverbank

Laboratories, 1916-1918; 1st lieutenant, serving in

Code and Cipher Solving Section, G-2, General

Headquarters, American Expeditionary Forces

(GHQ AEF), Chaumont, France, 1918-1919 (retired

as lieutenant vcolonel, USAR, 1951); Director,

Department of Ciphers, Riverbank Laboratories,

1919-1920; Cryptographer, Office of the Chief

Signal Officer (OCSigO), Washington, D.C., 1921;

Chief Cryptographer, U.S. Signal Corps, 1922-1929;

Cryptanalyst, War Department, 1930-1942;

Director, Communications Research, Signal

Intelligence Service, later Army Security Agency,

1942-1947; Chief, Communications Research

Section, Army Security Agency, 1947-1949;

Cryptologic Consultant, Army Security Agency,

1949; Research Consultant, Armed Forces Security

Agency, 1949-1951; Research Consultant, National

Security Agency, 1951-1954; Special Assistant to the

Director, NSA, 1954-1955 (retirement); Member,

NSA Scientific Advisory Board, 1954-1969; Special

Consultant, National Security Agency, 1955-1969.

Biographical Sketch
Page viii

For his many contributions to the security of his

country, he received the War Department Medal

for Exceptional Civilian Service (1944), the

Presidential Medal for Merit (1946), the

Presidential National Security Medal (1955), and a

special congressional award of $100,000 for inventions and patent in the field of cryptology (1956).

For their contributions to literature, he and Mrs.

Friedman received the Fifth Annual Shakespeare

Award in 1958 from the American Shakespeare

Festival Theater and Academy for their book The

Shakespearean Ciphers Examined.

Mr. Friedman was a member of Sigma Xi, the

Cosmos Club, the U.S. Naval Institute, and the

Shakespeare Association of America. He was listed

in Who’s Who in America and American Men of

Science.

Author of many classified books and brochures,

technical treatises and articles on cryptologic subjects; articles in the Signal Corps Bulletin (1925-

1940); Riverbank Publications on Cryptology

(1918-1922), the more important of which are

“Several Machine Ciphers and their Solution,” “The

Index of Coincidence and Its Applications to

Cryptography,” and “Applications of the Science

of Statistics to Cryptography,” Elements of

Cryptanalysis (1923); technical papers and reports

published by the Office of the Chief Signal Officer

and by the Signal Intelligence Service (1935-1945),

among which may be mentioned “The Principles of

Indirect Symmetry of Position in Secondary

Alphabets and their Application in the Solution of

Polyalphabetic Substitution Ciphers,” “American

Army Field Codes in the American Expeditionary

Forces in the First World War” (1942); “Field Codes

used by the German Army during the World

War,” and “Analysis of a Mechanico-Electrical

Cryptograph”; Encyclopedia Britannica article

“Codes and Ciphers (Cryptology),” 1927 (revised

1954); Military Cryptanalytics, Parts I & II (with L.

Callimahos); “The Cryptologist Looks at

Shakespeare”; The Shakespearean Ciphers

Examined, coauthor with his wife Elizebeth Smith

Friedman (Folger Shakespeare Prize, 1955);

“Acrostics, Anagrams, and Chaucer,” Philological

Quarterly, 1959; “Jacques Casanova, Cryptologist,”

in Casanova Gleanings, Nice, France, 1961.
William & Elizebeth

The Riverbank

Years

William & Elizebeth

The Later Years

The Friedman home in Washington, DC

Six Lectures on Cryptology

by

William F. Friedman
Page 2

These six lectures by Mr. William F. Friedman,

dean of American cryptologists, were prepared in

order to have the history of cryptology recorded by

the most eminent pioneer in the application of scientific principles to the field – one who, without

question, laid the foundation for our modern concepts. It is hoped that both new and old employees 

may be inspired with a feeling of belonging to a profession that abounds in drama and fascination and

that has had a profound impact on history. The lectures, published for the first time in 1963,* are now

[1965] being reprinted to meet a continuing

demand for an authoritative history of our craft.

Frank B. Rowlett

Commandant, National Cryptologic School

* Editor’s Note: The Friedman lectures were

also serialized in the NSA Technical Journal from

1959 to 1961.

Foreword
Page 3

The objective of this series of lectures is to create an awareness of the background, development, and manner of employment of a science

that is the basis of a vital military offensive and

defensive weapon known as CRYPTOLOGY, a

word that comes from the Greek kryptos, meaning secret or hidden, plus logos, meaning knowledge or learning. Cryptology will be specifically

defined a little later; at the moment, however, I’m

sure you know that it has to do with secret communications.

Let me say at the outset of these lectures that

I may from time to time touch upon matters that

are perhaps essentially peripheral or even irrelevant to the main issues, and if a defense is needed

for such occasional browsing along the byways of

the subject, it will be that long preoccupation with

any field of knowledge begets a curiosity, the satisfaction of which is what distinguishes the dedicated professional from the person who merely

works just to gain a livelihood in whatever field he

happens to find himself a job. That’s not much

fun, I’m afraid. By the way, a British writer, James

Agate, defines a professional as the man who can

do his job even when he doesn’t feel like doing it;

an amateur as a man who can’t do his job even

when he does feel like doing it. This is pretty

tough on the gifted amateur, and I for one won’t

go all the way with Agate’s definition. There are

plenty of instances where gifted amateurs have

done and discovered things to the chagrin and

red-facedness of the professionals.

Coming back now to the main thoroughfare

after the foregoing brief jaunt along a byway, I

may well begin by telling you that the science of

cryptology has not always been regarded as a vital

military offensive and defensive weapon, or even

as a weapon in the first place. Here I am reminded of a story in a very old book on cryptography.

The story is probably apocryphal, but it’s a bit

amusing, and I give it for what it’s worth.

It seems that about two thousand years ago

there lived a Persian queen named Semiramis,

who took an active interest in cryptology. She was

in some respects an extraordinarily unpleasant

woman, and we learn without surprise that she

met with an untimely death. She left behind her

instructions that her earthly remains were to be

placed in a golden sarcophagus within an imposing mausoleum, on the outside of which, on its

front stone wall, there was to be graven a message, saying 

Stay, weary traveller! If thou art footsore, hungry, or in need of money -

Unlock the riddle of the cipher graven

below, And thou wilt be led to riches

beyond all dreams of avarice! 

Below this curious inscription was a cryptogram, a jumble of letters without meaning or

even pronounceability. For several hundred years

the possibility of sudden wealth served as allure to

many experts who tried very hard to decipher the

cryptogram. They were all without success, until

one day there appeared on the scene a longhaired, bewhiskered, and bespectacled savant

who after working at the project for a considerable length of time, solved the cipher, which gave

him detailed instructions for finding a secret

entry into the tomb. When he got inside, he found

an instruction to open the sarcophagus, but he

had to solve several more cryptograms, the last

one of which may have involved finding the correct combination to a five-tumbler combination

lock – who knows? Well, he solved that one too,

after a lot of work, and this enabled him to open

the sarcophagus, inside which he found a box. In

Lecture I
Page 4

the box was a message, this time in plain language, and this is what it said: 

O, thou vile and insatiable monster! To

disturb these poor bones!

If thou hast learned something more

useful than the art of deciphering,

Thou wouldst not be footsore, hungry, or

in need of money!

I’m frank to confess that many times during

my forty-year preoccupation with cryptology, and

generally near the middle and the end of each

month, I have felt that good old Queen Semiramis

knew what she was talking about. However, earning money is only a part of the recompense for

working in the cryptologic field, and I hope that

most of you will find out sooner or later what

some of these other recompenses are, and what

they can mean to you.

If Queen Semiramis thought there are other

things to learn that are more useful than the art of

deciphering, I suppose we’d have to agree, but we

are warranted in saying, at least, that there isn’t

any question about the importance of the role

that cryptology plays in modern times: all of us

are influenced and affected by it, as I hope to

show you in a few minutes.

I shall begin by reading from a source you’ll

all recognize – Time, the issue of 17 December

1945. I will preface the reading by reminding you

that by that date World War II was all over – or at

least V-E and V-J days had been celebrated some

months before. Some of you may be old enough to

remember very clearly the loud clamor on the

part of certain vociferous members of Congress,

who had for years been insisting upon learning

the reasons why we had been caught by surprise

in such a disastrous defeat as the Japanese had

inflicted upon us at Pearl Harbor. This clamor

had to be met, for these congressmen contended

that the truth could no longer be hushed up or

held back because of an alleged continuing need

for military secrecy, as claimed by the administration and by many Democratic senators and

representatives. The war was over – wasn’t it? –

Republican senators and representatives insisted.

There had been investigations – a half dozen of

them – but all except one were TOP SECRET. The

Republicans wanted – and at last they got what

they desired – a grand finale joint congressional

investigation that would all be completely open to

the public. No more secrets! It was spectacular.

Not only did the congressional inquiry bring into

the open every detail and exhibit uncovered by its

own lengthy hearings, but it also disclosed to

America and to the whole world everything that

had been said and shown at all the previous Army

and Navy investigations. Most of the information

that was thus disclosed had been, and much of it

still was, TOP SECRET; yet all of these precious

secrets became matters of public information as a

result of the congressional investigation.

There came a day in the congressional hearings when the Chief of Staff of the United States

Army at the time of the Pearl Harbor attack, fivestar general George C. Marshall, was called to the

witness stand. He testified for several long, long

days, eight of them in all. Toward the end of the

second day of his ordeal, he was questioned about

a letter it had been rumored he’d written to

Governor Dewey in the autumn of 1944 during

the presidential campaign. The letter was about

codes. With frozen face, General Marshall balked

at disclosing the whole letter. He pleaded most

earnestly with the committee not to force him to

disclose certain of its contents, but to no avail. He

had to bow to the will of the majority of the committee. I shall now read from Time a bit of information that may be new to many of my listeners,

especially to those who were too young in

December 1945 to be delving into periodical literature or to be reading any pages of the daily newspaper other than those on which the comics

appear.

Said Time:
Page 5

U.S. citizens discovered last week that

perhaps their most potent secret

weapon of World War II was not radar,

not the VT fuse, not the atom bomb, but

a harmless little machine which cryptographers had painstakingly constructed

in a hidden room in Washington. With

this machine, built after years of trial

and error, of inference and deduction,

cryptographers had duplicated the

decoding devices used in Tokyo.

Testimony before the Pearl Harbor

Committee had already shown that the

machine, known as ‘Magic’, was in use

long before December 7,1941, and had

given ample warning of the Jap’s sneak

attack, if only U.S. brass hats had been

smart enough to realize it. Now, General

Marshall continued the story of

“Magic’s” magic:

1. It had enabled a relatively small U.S.

Force to intercept a Jap invasion fleet,

win a decisive victory in the Battle of the

Coral Sea, thus saving Australia and New

Zealand.

2. It had directed U.S. submarines

unerringly to the sea lanes where

Japanese convoys would be passing.

3. It had given the U.S. full advance

information on the size of the Jap forces

advancing on Midway, enabled our Navy

to concentrate ships which otherwise

might have been 3,000 miles away, thus

set up an ambush which proved to the

the turning-point victory of the Pacific

war.

4. By decoding messages from Japan’s

Ambassador Oshima in Berlin, often

reporting interviews with Hitler, it had

given our forces invaluable information

on German war plans.

Time goes on to give more details of that

story, to which I may later return, but I can’t leave

this citation of what cryptology did toward our

winning of World War II without telling you that

the account given by Time of the achievements of

Magic makes it appear that all the secret intelligence gained from our reading Japanese messages was obtained by using that “harmless little

machine” that Time said was used in Tokyo by the

Japanese Foreign Office. I must correct that error

by explaining first that Magic was not the name

of the machine but a term used to describe the

intelligence material to which the machine,

among other sources, contributes and then by

telling you that the secret information we

obtained that way had little to do with those portions of the Magic material that enabled our 

navy to win such spectacular battles as those 

of the Coral Sea and Midway, and to waylay

Japanese convoys. The naval parts of Magic were

nearly all obtained from Japanese naval 

messages by our own very ingenious U.S. Navy

cryptanalysts. At that time, I may tell those of you

who are new, the army and navy had separate but

cooperating cryptologic agencies and activities;

the United States Air Force was not yet in existence as an autonomous and separate component

of the armed forces; and work on Japanese,

German, and Italian air force communications

was done by army cryptanalysts, admirably

assisted by personnel of what was then known as

the Army Air Corps. 

It is hardly necessary to tell you how carefully

the Magic of World War II was guarded before,

during, and after the war until the congressional

inquiry brought most of it out in the open. Some

remaining parts of it are still very carefully guarded. Even the fact of the existence of Magic was

known to only a very few persons at the time of

Pearl Harbor – and that is an important element

in any attempt to explain why we were caught by

surprise by the Japanese at Pearl Harbor in a devastating attack that crippled our navy for many

months. Let me read a bit from page 261 of the

Report of the Majority of the Joint Congressional

Investigation of the attack:
Page 6

The Magic intelligence was pre-eminently important and the necessity for keeping it confidential cannot be overestimated. However, so closely held and top

secret was this intelligence that it

appears that the fact that the Japanese

codes had been broken was regarded as

of more importance than the information obtained from decoded traffic.

Time says, in connection with this phase of

the story of Magic during World War II:

So priceless a possession was Magic that

the U.S. high command lived in constant

fear that the Japs would discover the

secret, change their code machinery,

force U.S. cryptographers to start all

over again.

Now I don’t want to overemphasize the

importance of communications intelligence in

World War II, but I think it warranted to read a

bit more of what is said about its importance in

the Report of the Majority. The following is from

p. 232:

. . . all witnesses familiar with Magic

material throughout the war have testified that it contributed enormously to

the defeat of the enemy, greatly shortened the war, and saved many thousands of lives.

General Chamberlin, who was General

MacArthur’s operations officer, or G-3, throughout the war in the Pacific, has written: “The information G-2, that is, the intelligence staff, gave me

in the Pacific Theater alone saved us many thousands of lives and shortened the war by no less

than two years.” We can’t put a dollars-and-cents

value on what our possession of COMINT meant

in the way of saving lives; but we can make a dollars-and-cents estimate of what communications

intelligence meant by shortening the war by two

years, and the result of that estimate is that it

appears that $1.00 spent for that sort of intelligence was worth $1,000 spent for other military

activities and materials. 

In short, when our commanders had that 

kind of intelligence in World War II, they were

able to put what small forces they had at the right

place, at the right time. But when they didn’t have

it – and this happened, too – their forces often

took a beating. Later on we’ll note instances of

each type.

I hope I’ve not tried your patience by such a

lengthy preface to the real substance of this series

of lectures; let’s get down to brass tacks. For those

of you who come to the subject of cryptology for

the first time, a few definitions will be useful, in

order that what I shall be talking about may be

understood without question. Agreement on

basic terminology is always desirable in tackling

any new subject. In giving you the definitions,

there may be a bit of repetition because we shall

be looking at the same terms from somewhat different angles.

First, then, what is cryptology? Briefly, we

may define it as the doctrine, theory, or branch of

knowledge that treats of hidden, disguised, or

secret communications. You won’t find the

word in a small dictionary. Even Webster’s

Unabridged defines it merely as “secret or enigmatical language”; and in its “Addenda Section,”

which presumably contains new or recently

coined words, it is defined merely as “the study of

cryptography.” Neither of these definitions is

broad or specific enough for those who are going

to delve somewhat deeply into this science.

Cryptology has two main branches: the first is

cryptography or, very briefly, the science of

preparing secret communications and the second

is cryptanalysis or the science of solving secret

communications. Let’s take up cryptography first,

because as a procedure it logically precedes cryptanalysis: before solving anything, there must be

something to solve.
Page 7

Cryptography is that branch of cryptology

that deals with the various means, methods,

devices, and machines for converting messages in

ordinary, or what we call plain language, into

secret language, or what we call cryptograms.

Here’s a picture of one of the most famous cryptograms in history. (See fig. 1.) It was the solution

of this cryptogram that resulted in bringing

America into World War I on the side of the Allies

on 6 April 1917 ,just about six weeks after it was

solved. I’ll tell you about it later in this series. 

Cryptography also includes the business of

reconverting the cryptograms into their original

plain-language form, by a direct reversal of the

steps followed in the original transformation.

This implies that the persons involved in both of

these bits of business, those at the enciphering

and sending end, and those at the receiving and

deciphering end, have an understanding of what

procedures, devices, and so on, will be used and

exactly how – down to the very last detail. The

what and the how of the business constitutes

what is generally referred to as the key. The key

may consist of a set of rules, alphabets, procedures, and so on; it may also consist of an ordinary book that is used as a source of keys; or it

may be a specialized book, called a codebook.

That cryptogram I just showed you was made by

using a book – a German codebook.

To encrypt is to convert or transform a plaintext message into a cryptogram by following 

certain rules, steps, or processes constituting the

key or keys and agreed upon in advance by the

correspondents, or furnished them by higher

authority.

To decrypt is to reconvert or to transform a

cryptogram into the original equivalent plaintext

message by a direct reversal of the encrypting

process, that is, by applying to the cryptogram the

key or keys, usually in a reverse order, employed

in producing it.

A person who encrypts and decrypts messages by having in his possession the necessary

keys is called a cryptographer or a cryptographic clerk.

Encrypting and decrypting are accomplished

by means collectively designated as codes and

ciphers. Such means are used for either or both of

two purposes: (1) secrecy and (2) economy.

Secrecy usually is far more important in diplomatic and military cryptography than economy,

but it is possible to combine secrecy and economy

in a single system. Persons technically unacquainted with cryptology often talk about "cipher

codes,” a term that I suppose came into use to differentiate the term "code" as used in cryptology

from the connotations, for example, the

Napoleonic Code, a traffic code, a building code, a

code of ethics, and so on. Now, in cryptology,

there is no such thing as a “cipher code.” There

are codes and there are ciphers, and we might as

well learn right off the differences between them,

so that we get them straightened out in our minds

before proceeding further.

Fig. 1 The Zimmermann Telegram
Page 8

In ciphers, or in cipher systems, cryptograms

are produced by applying the cryptographic treatment to individual letters of the plaintext messages, whereas in codes or in code systems, cryptograms are produced by applying the cryptographic treatment generally to entire words,

phrases, and sentences of the plaintext messages.

More specialized meanings of the terms will be

explained in detail later, but in a moment I'll

show you an example of a cryptogram in cipher

and one in code.

A cryptogram produced by means of a cipher

system is said to be in cipher and is called a cipher

message, or sometimes simply a cipher. The act

or operation of encrypting a cipher message is

called enciphering, and the enciphered version of

the plain text, as well as the act or process itself, is

often referred to as the encipherment. A cryptographic clerk who performs the process serves as

an encipherer. The corresponding terms applicable to the decrypting cipher messages are deciphering, decipherment, decipherer.

A cryptogram produced by means of a code

system is said to be in code and is called a code

message. The text of the cryptogram is referred to

as code text. This act or operation of encrypting is

called encoding, and the encoded version of the

plain text, as well as the act or process itself, is

referred to as the encodement. The clerk who performs the process serves as an encoder. The corresponding terms applicable to the decrypting of

code messages are decoding, decodement, and

decoder. A clerk who encodes and decodes messages by having in his possession the pertinent

codebooks is called a code clerk.

Technically, there are only two distinctly different types of treatment that may be applied to

written plain text to convert it into a cipher, yielding two different classes of ciphers. In the first,

called transposition, the letters of the plain text

retain their original identities and merely undergo some change in the relative positions, with the

result that the original text becomes unintelligible. Here’s an authentic example of a

transposition cipher; I call it authentic because it

was sent to President Roosevelt, and the Secret

Service asked me to decipher it (fig. 2). Imagine

my chagrin when I had to report that it says “Did

you ever bite a lemon?” In the second, called substitution, the letters of the plain text retain their

original relative positions but are replaced by

other letters with different sound values, or by

symbols of some sort, so that the original text

becomes unintelligible.

Nobody will quarrel with you very hard if you

wish to say that a code system is nothing but a

specialized form of substitution; but it’s best to

use the word “code” when a codebook is involved,

and to use “substitution cipher” when a literal

system of substitution is used.

It is possible to encrypt a message by a substitution method and then to apply a transposition

method to the substitution text, or vice versa.

Combined transposition-substitution ciphers do

not form a third class of ciphers; they are only

occasionally encountered in military cryptography. Applying a cipher to code groups is a very

frequently used procedure, and we’ll see cases of

that too.

Fig. 2
Page 9

Now for an example of a cryptogram in code.

In figure 3 is a plaintext message in the handwriting of President Wilson to his special emissary in

London, Colonel House. Contained in figure 4 is

the cryptogram after the plain text was encoded

by Mrs. Wilson. The president himself then typed

out the final message on his own typewriter, for

transmission by the Department of State. It

would appear that President Wilson lacked confidence in the security of the Department of State’s

methods – and maybe with good reason, as may

be seen in the following extract from a letter

dated 14 September 1914 from the president to

Ambassador Page in London: “We have for some

time been trying to trace the leaks, for they have

occurred frequently, and we are now convinced

that our code is in possession of persons at intermediary points. We are going to take thoroughgoing measures.” Perhaps one of the measures was

that the president got himself a code of his own. I

must follow this up some day.

A cipher device is a relatively simple mechanical contrivance for encipherment and decipherment, usually hand-operated or manipulated by

the fingers, for example, a device with concentric

rings of alphabets, manually powered. In figure 5

is an example – a cipher device with such rings.

I’ll tell you about it later. A cipher machine is a

relatively complex apparatus or mechanism for

encipherment and decipherment, usually

equipped with a typewriter keyboard and generally requiring an external power source. Modern

cryptology, following the trend in mechanization

and automation in other fields, now deals largely

with cipher machines, some highly complicated.

Figure 6 shows an example of a modern cipher

machine with keyboard and printing mechanism.

One of the expressions that uninformed laymen use, but that you must never use, is “the

German code,” or “the Japanese code,” or “the

Navy cipher,” and the like. When you hear this

sort of expression, you may put the speaker down

at once as a novice. There are literally hundreds of

different codes and ciphers in simultaneous use

by every large and important government or service, each suited to a special purpose; or where

there is a multiplicity of systems of the same general nature, the object is to prevent a great deal of

traffic being encrypted in the same key, thus overloading the system and making it vulnerable to

attack by methods and procedures to be mentioned in broad terms in a few moments.

The need for secrecy in the conduct of important affairs has been recognized from time immemorial. In the case of diplomacy and organized

warfare, this need is especially important in

regard to communications. However, when such

Fig. 3

Fig. 4

Fig. 5
Page 10

communications are transmitted by electrical

means, they can be heard or, as we say, intercepted, and copied by unauthorized persons, usually

referred to collectively as the enemy. The protection resulting from all measures designed to deny

to the enemy information of value that may be

derived from the interception and study of such

communications is called communications security or, for short, COMSEC.

In theory, any cryptosystem except one, to be

discussed in due time, can be attacked and “broken,” i.e., solved, if enough time, labor, and skill

are devoted to it, and if the volume of traffic in

that system is large enough. This can be done

even if the general system and the specific key are

unknown at the start. You will remember that I

prefaced my statement any cryptosystem can be

solved by saying “in theory,” because in military

operations theoretical rules usually give way to

practical considerations.

That branch of cryptology that deals with the

principles, methods, and means employed in the

solution or analysis of cryptosystems is called

cryptanalytics. The steps and operations performed in applying the principles of cryptanalytics constitute cryptanalysis. To cryptanalyze a

cryptogram is to solve it by cryptanalysis. A person skilled in the art of cryptanalysis is called a

cryptanalyst, and a clerk who assists in such

work is called a cryptanalytic clerk.

Information derived from the organized

interception, study, and analysis of the enemy’s

communications is called communications intelligence or, for short, COMINT. Let us take careful

note that COMINT and COMSEC deal with communications. Although no phenomenon is more

familiar to us than that of communication, the

fact of the matter is that this magic word means

many things to many people. A definition of communication that is broad enough for our purposes would be that communication deals with intelligent messages exchanged between intelligent

beings. This implies that human beings and

human operators are involved in the preparation,

encryption, transmission, reception, decryption,

and recording of messages that at some stage or

stages are in written form and in some stage or

stages are in electrical form as signals of one sort

or another. But in recent years there have come

into prominence and importance electrical signals that are not of the sort I’ve just indicated.

They do not carry “messages” in the usual sense

of the word; they do not convey from one human

being to another an intelligible sequence of words

and an intelligible sense. I refer here to electrical

or electronic signals such as are employed in

homing or directional beacons, in radar, in

telemetering or recording data of an electrical or

electronic nature at a distance, and so on.

Information obtained from a study of enemy electronic emissions of these sorts is called electronic

intelligence or, for short, ELINT. COMINT and

ELINT comprise SIGINT, that is, signals intelligence. Cryptology is the science that is concerned

with all these branches of secret signaling.

Fig.6. TSEC/KL-7 Cipher Machine (U.S.)
Page 11

In this series of lectures we shall be concerned

only with COMSEC and COMINT, leaving for

others and for other times the subject of ELINT.

This means that we shall deal with communications or messages.

Communication may be conducted by any

means susceptible of ultimate interpretation by

one of the five senses, but those most commonly

used are seeing and hearing. Aside from the use

of simple visual and auditory signals for communication over relatively short distances, the usual

method of communication between or among

individuals separated from another by relatively

long distances involves, at one stage or another,

the act of writing or of speaking over a telephone.

Privacy or secrecy in communication by telephone can be obtained by using equipment that

affects the electrical currents involved in telephony, so that the conversations can be understood

only by persons provided with suitable equipment properly arranged for the purpose. The

same thing is true in the case of facsimile transmission (i.e., the electrical transmission of ordinary writing, pictures, drawings, maps). Even

today there are already simple forms of enciphered television transmissions. Enciphered facsimile is called cifax; enciphered telephony,

ciphony; and enciphered television, civision.

However, these lectures will not deal with these

electrically and cryptanalytically more complex

forms of cryptology. We shall stick to enciphered

or encrypted writing – which will be hard enough

for most of us.

Writing may be either visible or invisible. In

the former, the characters are inscribed with ordinary writing materials and can be seen with the

naked eye; in the latter, the characters are

inscribed by means or methods that make the

writing invisible to the naked eye. Invisible writing can be prepared with certain chemicals called

sympathetic or secret inks, and in order to “develop” such writing, that is, make it visible, special

processes must usually be applied. Shown in figure 7 is an interesting example – the developed

secret-ink message that figured in an

$80,000,000 suit won by two American firms

against the German government after World War

I sabotage was proved, There are also methods of

producing writing that is invisible to the naked

eye because the characters are of microscopic

size, thus requiring special microscopic and photographic apparatus to enlarge such writing

enough to make it visible. Here’s an example – a

code message in a space not much larger than the

head of a pin (fig. 8). A simple definition of secret

writing would be to say that it comprises invisible

writing and unintelligible visible writing.

There is one additional piece of basic information that it is wise to call to your attention

before we proceed much further, and I’ll begin by

stating that the greatest and the most powerful

instrument or weapon ever forged and improved

by man in his long struggle for emancipation

from utter dependence upon his own environment is the weapon of literacy – a mastery of

reading and writing; and the most important

invention, the one that made the weapon of literacy practical, was the invention of the alphabet. It

is therefore a rather striking anomaly that we

should now come to the study of another weapon

– a counterweapon to the weapon of literacy – the

weapon of secrecy, the basic intent of which is to

thwart the weapon that man struggled so long to

forge. Secrecy is applied to make writing more

difficult and the reading of the writing very difficult, if not impossible.

Perhaps this is a good place to do a bit of theorizing about this matter of secrecy and what it

implies.

Every person who enciphers a piece of writing, a message, or a text of any kind, for the purpose of hiding something or keeping something

secret, does so with the idea that some other person, removed from him in distance, or time, or

both, is intended to decipher the writing or message and thus uncover the secret that was so hid
Page 12

The Yukon Trail THE BLUE

Fig. 7
Page 13

den. A person may possess a certain piece of

knowledge that he does not wish to forget, but

that he is nevertheless unwilling to commit to

open writing, and therefore he may jot it down in

cryptic form for himself to decipher later, when or

if the information is needed. The most widely

known example of such a cryptogram is found in

Edgar Allan Poe’s romantic tale “The Gold Bug.”

That sort of usage of cryptography, however, is

unusual. There are also examples of the use of

cipher writing to establish priority of discovery, as

did the astronomers Galileo and Huygens. I suppose I should at least mention another sort of

cryptic writing famous in literary history, the

diaries of persons such as Samuel Pepys and

William Byrd. These are commonly regarded as

being “in cipher,” but they were actually written

in a more or less private shorthand and can easily be read without the help of cryptanalysis. In figure 9 is shown a page of Pepys’ diary.

Now there can be no logical reason, point, or

purpose in taking the time and trouble to encipher anything unless it is expected that some

other person is to decipher the cipher some time

in the future. This means that there must exist

some very direct, clear-cut and unambiguous

relationship between the enciphering and deciphering operations. Just what such a relationship

involves will be dealt with later, but at this

moment all that it is necessary to say is that in

enciphering there must be rules that govern or

control the operations, that these rules must

admit of no uncertainty or ambiguity, and that

they must be susceptible of being applied with

undeviating precision, since otherwise it will be

difficult or perhaps impossible for the decipherer

to obtain the correct answer when he reverses the

processes or steps followed in the encipherment.

This may be a good place to point out that a

valid or authentic cryptanalytic solution cannot

be considered as being merely what the cryptanalyst thinks or says he thinks the cryptogram

means, nor does the solution represent an opinion of the cryptanalyst. Solutions are valid only

insofar as they are objective and susceptible of

demonstration or proof employing scientifically

acceptable methods or procedures. It should

hardly be necessary to indicate that the validity of

the results achieved by cryptanalytic studies of

authentic cryptograms rests upon the same sure

and well-established scientific foundations, and is

reached by the same sort of logic as are the discoveries, results, or “answers” achieved by any

other scientific studies, namely, observation,

hypothesis, deduction, induction, and confirmatory experiment. Implied in what I have just said

is the tacitly understood and now rarely explicitly

Fig. 8
Page 14

stated assumption that two or more equally competent and, if necessary, specially qualified investigators, each working independently upon the same

material, will achieve identical or practically identical results. 

Cryptology is usually and properly considered

to be a branch of mathematics, although Francis

Bacon considered it also a branch of grammar and

what we now call linguistics. Mathematical and statistical considerations play an ever-increasing and

prominent role in practical cryptology, but don’t let

my statement of this point frighten those of you

who have not had much formal instruction in these

subjects. We have excellent cryptologists who have

never studied more than arithmetic, and some of

our best ones would hide if you were to go searching for mathematicians around here. What is needed is the ability to reason logically, as the mathematician sometimes does, and this ability is found

Fig. 9
Page 15

in the most curious sorts of persons and places. So

those of you who are frightened by the words mathematics and statistics take heart – you’re not nearly so badly off as you may fear.

But now to return to the main theme, the place

mathematics occupies in cryptology, let me say that

just as the solution of mathematical problems

leaves no room for the exercise of divination or

other mysterious mental or psychic powers, so a

valid solution to a cryptogram must leave no room

for the exercise of such powers. In cryptologic science there is one and only one valid solution to a

cryptogram, just as there is but one correct solution

or “solution set” to any problem in mathematics.

But perhaps I’ve already dwelt on this point too

long; in any case, we’ll come back to it later, when

we come to look at certain types of what we may call

pseudociphers.

In the next lecture I’m going to give you a brief

glimpse into the background or history of cryptology, which makes a long and interesting story that

has never been told accurately and in detail. The

history of communications security, that is, of cryptography, and the history of communications intelligence, that is, of cryptanalysis, which are but

opposite faces of the same coin, deserve detailed

treatment, but I am dubious that this sort of history will ever be written because of the curtain of

secrecy and silence that officially surrounds the

whole field of cryptology. Authentic information on

the background and development of these vital

matters having to do with the security of a nation is

understandably quite sparse.

But in the succeeding lectures I’ll try my best to

give you authentic information, and where there’s

conjecture or doubt I’ll so indicate. I must add,

however, that in this series I’m going to have to

omit many highly interesting episodes and bits of

information, not only because these lectures are of

low classification, but also because we won’t and

can’t for security considerations go beyond a certain period in cryptologic history. Nevertheless, I

hope that you won’t be disappointed and that you’ll

learn certain things of great interest and importance, things to remember if you wish to make cryptology your vocation in life.

Page 17

As I said at the close of the preceding lecture, a

bit of history is always useful in introducing a subject belonging to a special and not too well-known

field; therefore, I’ll proceed with some historical

information about cryptology, which, as you

learned before, comprises two closely related sciences, namely, cryptography and cryptanalysis. I

will repeat and emphasize that they are but opposite faces of the same valuable coin; progress in one

inevitably leads to progress in the other, and to be

efficient in cryptology you must know something

about each of them.

Cryptography and cryptanalysis probably go

back to the dawn of the invention and development

of the art of writing itself. In fact, there is reason for

speculating as to which came first – the invention of

writing or the invention of cryptography; it’s somewhat like the question about which came first – the

hen or the egg. It is possible that some phases of

cryptography came before the art of writing had

advanced very far.

I’ve mentioned the art of writing. As in the case

of other seemingly simple questions – such as “why

is grass green?” – when we are asked to define writing, we can’t find a very simple answer, just because

the answer isn’t at all simple. Yet, Breasted, the

famous University of Chicago historian and

Orientalist, once said: “The invention of writing

and of a convenient system of records on paper has

had a greater influence in uplifting the human race

than any other intellectual achievement in the

career of man.” There has been, in my humble opinion, no greater invention in all history. The invention of writing formed the real beginning of civilization. As language distinguishes man from other

animals, so writing distinguishes civilized man

from the barbarian. To put the matter briefly, writing exists only in a civilization, and a civilization

cannot exist without writing. Let me remind you

that animals and insects do communicate – there’s

no question about that; but writing is a thing peculiar to man and found only as a phenomenon in

which man – and no animal or insect – engages.

Mankind lived and functioned for an enormous

number of centuries before writing was discovered,

and there is no doubt that writing was preceded by

articulate speech for eons – but civilization began

only when men got the idea of and invented the art

of writing. In Western or Occidental civilization,

writing is, in essence, a means of representing the

sounds of what we call speech or spoken language.

Other systems of writing were and some still are

handicapped by trying to represent things and

ideas by pictures. I’m being a bit solemn about this

great invention because I want to impress upon you

what our studies in cryptology are really intended

to do, namely, to defeat the basic or intended purpose of that great invention: instead of recording

things and ideas for the dissemination of knowledge, we want and strive our utmost to prevent this

aim from being realized, except among our own

brethren and under certain special circumstances,

for the purpose of our mutual security, our selfpreservation. And that’s important.

Writing is a comparatively new thing in the history of mankind. No complete system of writing

was used before about 3500 B.C.

Ordinary writing, the sort of writing you and I

use, is perhaps an outgrowth or development of picture writing or rebus writing, which I’m sure most

of you enjoyed as children. A rebus contains features of both ordinary and cryptographic writing;

you have to “decrypt” the significance of some of

the symbols, combine single letters with syllables,

pronounce the word that is represented by pictures,

and so on. Figure 10 is an example that I have

through the courtesy of the Bell Telephone

Lecture II
Page 18

Laboratories. See how much of it you can make out

in half a minute.

From rebus writing there came in due course

alphabetic writing, and let me say right now that

the invention of the alphabet – which apparently

happened only once in the history of mankind, in

some Middle East Semitic region, in or near the

Palestine-Syria area, then spread throughout the

whole of the European continent, and finally

throughout most of the world – is Western man’s

greatest, most important, and most far-reaching

invention because it forms the foundation of practically all our written and printed knowledge, except

that in Chinese. The great achievement of the

invention of the alphabet was certainly not the creation of the signs or symbols. It involved two brilliant ideas. The first was the idea of representing

merely the sounds of speech by symbols, that is, the

idea of what we may call phoneticization; the second was the idea of adopting a system in which,

roughly speaking, each speech sound is denoted or

represented by one and only one symbol. Simple as

these two ideas seem to us now, the invention was

apparently made, as I’ve said, only once, and the

inventor or inventors of the alphabet deserve to be

ranked among the greatest benefactors of mankind.

It made possible the recording of the memory of

mankind in our libraries, and from that single

invention have come all past and present alphabets.

Some of the greatest of men’s achievements we are

now apt to take for granted; we seldom give them

Fig. 10
Page 19

any thought. The invention of the art of writing and

the invention of the alphabet are two such achievements, and they are worth pondering upon. Where

would we be without them? Note that among living

languages Chinese presents special problems not

only for the cryptologist but also for the Chinese

themselves. No Sinologist knows all the 80,000 or

so Chinese symbols, and it is also far from easy to

master merely the 9,000 or so symbols actually

employed by Chinese scholars. How far more simple it is to use only twenty to twenty-six symbols!

Since Chinese is a monosyllabic language, it seems

almost hopeless to try to write Chinese by the sort

of mechanism used in an alphabetic polysyllabic

language; attempts along these lines have been

unsuccessful, and the difficulties in memorizing a

great many Chinese characters, account for the fact

that even now only about ten percent of the Chinese

people can read or write to any significant degree.

The spread of knowledge in Chinese is thereby

much hampered.

We find instances of ciphers in the Bible. In

Jeremiah 25:26, occurs this expression: “And the

King of Sheshakh shall drink after them.” Also,

again in Jeremiah 51:41: “How is Sheshakh taken!”

Well, for perhaps many years that name

“Sheshakh” remained a mystery, because no such

place was known to geographers or historians. But

then it was discovered that if you write the twentytwo letters of the Hebrew alphabet in two rows, –

eleven in one row and eleven in the other, as in figure 11, you set up a substitution alphabet whereby

you can replace letters by those standing opposite

them. For example, “shin” is represented by “beth”

or vice versa, so that “Sheshakh” translates “Babel,”

which is the old name of “Babylon.” Hebrew then

did not have and still doesn’t have vowels; they

must be supplied. This is an example of what is

called ATHBASH writing, that is, where aleph, the

first letter is replaced by teth, the last letter; beth,

the second letter, by shin, the next-to-the-last, etc.

By sliding the second row of letters one letter each

time there are eleven different cipher alphabets

available for use. The old Talmudists went in for

cryptography to a considerable extent. Incidentally,

in mentioning the Bible, I will add that Daniel, who,

after Joseph in Genesis, was an early interpreter of

dreams and therefore one of the first psychoanalysts, was also the first cryptanalyst. I say that he

Fig. 11
Page 20

was an early psychoanalyst because you will

remember that he interpreted Nebuchadnezzar’s

dreams. In the Bible’s own words,

“Nebuchadnezzar dreamed dreams, wherewith his

spirit was troubled, and sleep brake from him.” But,

unfortunately, when he woke up he just couldn’t

remember those troublesome dreams. One morning he called for his wise men, magicians,

astrologers, and Chaldean sorcerers and asked

them to interpret the dream he’d had during the

preceding night. “Well, now, tell us the dream and

we’ll try to interpret it,” they said. To which King

Nebuchadnezzar exclaimed, “The thing is gone

from me. I don’t remember it. But it’s part of your

job to find that out, too, and interpret it. And if you

can’t tell me what the dream was, and interpret it,

things will happen to you.” What the king asked

was a pretty stiff assignment, of course, and it’s no

wonder they failed to make good, which irked

Nebuchadnezzar no end. Kings had a nasty habit of

chopping your head off in those days if you failed or

made a mistake, just as certain arbitrary and cruel

despots are apt to do even in modern times for

more minor infractions, such as not following the

Party Line. So in this case it comes as no surprise to

learn that Nebuchadnezzar passed the word along

to destroy all the wise men of Babylon, among

whom was one of the wise men of Israel, named

Daniel. Well, when the king’s guard came to fetch

him, Daniel begged that he be given just a bit more

time. Then, by some act of divination – the Bible

simply says that the secret was revealed to Daniel in

a night vision – Daniel was able to reconstruct the

dream and then to interpret it. Daniel’s reputation

was made.

Some years later, Nebuchadnezzar’s son

Belshazzar was giving a feast, and, during the

course of the feast, in the words of the Bible, “came

forth fingers of a man’s hand and wrote over

against the candlestick upon the poster of the wall.”

The hand wrote a secret message. You can imagine

the spinechilling scene. Belshazzar was very much

upset, and just as his father did, he called for his

wise men, soothsayers, Chaldean sorcerers, magicians and so on, but they couldn’t read the message.

Apparently they couldn’t even read the cipher characters! Well, Belshazzar’s queen fortunately

remembered what that Israelite Daniel had done

years before, and she suggested that Daniel be

called in as a consultant. Daniel was called in by

Belshazzar, and he succeeded in doing two things.

He succeeded not only in reading the writing on the

wall: “MENE, MENE, TEKEL, UPHARSIN,” but

also in deciphering the meaning of those strange

words. His interpretation: “Mene”– “God hath

numbered thy kingdom and finished it.” “Tekel” –

“Thou are weighed in the balances and found wanting.” “Upharsin” – “Thy kingdom shall be divided

and given to the Medes and Persians.” Apparently

the chap who did the handwriting on the wall knew

a thing or two about cryptography, because he used

what we call “variants,” or different values, for in

one case the last word in the secret writing on the

wall is “Upharsin” and in the other it is “Peres”; the

commentators are a bit vague as to why there are

these two versions of the word in the Bible. At any

rate, Babylon was finished, just as the inscription

prophesied; it died with Belshazzar. I think this

curious Biblical case of the use of cryptography is

interesting because I don’t think anybody has really found the true meaning of the sentence in secret

writing, or explained why the writing on the wall

was unintelligible to all of Belshazzar’s wise men.

Probably the earliest reliable information on the

use of cryptography in connection with an alphabetic language dates from about 900 B.C. Plutarch

mentioned that from the time of Lycurgus there

was in use among the Lacedemonians, or ancient

Spartans, a device called the scytale. This device,

which I’ll explain in a moment, was definitely

known to have been used in the time of Lysander,

which would place it about 400 B.C. This is about

the time that Aeneas Taciticus wrote his large treatise on the defense of fortification, in which there is

a chapter devoted specifically to cryptography. In

addition to mentioning ways of physically concealing messages, a peculiar sort of cipher disk is

described. Also a method of replacing words and

letters by dots is mentioned.
Page 21

Figure 12 is a picture of the scytale, one of

the earliest cipher devices history records.

The scytale was a wooden cylinder of specific dimensions around which they wrapped

spirally a piece of parchment or leather; they

then wrote the message on the parchment,

unwound it, and sent it to its destination by a safe

courier, who handed it over to the commander for

whom it was intended and who, having been provided with an identically dimensioned cylinder,

would wind the strip of leather or parchment

around his cylinder and thus bring together properly the letters representing the message. This diagram may not be accurate. I don’t think anyone

really understands the scheme. The writing was

done across the edges of the parchment, according

to some accounts, and not between the edges, as

shown here. Incidentally, you may be interested to

learn that the baton the European field marshal still

carries as one of the insignia of his high office

derives from this very instrument.

We don’t know much about the use of cryptography by the Romans, but it is well known that

Caesar used an obviously simple method; all he did

was to replace each letter by the one that was fourth

from it in the alphabet. For example, A would be

represented by D, B by E, and so on. Augustus

Caesar is said to have used the same sort of thing,

only it was even more simple: each letter was

replaced by the one that followed it in the alphabet.

Cicero was one of the inventors of what is now

called shorthand. He had a slave by the name of

Tiro, who wrote Cicero’s records in what are called

Tironian notes. Modern shorthand is a development of Tiro’s notation system.

In figure 13 we see some cipher alphabets of

olden times, alphabets used by certain historical

figures you’ll all remember. The first cipher alphabet in this figure was employed by Charlemagne,

who reigned from 768 to 814 A.D. The second one

was used in England during the reign of Alfred the

Great, 871 to 899. The third alphabet is called

Ogam Writing and was used in ancient Ireland. The

alphabets below that were used much later in

England: the fourth one was used by Charles the

First in 1646; the fifth, the so-called “clock cipher,”

was used by the Marquis of Worcester in the seventeenth century; finally, the last one was used by

Cardinal Wolsey in about 1524.

In the Middle Ages cryptography appears first

as a method of concealing proper names, usually by

the simple substitution of each letter by the next

one in the alphabet, just about as Augustus Caesar

did hundreds of years before. At other times the

vowels were replaced by dots, without changing the

consonants – a method that was used throughout

Europe to about 1000 A.D., when letters began to

be replaced by various signs, by other letters, by letters from another language, by runes which are

found in abundance in Scandinavia, and by arbitrary symbols. Figure 14 is an example of a runic

inscription on a stone that stands before Gripsholm

Castle near Stockholm, Sweden. The word rune

means “secret.”

Within a couple of hundred years, the outlines

of modern cryptography began to be formed by the

secret correspondence systems employed by the

Fig. 12.

Fig. 13
Page 22

small papal states in Italy. In fact, the real beginnings of systematic, modern cryptology can be

traced back to the days of the early years of the thirteenth century, when the science began to be extensively employed by the princes and chanceries of

the papal states in their diplomatic relations

amongst themselves and with other countries in

Europe. The necessity for secret communication

was first met by attempts inspired by or derived

from ancient cryptography, as I’ve outlined so far.

There was a special predilection for vowel substitution, but there appeared about this time one of the

elements that was later to play a very prominent

role in all cipher systems, an element we now call a

syllabary or a repertory. These were lists of letters,

syllables, frequently used parts of speech and

words, with additions of arbitrary equivalents for

the names of persons and places. There is still in

existence one such syllabary and list of arbitrary

equivalents that was used about 1236 A.D., and

there are other examples that were used in Venice

in 1350.

Among examples of ciphers in medieval cryptography is a collection of letters of the Archbishop

of Naples, written between 1363 and 1365, in which

he begins merely with symbol substitutions for the

vowels and uses the letters that are actually vowels

to serve as nulls or nonsignificant letters to throw

the would-be cryptanalyst off the right track. As a

final development, the high-frequency consonants

L, M, N, R, and S, and all the vowels, are replaced

not only by arbitrary symbols but also by other letters.

About 1378 an experienced cryptologist named

Gabriele Lavinde of Parma was employed as a professional by Clement VII, and in the Vatican Library

is a collection of ciphers devised and used by

Lavinde about 1379. It consists of repertories in

which every letter is replaced by an arbitrary symbol. Some of these ciphers also have nulls and arbitrary equivalents or signs for the names of persons

and places. There is a court cipher of Mantua, dated

1395, that used this system.

Fig. 14. A couple of old ruins
Page 23

At the beginning of the fifteenth century, the

necessity of having variants for the high-frequency

letters, especially the vowels, became obvious.

Figure 15 is an alphabet of that period that is interesting because it shows that even in those early days

of cryptology there was already a recognition of the

basic weakness of what we call single or monoalphabetic substitution, that is, where every letter in

the plaintext message is represented by another

and always the same letter.

Solution of this type of cipher, as many of you

may know, is accomplished by taking advantage of

the fact that the letters of an alphabetic language

are used with greatly differing frequencies. I don’t

have to go into that now because many of you, at

some time or other, have read Edgar Allan Poe’s

“The Gold Bug” and understand the principles of

that sort of analysis. It is clearly shown in the figure

that the early Italian cryptographers understood

the fact of varying frequencies and introduced

stumbling blocks to quick and easy solution by having the high-frequency letters represented by more

than a single character, or by several characters, as

you can see. I will add that the earliest tract that the

world possesses on the subject of cryptography, or

for that matter, cryptanalysis, is that which was

written in 1474 by a Neapolitan, Sicco Simonetta.

He set forth the basic principles and methods of

solving ciphers, simple ciphers no doubt, but he

describes them and their solution in a very clear

and concise form.

Cipher systems of the type I’ve described continued to be improved, In figure 16 is shown what

we may call the first complete cipher system of this

sort. There are substitution symbols for each letter;

the vowels have several equivalents; there are nulls;

and there is a small list of arbitrary symbols, such as

those for “the pope,” the word “and,” the preposition “with,” and so on, This cipher, dated 1411, was

used in Venice, and it is typical of the ciphers used

by the papal chanceries of those days. 

The step remaining to be taken in the development of these ciphers was to expand the “vocabulary,” that is, the list of equivalents for frequently

used words and syllables, the names of persons and

places, parts of speech, and so on. This step was

reached in Italy during the first half of the fifteenth

century and became the prototype of diplomatic

ciphers used in practically all the states of Europe

for several centuries. One of seventy ciphers collected in a Vatican codex and used from about 1440

to 1469 is shown in figure 17. Note that the equivalents of the plaintext items are Latin words and

combinations of two and three letters and that they

are listed in an order that is somewhat alphabetical

but not strictly so. I suppose that by constant use

the cipher clerks would learn the equivalents

Fig. 15
Page 24

almost by heart, so that an adherence to a strict

alphabetic sequence either for the plaintext items

or for their cipher equivalents didn’t hamper their

operations too much, In figure 18 there is much the

same sort of arrangement, except that now the

cipher equivalents seem to be digraphs, and these

are arranged in a rather systematic order for ease in

enciphering and deciphering. Now we have the real

beginnings of what we call a one-part code, that is,

the same list will serve both for encoding and

decoding. These systems, as I’ve said, remained the

prototypes of the cryptography employed throughout the whole of Europe for some centuries. The

papal states used them, and as late as 1793 we find

them used in France. I wish here to mention specifically the so-called King’s General Cipher used in

1562 by the Spanish Court. It is shown in figure 19.

But there were two exceptional cases that show

that the rigidity of cryptographic thought was now

and then broken during the four centuries we have

been talking about in this brief historical survey,

Some of the papal ciphers of the sixteenth century

and those of the French Court under Kings Louis

XIII and XIV exemplify these exceptions. In the

case of these French Court ciphers, we find that a

French cryptologist named Antonio Rossignol, who

was employed by Cardinal Richelieu, understood

quite well the weaknesses of the one-part code and

syllabaries. It was he who, in about 1640, introduced a new and important improvement: the idea

of the two-part code or syllabary, in which for

encoding a message the items in the vocabulary are

listed in some systematic order, nearly always

alphabetical; the code equivalents, whatever they

may be, are assigned to the alphabetically listed

items in random order. This means that there must

be another arrangement or book for ease in decoding, in which the code equivalents are listed in systematic order, numerically or alphabetically as the

case may be, and alongside each appears its meaning in the encoding arrangement, or book. The sigFig. 16
Page 25

nificance of this improvement you’ll find out sooner or later, Codes of this sort also had variants –

Rossignol was clever, indeed. One such code, found

in the 1691 correspondence of Louis XIV, had about

600 items, with code groups of two and three digits. Not at all bad, for those days!

Now this sort of system would appear to be

quite secure, and I suppose it was indeed so for

those early days of cryptographic development –

but it wasn’t proof against the cleverness of British

brains, for the eminent mathematician John Wallis

solved messages in it in 1689. Never underestimate

the British in this science – as we’ll have reason to

note in another lecture in this series.1

French cryptography under Kings Louis XV and

XVI declined, reaching perhaps its lowest level

under Napoleon the Great. It is a fact that in

Napoleon’s Russian enterprise the whole of his

army used but a single codebook of only 200

groups, practically without variants, even for the

high-frequency letters. Furthermore, not all the

words in a message were encoded – only those that

the code clerk or the writer thought were important. It’s pretty clear that the Russians intercepted

and read many of Napoleon’s messages – this

comes from categorical statements to this effect by

Czar Alexander I himself. We won’t be far wrong in

believing that the weaknesses of Napoleon’s cryptocommunications formed an important factor in

Napoleon’s disaster. One hundred twenty-five

years later, Russian ineptitude in cryptographic

communications lost them the Battle of

Tannenberg and eventually knocked them out of

World War I.

Fig. 17

Fig. 18
Page 26

The other sixteenth century papal ciphers that

constituted the second exception to the general

similarity of cryptographic systems of those days

were quite different from those I’ve shown you. In

this exception the ciphers were monoalphabetic,

but some letters had the same equivalent, so that on

decipherment the context had to be used to decide

which of two or more possible plaintext values was

the one meant by each cipher letter. One such

cipher, used by the Maltese Inquisitor in 1585, is

shown below: You’ll note that the digit 0 has two

values, A and T; the digit 2 has three values, U, V,

and B, and so on. There were two digits used as

nulls, 1 and 8; digits with dots above them stood for

words such as qua, que, qui, and so on,

Page 27 shows a message and its encipherment:

A bit tricky, isn’t it? Many, many years later Edgar

Allan Poe described a cipher of this same general

type, where the decipherer must choose between

two or more possible plaintext equivalents in buildFig. 19

CIPHER OF THE INQUISITOR OF MALTA (1585)

(From SACCO, MANUALE DE CRITTOGRAFIA, 1947)

Plain: A,T E,F I,G O,D U,V,B C,L,N M,R P,S,Z

Cipher: 0 3 5 4 2 6 9 7

Nulls: 1,8

Plain: qua que qui quo che chi non quando perché et per

. . . . . . . . . .

Cipher: 7 9 6 2 4 5 3 0 1,8
Page 27

ing up his plain text, the latter guiding the choice of

the right equivalent. The trouble with this sort of

cipher is that you have to have pretty smart cipher

clerks to operate it, and even then I imagine that in

many places there would be doubtful decipherments of words. It wasn’t really a practical system

even in those days, but it could, if used skillfully and

with only a small amount of text, give a cryptanalyst

plenty of headaches. But such systems didn’t last

very long because of the practical difficulties in

using them.

The first regular or official cipher bureau in the

Vatican was established in about 1540 and in

Venice at about the same time, about 100 years

before a regular cipher bureau was established in

France by Cardinal Richelieu. It is interesting to

observe that no new or remarkable ideas for cryptosystems were developed for a couple of hundred

years after the complex ones I’ve described as having been developed by the various papal cryptologists. One-part and two-part syllabaries and simple

or complex ones with variants were in use for many

decades, but later on, in a few cases, the code equivalents were superenciphered, that is, the code

groups formed the text for the application of a

cipher, generally by rather simple systems of additives. Governmental codes were of the two-part

type and were superenciphered by the more sophisticated countries.

The first book or extensive treatise on cryptography is that by a German abbot named Trithemius,

who published in 1531 the first volume of a planned

monumental four-volume work. I said that he

planned to publish four volumes; but he gave up

after the third one, because he wrote so obscurely

and made such fantastic claims that he was charged

with being in league with the Devil, which was a

rather dangerous association in those or even in

these days. They didn’t burn Trithemius, but they

did burn his books. Figure 20 illustrates that the

necessity for secrecy in this business was recognized from the very earliest days of cryptology, and

certainly by Trithemius. Here is the sort of oath that

Trithemius recommended be administered to students in the science of cryptology. All of you have

subscribed to a somewhat similar oath, but we can

now go further and back up the oath with a rather

strict law. You’ve all read it, I’m sure.

We come now to some examples from more

recent history. In figure 21 we see a cipher 

alphabet used by Mary, Queen of Scots, who

reigned from 1542 to 1567 and was beheaded in

1587. In this connection it may interest you to learn

that question has been raised as to whether the

Cipher: 4 5 1 0 2 0 4 1 4 0 9 4 8 9 5 6 2 0 4 1 0 2 5 7 4

“Plain”: O I A U A O O A M O M I C U A O A U I P O

D G T B T D D T R D R G L B T D T B G S D

V N V V Z

Plain D I T U T O D A R O M I N U T O A V I S O

Cipher: 1 4 5 6 5 1 6 4 9 5 3 9 3 8

“Plain”: ET O I C I C O M I E M E

PER D G L G N D R G F R F

PERCHE N L

Plain: PER O G N I C O R I E R E
Page 28

Queen was “framed” by means of this forged postscript (fig. 22) in a cipher that was known to have

been used by her.

The Spanish Court under Philip II, in the years

1555-1598, used a great many ciphers, one of which

is shown in figure 23. You see that it is quite complex for those early days, and yet ciphers of this sort

were solved by an eminent French mathematician

named Vieta, the father of modern algebra. In 1589

he became a Councilor [sic] of Parliament at Tours

and then Privy Councillor. While in that job he

solved a Spanish cipher system using more than

500 characters, so that all the Spanish dispatches

falling into French hands were easily read. Philip

was so convinced of the security of his ciphers that

when he found the French were aware of the 

contents of his cipher dispatches to the

Netherlands, he complained to the pope that the

French were using sorcery against him. Vieta was

called on the carpet and forced to explain how he’d

solved the ciphers in order to avoid being convicted

of sorcery, a serious offense.

The next cryptologist I want you to know something about is another Italian savant who wrote a

book, published in 1563, in which he showed certain types of cipher alphabets that have come 

down in history and are famous as Porta’s alphabets. Figure 24 is an example of the Porta Table,

showing one alphabet with key letters A or B,

another alphabet with key letters C or D, and so on.

Fig. 20
Page 29

I don’t want to go into exactly how the key letters

are used; it is sufficient to say that even to this day

cryptograms using the Porta alphabets are occasionally encountered.

That Porta’s table was actually used in official

correspondence is shown by figure 25, which is a

picture of a table found among the state papers of

Queen Elizabeth’s time; it was used for communicating with the English ambassador to Spain. Porta

was, in my opinion, the greatest of the old writers

on cryptology. I also think he was one of the early,

but by no means the first, cryptanalyst able to solve

a system of keyed substitution, that is, where the

key is changing constantly as the message undergoes encipherment. Incidentally, Porta was also the

inventor of the photographic camera, the progenitor of which was known as the camera obscura.

Figure 26 is a picture of what cryptographers

usually call the Vigenère Square, the Vigenère

Table, or the Vigenère Tableau. It consists of a set of

twenty-six alphabets successively displaced one letter per row, with the plaintext letters at the top of

the square, the key letters at the side, and the cipher

letters inside. The method of using the table is to

agree upon a key word, which causes the equivalents of the plaintext letters to change as the key

changes. Vigenère is commonly credited with having invented that square and cipher, but he really

didn’t and, what’s more, never said he did. His

table, as it appears in his book, the first edition of

which was published in 1586, is shown in figure 27.

It is more complicated than as described in ordinary books on cryptology.

Figure 28 is one more example of another old

official cipher. In it we can see the alphabets that

could be slid up and down, as a means of changing

the key. Another early official cipher is shown in figure 29. It is a facsimile of a state cipher used in

Charles the First’s time, in 1627, for communicating

with France and Flanders. It involves coordinates,

and I want you to notice that there are two complete

alphabets inside it, intended to smooth out frequencies. The letters of the key words OPTIMUS

and DOMINUS serve as the coordinates used to

represent the letters inside the square. A third old

cipher, one used by George III in 1799, is shown in

figure 30.

One writer deserving special attention as a

knowledgeable cryptologist in the seventeenth century, and the one with whose cipher I’ll close this

lecture, is Sir Francis Bacon, who invented a very

useful cipher and mentioned it for the first time in

his Advancement of Learning, published in 1604 in

London. The description is so brief that I doubt

whether many persons understood what he was

driving at. But Bacon described it in full detail, with

examples, in his great book De Augmentis

Scientiarum, which was published almost twenty

years later, in 1623, and which first appeared in an

English translation by Gilbert Wats in 1640 under

the title The Advancement of Learning. Bacon

Fig. 22

Fig. 21
called his invention the Biliteral Cipher, and it is so

ingenious that I think you should be told about it so

that you will all fully understand it.

In his De Augmentis Bacon writes briefly about

ciphers in general and says that the virtues required

in them are three: “that they be easy and not laboPage 30

Fig. 23

Fig. 24

Fig. 25

Fig. 26
rious to write; that they be safe, and impossible to

be deciphered without the key; and lastly, that they

be, if possible, such as not to raise suspicion or to

elude inquiry.” He then goes on to say: “But for

avoiding suspicion altogether, I will add another

contrivance, which I devised myself when I was at

Paris in my early youth, and which I still think worthy of preservation.” Mind you, this was forty years

later! Let’s consult Bacon for further details. In figure 31 we see a couple of pages of the Gilbert Wats’

translation of Bacon’s De Augmentis Scientiarum.

Bacon shows what he calls “An Example of a Bi-literaire Alphabet,” that is, one composed of two elements that, taken in groupings of fives, yield thirtytwo permutations. You can use these permutations

to represent the letters of the alphabet, says Bacon,

but you need only twenty-four of them [because I

and J, U and V, were then used interchangeably].

These permutations of two different things – they

may be a’s and b’s, l’s and 2’s, pluses and minuses,

apples and oranges, anything you please – can be

used to express or signify messages. Bacon was, in

fact, the inventor of the binary code that forms the

basis of modern electronic digital computers.

Bacon gives a brief example in the word fuge – the

Latin equivalent of our modern scram – as can be

seen in figure 31. Figure 32 is another example,

which quite obviously isn’t what it appears to be – a

crude picture of a castle, in which there are shaded

and unshaded stones. It was drawn by a friend who

was a physician, and the message conveyed by it is

My business is to write prescriptions

And then to see my doses taken;

But now I find I spend my time

Endeavoring to out-Bacon Bacon.

Fig. 27

Page 31
Page 32

So far this is simple enough – too much so,

Bacon says, for the example he used in the case of

the word fuge is patently cryptic and would not

avoid suspicion under examination. So Bacon goes

on to describe the next step, which is to have at

hand a “Bi-formed Alphabet,” that is, one in which

all the letters of the alphabet, both capital and

small, are represented by two slightly different

forms of letters (fig. 33). Having these two different

forms at hand, when you want to encipher your

secret message, you write another external and

innocuous message five times as long as your secret

message, using the appropriate two forms of letters

to correspond to the a’s and b’s representing your

secret message. Here’s fuge (fig. 34), enciphered

within an external message saying “Manere te volo

donec veniam,” meaning “Stay where you are until

I come.” In other words, whereas the real message

says scram, the phony one says “Stick around

awhile; wait for me.” Bacon gives a much longer

example, the SPARTAN DISPATCH; here it is, and

here’s the secret message that it contains (fig. 35).

Bacon’s biliteral cipher is an extremely ingenious contrivance. There can be no question whatsoever about its authenticity and utility as a valid

cipher. Thousands of people have checked his long

example, and they all find the same answer – the

one that Bacon gives.

Figure 36 is a modern example that uses two

slightly different fonts of type called Garamond and

Fig. 28

Fig. 29

Fig. 30
Page 33

Imprint, which are so nearly alike that it takes good

eyes to differentiate them.

The fact that Bacon invented this cipher and

described it in such detail lends plausibility to a theory entertained by many persons that Bacon wrote

the Shakespeare plays and that he inserted secret

messages in those plays by using his cipher. If you’d

like to learn more about this theory, I suggest with

some diffidence that you read a book entitled The

Shakespearean Ciphers Examined. I use the word

diffidence because my wife and I wrote the book,

which was published in late 1957 by the Cambridge

University Press.

In the next lecture we’ll take up cryptology as

used during the period of the American Revolution

by both the colonial and the British forces in

America.

Fig. 31

Fig. 32
Page 34

Fig. 34

Fig. 36

Fig. 35

Fig. 33
Page 35

Continuing with our survey of cryptologic history, the period of the American Revolution in 

U.S. history is naturally of considerable interest 

to us and warrants more than cursory treatment.

Information regarding the codes and ciphers

employed during that period has been rather 

sparse until quite recently, when a book entitled

Turncoats, Traitors and Heroes by Colonel John

Bakeless, AUS, was published in 1959 by

Lippincott. After a good many years of research,

Colonel Bakeless brought together for the first 

time a considerable amount of authentic information on the subject, and some of it is incorporated in

this lecture.

According to Colonel Bakeless – and believe it

or not – in early 1775 the British commander in

chief in America, General Gage, had no code or

cipher at all, nor even a staff officer who knew how

to compile or devise one; he had to appeal to the

commanding general in Canada, from whom he

probably obtained the single substitution cipher

that was used in 1776 by a British secret agent who

– again, believe it or not – was General

Washington’s own director general of hospitals, Dr.

Benjamin Church. General Washington had means

for secret communication from the very beginning

of hostilities, probably even before the fighting

began at Lexington and Concord. If the British

under General Gage were poorly provided in this

respect, by the time Sir Henry Clinton took over

from General Howe, who succeeded Gage, they

were much better off – they had adequate or apparently adequate means for secret communication.

Are you astonished to learn that the systems

used by the American colonial forces and by the

British regulars were almost identical? You shouldn’t be, because the language and backgrounds of

both were identical. In one case, in fact, they used

the same dictionary as a code book, something that

was almost inevitable because there were so few

English dictionaries available. Here’s a list of the

systems they used:

a. Simple, monoalphabetic substitution – easy

to use and to change

b. Monoalphabetic substitution with variants,

by the use of a long key sentence. I’ll show you

presently an interesting example in Benjamin

Franklin’s system of correspondence with the elder

Dumas.

c. The Vigenère cipher with repeating key.

d. Transposition ciphers of simple sorts.

e. Dictionaries employed as code books, with

and without added encipherment. Two were specially favored, Entick’s New Spelling Dictionary

and Bailey’s English Dictionary. A couple of pages

from the former are shown in figure 37. To represent a word by code equivalent, you simply indicated the page number, then whether column 1 or column 2 contained the word you wanted, and then

the number of the word in the column. Thus, the

word jacket would be represented by 178-2-2.

f. Small, specially compiled, alphabetic one-part

codes of 600-700 items and code names – our old

friend the syllabary, or repertory, of hoary old age,

but in new dress. In some cases these were of the

“one-part” or “alphabetic” type.

g. Ordinary books, such as Blackstone’s

Commentaries on the Laws of England, giving the

page number, the line number, and the letter number in the line, to build up, letter-by-letter, the word

to be represented. Thus, 125-12-16 would indicate

Lecture III
Page 36

the 16th letter in the 12th line on page 125; it might

be the letter T.

h. Secret inks. Both the British and Americans

made extensive use of this method.

i. Special designs or geometric figures, such as

the one I’ll show you presently.

j. Various concealment methods, such as using

hollow quills of large feathers or hollowing out a

bullet and inserting messages written on very thin

paper. Strictly speaking, however, this sort of stratagem doesn’t belong to the field of cryptology. But

it’s a good dodge, to be used in special cases.

In the way of ciphers a bit more complex than

simple monoalphabetic substitution ciphers, the

British under Clinton’s command used a system

described by Bakeless in the following terms:

. . . a substitution cipher in which the

alphabet was reversed, “z” becoming “a”

and “a” becoming “z.” To destroy frequency clues, the cipher changed in each line of

the message, using “y” for “a” in the second line, “x” for “a” in the third, and so on.

When the cipher clerk reached “0” in the

middle of the alphabet, he started over

again. A spy using this cipher did not have

to carry incriminating papers, since the

system was easy to remember.

The alphabets of this scheme are simple

reversed standard alphabets:

Fig. 37
Page 37

Bakeless doesn’t explain why the cipher

sequences are only twelve in number – nor does the

source from which he obtained the information, a

note found among the Clinton Papers in the

Clements Library at the University of Michigan.

Bakeless continues:

Clinton also used another substitution

cipher, with different alphabets for the

first, second and third paragraphs. Even if

an American cryptanalyst should break

the cipher in one paragraph, he would

have to start all over in the next. As late as

1781, however, Sir Henry was using one

extremely clumsy substitution cipher, in

which “a” was 51, “d” was 54, “e,” 55.

Finding that “a” was 51 and “d” was 54,

anyone could guess (correctly) that “b”

was 52, “c” 53. Somewhat more complex

was his “pigpen” cipher, in which twentyfive letters of the alphabet were placed in

squares. Then an angle alone would represent a letter, the same angle with a dot

another letter, the same angle with two

dots still another. In some cases, cryptography was used only for a few crucial

words in an otherwise “clear” message, a

method also favored by certain American

officials.

Of the first cipher mentioned in the preceding

extract, there is much more to be said. Perhaps

Bakeless was limited by space considerations. In

any case, I will leave that story for another time and

place. As for the second cipher Bakeless mentions

in the extract, I can give you the whole alphabet, for

it exists among the Clinton Papers.

There is no explanation why the sequence

beginning with 50 stops with E-55 and then starting with F -60 goes straight on without any break to

Z- 78. (Remember that in those days I and J were

used interchangeably, as were U and V.) 
Page 38

Finally, as to what Bakeless (and others) calls

the “pigpen” cipher, this is nothing but the hoary

old so-called “Masonic” cipher based upon the fourcross figure that can accommodate twenty-seven

characters, not twenty-five, as Bakeless indicates.

Letters can be inserted in the design in many different arrangements.

I’ve mentioned that code or conventional

names were used to represent the names of important persons and places in these American colonial

and British cryptograms of the Revolution. Here

are examples selected from a list of code names prepared by the famous British spy, Major Andre, chief

of intelligence under General Clinton:

For American Generals — the names of the

Apostles, for instance:

General Washington was James

General Sullivan was Matthew

Names of Forts:

Fort Wyoming – Sodom

Fort Pitt – Gomorrha

Names of Cities:

Philadelphia – Jerusalem

Detroit – Alexandria

Names of Rivers and Bays:

Susquehanna – Jordan

Delaware – Red Sea

Miscellaneous:

Indians – Pharisees

Congress – Synagogue

I’m sure you’ve learned as school children all

about the treasonable conduct of Benedict Arnold

when he was in command of the American forces at

West Point; but you probably don’t know that practically all his exchanges of communications with Sir

Henry Clinton, commander of the British forces in

America, were in cipher or in invisible inks. One of

Arnold’s cipher messages, in which he offers to give

up West Point for £20,000, is shown below, figure

38a being the secret version, figure 38b, the plain

text. Arnold left a few words en clair, the ones he

considered unimportant; for the important ones he

used a dictionary as a codebook, indicating the page

number, column number and line number corresponding to the position in the dictionary of the

Fig. 38a

Fig. 38b
Page 39

plaintext word the code group represents. Arnold

added 7 to these numbers, which accounts for the

fact that the first number in a code group is never

less than 8, the central number is always either 8 or

9, and the third number is never less than 8 or more

than 36. The significant sentence appears near the

middle of the message: “If I 198-9-34, 185-8-31 a

197-8-8. . .” yields the plain text: lf I point out a plan

of cooperation by which S.H. (Sir Henry Clinton)

shall possess himself of West Point, the Garrison,

etc., etc., etc., twenty thousands pound Sterling I

think will be a cheap purchase for an object of so

much importance.” The signature 172-9-19 probably stands for the word “Moor”; Arnold’s code name

in these communications was “John Moore.” He

had also another name, “Gustavus.”

Figure

39 is a

message in

which he

gave the

British

information that

might have

led to the

capture of

his commander in

chief, General Washington; the top shows the code

message, the bottom the plain text. Arnold used the

same additive as in the preceding example.

Washington, however, was too smart to be

ambushed – he went by a route other than the one

he said he’d take.

You may find figure 40 interesting as an example of the special sort of mask or grille used by Fig.

39 Arnold and by the British in their negotiations

with him. The real or significant text is written in

lines outlined by an hourglass figure, and then

dummy words are supplied to fill up the lines so

that the entire letter apparently makes good sense.

To read the secret message, you’re supposed to

have the same size hourglass figure that was used to

conceal the secret message. In figure 40 the lefthand portion shows the “phony” message. Masks

having small rectangular apertures were also used,

the significant words being written so that they

were disclosed when the mask was placed on the

written message so as to isolate them from the nonsignificant words. The significant text in this example is shown in printed form to the right of the original hourglass design.

An interesting episode involving concealment

of this sort is recorded by Bakeless. An urgent message from Sir Henry Clinton, dated 8 October 1777,

and written on thin silk, was concealed in an oval

silver ball, about the size of a rifle bullet, which was

handed to Daniel Taylor, a young officer who had

been promised promotion if he got through alive.

The bullet was made of silver, so that the spy could

swallow it without injury from corrosion. . . .

Almost as soon as he started, Taylor was captured.

. .. Realizing his peril too late, the spy fell into a

paroxysm of terror and crying, “I am lost,” swallowed the silver bullet. Administration of a strong

emetic soon produced the bullet with fatal results,

for Taylor was executed. “A rather heartless

American joke went around,” adds Bakeless, “that

Taylor had been condemned ‘out of his own

mouth’.”

We next see (fig. 41) one Benedict Arnold message that was never deciphered. It is often referred

to as “Benedict Arnold’s Treasonable Cow Letter.”

Only one example is extant; certain words have

purely arbitrary meanings, as prearranged. The letter was written just two weeks before the capture of

Major André.

In figure 42, we see a British cipher message of

the vintage 1781. It was deciphered before finding

the key, always a neat trick when or if you can do it.

The key – the title page of the then current British

Army List – is shown in figure 43. The numbers in

the cipher text obviously refer to line numbers and

letter numbers in the line of a key text, the first

series of numbers, viz., 22.6.7.39.5.9.17, indicating

line number 22, letter numbers 6.7.39.5.9.17 in that 

Fig. 39
Page 40

Fig. 40

Fig. 41 Fig. 42
Page 41

line. Because of so many repetitions, the plain text

was obtained by straightforward analysis by an officer recently on duty in NSA, Captain Edward W.

Knepper, USN, to whom I am indebted for this

interesting example. The plain text, once obtained,

gave him clues as to what the key text might be,

simply by placing the plaintext letters in their

numerical-equivalent order in the putative key text.

This done, Captain Knepper was quick to realize

what the key text was – a British Army List. The

date of the message enabled him to find the list

without much difficulty in the Library of Congress

(fig. 43).

There was an American who seems to have been

the Revolution’s one-man National Security

Agency, for he was the one and only cryptologic

expert Congress had, and, it is claimed, he managed

to decipher nearly all, if not all, of the British code

messages obtained in one way or another by the

Americans. Of course, the chief way in which

enemy messages could be obtained in those days

was to capture couriers, knock them out or knock

them off, and take the messages from them. This

was very rough stuff, compared to getting the material by radio intercept, as we do nowadays.

I think you’ll be interested to hear a bit more

about that one-man NSA. His name was James

Lovell, and besides being a self-trained cryptologist, he was also a member of the Continental

Congress. There’s on record a very interesting letter

he wrote to General Nathaniel Greene, with a copy

to General Washington. Here it is.

Philadelphia, Sept. 21, 1781

Sir:

You once sent some papers to Congress

which no one about you could decypher.

Should such be the Case with some you

have lately forwarded I presume that the

Result of my pains, here sent, will be useful to you. I took the Papers out of

Congress, and I do not think it necessary to

let it be known here what my success has

been in the attempt. For it appears to me

that the Enemy make only such Changes in

their Cypher, when they meet with misfortune, as makes a difference of Position

only to the same Alphabet, and therefore if

no talk of Discovery is made by us here or

by your Family, you may be in Chance to

draw Benefit this Campaign from my last

Night’s Watching.

I am Sir with much respect,

Your Friend,

JAMES LOVELL

Maj. Genl. Greene

(With copy to Genl. Washington)

In telling you about Lovell, I should add to my

account of that interesting era in cryptologic history an episode I learned about only recently. When a

certain message of one of the generals in command

of a rather large force of colonials came into

Clinton’s possession, he sent it off posthaste to

London for solution. Of course, Clinton knew it was

going to take a lot of time for the message to get to

London, be solved and returned to America – and

he was naturally a bit impatient. He felt he couldn’t

afford to wait that long. Now it happened that in his

command were a couple of officers who fancied

themselves to be cryptologists, and they undertook

to solve the message, a copy of which had been

Fig. 43
Page 42

made before sending the original off to London.

Well, they gave Sir Henry their solution, and he

acted upon it. The operation turned out to be a dismal failure, because the solution of the would-be

cryptanalysts happened to be quite wrong! The

record doesn’t say what Clinton did to those two

unfortunate cryptologists when the correct solution

arrived from London some weeks later. By the way,

you may be interested in learning that the British

operated a regularly established cryptanalytic

bureau as early as 1630, and it continued to operate

until the end of July 1844. Then there was no such

establishment until World War I. I wish there were

time to tell you some of the details of that fascinating and little known bit of British history.

There’s also an episode I learned about only

very recently, which is so amusing I ought to share

it with you. It seems that a certain British secret

agent in America was sent a message in plain

English, giving him instructions from his superior.

But the poor fellow was illiterate, and there wasn’t

anything to do but call upon the good offices of a

friend to read it to him. He found such a friend, who

helped him read his instructions. What he didn’t

know, however, was that the friend who’d helped

him was one of General Washington’s secret

agents!

The next illustration (fig. 44) is a picture of one

of several syllabaries used by Thomas Jefferson. It

is constructed on the so-called two-part principle,

which was explained in the preceding lecture.

Figure 44a is a portion of the encoding section, and

figure 44b is a portion of the decoding section, in

which the code equivalents are in numerical order

accompanied by their meanings as assigned them

in the encoding section. This sort of system, which,

as I’ve already explained, was quite popular in colonial times as in the early days of Italian cryptography, is still in extensive use in some parts of the

world.

A few minutes ago I mentioned Benjamin

Franklin’s cipher system, which, if used today,

would be difficult to solve, especially if there were

only a small amount of traffic in it. Let me show you

what it was. Franklin took a rather lengthy passage

from some book in French and numbered the letters successively. These numbers then became

equivalents for the same letters in a message to be

sent. Because the key passage was in good French,

naturally there were many variants for the letter E

– in fact, there were as many as one would expect in

normal plaintext French; the same applied to the

other high-frequency letters such as R, N, S, I, etc.

What this means, of course, is that the high-frequency letters in the plain text of any message to be

enciphered could be represented by many different

numbers, and a solution on the basis of frequency

and repetitions would be very much hampered by

the presence of many variant values for the same

plaintext letter. In figure 45 you can see this very

clearly.

Fig. 44a

Fig. 44b
Page 43

I know of but one case in all U.S. history in

which a resolution of Congress was put out in cryptographic form. It is shown in figure 46 – a resolution of the Revolutionary Congress dated 8

February 1782. I have in my collection not only a

copy of the resolution but also a copy of the syllabary by which it can be deciphered.

Interest in cryptology in America seems to have

died with the passing of Jefferson and Franklin. But

if interest in cryptology in America wasn’t very

great, if it existed at all after the Revolution, this

was not the case in Europe. Books on the subject

were written, not by professionals, perhaps, but by

learned amateurs, and I think you will find some of

them in the NSA library if you’re interested in the

history of the science. The next illustration (fig. 47)

is the frontispiece of a French book the title of

which (translated) is Counter-espionage, or keys

for all secret communications. It was published in

Paris in 1793. In the picture, we see Dr. Cryppy

himself, and perhaps a breadboard model of a GS11 research analyst, or maybe an early model of a

WAC.

I am now going to tell you something about the

early steps in finding an answer to the age-old mystery presented by Egyptian hieroglyphics, not only

because I think that the solution represents the next

landmark in the history of cryptology, but also

because the story is of general interest to any aspiring cryptologist. About 1821 a Frenchman,

Champollion, startled the world by beginning to

publish translations of Egyptian hieroglyphics,

although in the budding new field of Egyptology

much had already transpired and been published.

In figure 48 we see the gentleman and in figure 49,

a picture of the great Napoleonic find that certainly

facilitated and perhaps made possible the solution

of the Egyptian hieroglyphic writing – the Rosetta

Stone. A The Rosetta Stone was found in 1799 at

Rashid, or as the Europeans called it, Rosetta, a

town in northern Egypt on the west bank of the

Rosetta branch of the Nile.

Rosetta was in the vicinity of Napoleon’s operations that ended in disaster. When the peace treaty

was written, Article 16 of it required that the

Rosetta Stone, the significance of which was quickly understood by both the conquered French and

victorious British commanders, be shipped to

London, together with certain other large antiquities. The Rosetta Stone still occupies a prominent

place in the important exhibits at the British

Museum. The Rosetta Stone is a bilingual inscription, because it is in Egyptian and also in Greek. 

Fig. 45
Page 44

The Egyptian portion consists of two parts, the

upper one in hieroglyphic form, the lower one in a

sort of cursive script, also Egyptian, but called

“Demotic.” It was soon realized that all three texts

were supposed to say the same thing, of course, and

since the Greek could easily be read, it served as

something called in cryptanalysis a “crib.” Any time

you are lucky

enough to find a

crib, it saves you

hours of work. It

was by means of

this bilingual

inscription that the

Egyptian hieroglyphic writing was

finally solved, a feat

that represented

the successful solution to a problem

the major part of

which was linguistic in character. The cryptanalytic

part of the task was relatively simple. Nevertheless,

I think that anyone who aspires to become a professional cryptologist should have some idea as to

what that cryptanalytic feat was, a feat that some

professor (but not of cryptologic service; I think it

was Professor Norbert Wiener of the Massachusetts

Institute of Technology) said was the greatest cryptanalytic feat in history. We shall see how wrong the

good professor was, because I’m going to demonstrate just what the feat really amounted to by

showing you some simple pictures.

First, let me remind you that the Greek text

served as an excellent crib for the solution of both

Egyptian texts, the hieroglyphic and the Demotic,

the latter merely being the conventional abbreviated and modified form of the Hieratic character or

cursive form of hieroglyphic writing that was in use

in the Ptolemaic Period.

The initial step was taken by a Reverend

Stephen Weston, who made a translation of the

Greek inscription, which he read in a paper delivered before the London Society of Antiquaries in

April 1802.

In 1818 Dr. Thomas Young, the physicist who

first proposed the wave theory of light, compiled for

the fourth volume of Encyclopaedia Britannica,

published in 1819, the results of his studies on the

Rosetta Stone; among them was a list of several

Fig. 47

Fig. 46

Fig. 48
Page 45

Fig. 49
Page 46

Egyptian characters to which, in most cases, he had

assigned correct phonetic values. He was the first

to grasp the idea of a phonetic principle in the

Egyptian hieroglyphs, and he was the first to

apply it to their decipherment. He also proved

something that others had only suspected, namely,

that the hieroglyphs in ovals or cartouches were

royal names. But Young’s name is not associated in

the public mind with the decipherment of Egyptian

hieroglyphics – that of Champollion is very much

so. Yet much of what Champollion did was based

upon Young’s work. Perhaps the greatest credit

should go to Champollion for recognizing the major

importance of an ancient language known as Coptic

as a bridge that could lead to the decipherment of

the Egyptian hieroglyphics. As a lad of seven, he’d

made up his mind that he’d solve the hieroglyphic

writing, and in the early years of the nineteenth

century he began to study Coptic. In his studies of

the Rosetta Stone, his knowledge of Coptic, a language the knowledge of which had never been lost,

enabled him to deduce the phonetic value of many

syllabic signs and to assign correct readings to

many pictorial characters, the meanings of which

became known to him from the Greek text on the

Stone.

The following step-by-step account of the solution is taken from a little brochure entitled The

Rosetta Stone, published by the Trustees of the

British Museum. It was written in 1922 by E.A.

Wallis Budge and was revised in 1950. I quote:

The method by which the greater part of

the Egyptian alphabet was recovered is

this: It was assumed correctly that the

oval, or ‘cartouche’ as it is called, always

contained a royal name. There is only one

cartouche (repeated six times with slight

modifications) on the Rosetta Stone, and

this was assumed to contain the name of

Ptolemy, because it was certain from the

Greek text that the inscription concerned a

Ptolemy. It was also assumed that if the

cartouche did contain the name of

Ptolemy, the characters in it would have

the sounds of the Greek letters, and that all

together they would represent the Greek

form of the name of Ptolemy. Now on the

obelisk which a certain Mr. Banks had

brought from Philae there was also an

inscription in two languages, Egyptian and

Greek. In the Greek portion of it two royal

names are mentioned, that is to say,

Ptolemy and Cleopatra, and on the second

face of the obelisk there are two cartouches, which occur close together, and are

filled with hieroglyphs which, it was

assumed, formed the Egyptian equivalents

of these names. When these cartouches

were compared with the cartouche on the

Rosetta Stone it was found that one of

them contained hieroglyphic characters

that were almost identical with those

which filled the cartouche on the Rosetta

Stone. Thus there was good reason to

believe that the cartouche on the Rosetta

Stone contained the name of Ptolemy written in hieroglyphic characters. The forms

of the cartouches are as follows:

On the Rosetta Stone: 

On the Obelisk from Philae:

In the second of these cartouches a single

sign takes the place of three signs at the

end of the first cartouche. Now it has

already been said that the name of

Cleopatra was found in Greek on the

Philae Obelisk, and the cartouche that was

assumed to contain the Egyptian equivalent to this name appears in this form:
Taking the cartouches which were supposed to contain the names of Ptolemy and

Cleopatra from the Philae Obelisk, and

numbering the signs we have:

Ptolemy, A.

Cleopatra, B. 

Now we see at a glance that No.1 in A and

No.5 in B are identical, and judging only by

their position in the names, they must represent the letter P. No.4 in A and No.2 in B

are identical, and arguing as before from

their position, they must represent the letter L. As L is the second letter in the name

of Cleopatra, sign No.1 in B must represent

K. In the cartouche of Cleopatra, we now

know the values of Signs Nos. 1,2 and 5, so

we may write them down thus:

In the Greek form of the name Cleopatra,

there are two vowels between the land P,

and in the hieroglyphic form there are two

hieroglyphs, 

so we may assume that the first is E and the

other O. In some forms of the cartouche of

Cleopatra, No. 7 (the hand) is replaced by a

half circle, which is identical with No.2 in A

and No. 10 in B. As T follows P in the name

Ptolemy, and as there is a T in the Greek

form of the name of Cleopatra, we may

assume that the half circle and the hand

have substantially the same sound, and

that that sound is T. In the Greek form of

the name Cleopatra, there are two A’s, the

position of which agree with No.6 and

No.9, and we may assume that the bird has

the value of A. Substituting these values

for the hieroglyphs in B we may write it

thus:

Thomas Young noticed that the two signs 

always followed the name for a goddess, or

queen, or princess. Other early decipherers regarded the two signs as a mere feminine termination. The only sign for which

we have no phonetic equivalent is No.8,

the lens, and it is obvious that this must

represent R. Inserting this value in the cartouche, we have the name Cleopatra deciphered. Applying now the values that we

have learned from the cartouche of

Cleopatra to the cartouche of Ptolemy we

may write it thus:

We now see that the cartouche must be

that of Ptolemy, but it is also clear that

there must be contained in it many other

hieroglyphs which do not form part of his

name. Other forms of the cartouche of

Ptolemy are found, even on the stone, the

simplest of them written thus:

and

Page 47

this

and this,
Page 48

It was therefore evident that these other

signs were royal titles corresponding to

those found in the Greek text on the

Rosetta Stone

meaning ‘everliving, beloved

of Ptah.’ Now the Greek form of the name

Ptolemy, i.e., Ptolemaios, ends with S. We

may assume therefore that the last sign

in the simplest form of the cartouche

given above has the phonetic value of S.

The only hieroglyphs now doubtful are 

and their position in the name of Ptolemy

suggests that their phonetic values must be

M and some vowel sound in which the I

sound predominates. These values, which

were arrived at by guessing and deduction,

were applied by the early decipherers to

other cartouches, e.g.:

Now in No.1, we can at once write down the

values of all the signs, viz., P. I. L. A. T. R.

A., which is obviously the Greek name

Philotera. In No.2 we know only some of

the hieroglyphs, and we write the cartouche thus:

It was known that the running water sign

occurs in the name Berenice, and

that it represents N, and that this sign

is the last word of the transcript of the

Greek title “Kaisaros,” and therefore represent some S sound. Some of the forms of

the cartouche of Cleopatra begin with

, and it is clear that its phonetic value

must be K. Inserting these values in the

cartouche above we have:

which is clearly meant to represent the

name “Alexandros,” or Alexander. The

position of this sign

represented some sound of E or A.

Well, I’ve shown you enough to make fairly

clear what the problem was and how it was solved.

As you may have already gathered, the cryptanalysis was of a very simple variety.

The grammar? Well, that’s an entirely different

story: there’s where the difficult part lay. It was very

fortunate that the first attacks on Egyptian hieroglyphics didn’t have to deal with enciphered writing. Yes, the Egyptians also used cryptography; yes,

there are “cryptographic hieroglyphics”! We’ll get to

these later, but at this point it may be of interest to

many of you to learn something about what the

Rosetta Stone had to say, as set forth by Dr. Budge:

The opening lines are filled with a list of

the titles of Ptolemy V, and a series of epithets which proclaim the king’s piety

towards the gods, and his love for the

Egyptians and his country. In the second

section of the inscription the priests enumerate the benefits which he had conferred upon Egypt and which may thus be

summarized:

1. Gifts of money and corn to the temples.

2. Gifts of endowments to temples.

3. Remission of taxes due to the Crown.

4. Forgiveness of debts owed by the people

to the Crown.

______________________________

7. Reduction of fees payable by candidates

for the priesthood.

8. Reduction of the dues payable by the

temples to the Crown.

______________________________

13. Forgiveness of the debts owed by the

priests to the Crown.

and

shows that it
Page 49

Fig. 50a

Fig. 50b
Page 50

14. Reduction of the tax on byssus (a kind

of flax or cotton fibre).

15. Reduction of the tax on corn lands.

Could it be that installment-plan buying was

rampant in ancient Egypt too, so that people didn’t

have enough left to pay their taxes?

Now, let’s go back to those cryptographic hieroglyphics mentioned a moment ago. Here, in figure

50a, for instance, is a picture of an inscription on a

stela now in the Louvre, in Paris. Lines 6-10, inclusive, below the seated figures under the arch, contain secret writing in hieroglyphics; in figure 50b,

these lines are seen enlarged. I won’t attempt to

explain the nature of the cryptography involved. It’s

pretty simple – something like the sort of cryptography involved in our own type of rebuses, and in

our modern acronymic abbreviations, such as

CARE (Cooperative for American Relief

Everywhere) or NASA (National Aeronautics and

Space Administration).

The following extracts, translated from a long

article by Professor Étienne Drioton in “Revue

D’Égyptologie,” Paris, 1933, will be of interest (p. 1):

From the time of the Middle Empire

onwards, Egypt had, alongside the official

and normal system of writing, a tradition

of cryptographic writing, the oldest known

examples of which are to be found in the

tombs of Beni-Hassan, and the most

recent in the inscriptions of the temples of

the Greco-Roman epoch.

* * * * * * *

(p.32):

It is necessary to add to the enumeration of

the cryptographic procedures the variation in the appearance of the cryptographic signs themselves. . . . This variation,

without however affecting their value, can

(1) modify the appearance of the signs; (2)

affect their position in various ways; and

(3) combine these signs with others. . . .

Finally. to note a last peculiarity of these

inscriptions which, because of their fine

form, deserve to be considered the classics

of the cryptography of this period, the

scribe has several times successfully carried out in them what was doubtless considered to be the triumph of the genre: the

grouping of signs which offer a possible

but fallacious meaning in clear, alongside

a cryptographic meaning which is the only

true one.

And now for the most intriguing explanation

offered by Drioton as to why cryptography was

incorporated in these inscriptions. You know quite

well why cryptography is employed in military,

diplomatic, banking, and industrial affairs; you also

know perhaps that it is used for other purposes, in

love affairs, for example, and in illicit enterprises of

all sorts; and you probably also know that it is often

used for purposes of amusement and diversion, in

tales of mystery, in the sorts of things published in

newspapers and literary journals – they are called

“crypts.” But none of these explanations will do for

the employment of cryptography in Egyptian hieroglyphics. Here’s what Drioton thinks:

(p.50):

There remains, therefore, the supposition

that, far from seeking to prevent reading,

the cryptography in certain passages of

these inscriptions was intended to encourage their reading.

The appeals which often introduce formulae of this type, and which are addressed to

all visitors to the tombs, show in fact how

much the Egyptians desired to have them

read, but also, by the very fact of their existence, what an obstacle they encountered

in the indifference, not to say satiety, produced by the repetition and the monotony

of these formulae. To attempt to overcome

this indifference by offering a text whose

appearance would pique curiosity, based

on the love, traditional in Egypt, for puzzles, to get people to decipher, with great
Page 51

difficulty, what was desired they should

read, such is perhaps, in last analysis, the

reason why the three monuments of the

period of Amenophis III here considered

present certain passages in cryptography.

One must suppose, in this case, that the

goal was not attained and that it was very

quickly seen that the expedient produced,

on the apathy of the visitors, an effect

opposite to that intended: it removed even

the slightest desire to read the inscriptions

presented in this form. The new procedure

was therefore – the monuments seem to

prove it – abandoned as soon as it had

been tried.

* * * * * *

Before leaving the story of Champollion’s mastery of Egyptian hieroglyphic writing, I think I

should reenact for you as best I can in words what

he did when he felt he’d really reached the solution

to the mystery. I’ll preface it by recalling to you

what Archimedes is alleged to have done when he

solved a problem he’d been struggling with for

some time. Archimedes was enjoying the pleasures

of his bath and was just stepping out of the pool

when the solution of the problem came to him like

a flash. He was so overjoyed that he ran, naked,

through the streets shouting, “Eureka! I’ve found it,

I’ve found it.” Well, likewise, when young

Champollion one day had concluded he’d solved

the mystery of the Egyptian hieroglyphics, he set

out on a quick mile-run to the building where his

lawyer brother worked, stumbled into his brother’s

office, shouting “Eugene, I did it!” and flopped

down to the floor in a trance where he is said to

have remained immobile and completely out for

five days. “Champollion died on 4 March 1832,

leaving behind the manuscript of an Egyptian

Grammar and of a Hieroglyphic Dictionary,

which, except for some errors of details inevitable

in a gigantic work of decipherment and easily correctable, form the basis of the entire science of

Egyptology.”1

I shouldn’t leave this brief story of the cryptanalytic phases of the solution of the Egyptian hieroglyphic writing without telling you that there

remain plenty of other sorts of writings that some of

you may want to try your hand at deciphering when

you’ve learned some of the principles and procedures of the science of cryptology. A list of nineteen

thus-far undeciphered writings was drawn up for

me by Professor Alan C. Ross, of London

University, in 1945. Since 1945 only two have been

deciphered, Minoan Linear A and Linear B writing.

The Easter Island writing is said to have very

recently been solved, but I’m not sure of that. There

are some, maybe just a very few, who think the

hieroglyphic writing of the ancient Maya Indians of

Central America may fall soon, but don’t be too sanguine about that either.

Should any of you be persuaded to tackle any 

of the still undeciphered writings in the list drawn

up by Professor Ross, be sure you have an authentic case of an undeciphered language before you.

Figure 51 is one that was written on a parchment

known as the Michigan Papyrus. It had baffled 

certain savants who had a knowledge of 

Egyptology and attempted to read it on the theory

that it was some sort of variation – a much later

modification – of Egyptian hieroglyphic writing.

These old chaps gave it up as a bad job. Not too

many years ago, it came to the attention of a young

man who knew very little about Egyptian hieroglyphics. He saw it only as a simple substitution

cipher on some old language. He tackled the

Michigan Papyrus on that basis and solved it. He

found the language to be early Greek. And what 

was the purport of the writing? Well, it was a wonderful old Greek beautician’s secret formula for further beautifying lovely Greek young women –

maybe the bathing beauties of those days, among

whom possibly were “Miss Greece of 500 B.C.” and

“Miss Universe” of those days!
Page 52

The next period of importance in this brief

account of the history of cryptology is the one that

deals with the codes and ciphers used by the contestants in our Civil War, the period 1861-65. It is

significant and important because for the first time

in history, rapid and secure communications on a

large scale became practicable in the conduct of

organized warfare and worldwide diplomacy. They

became practicable when cryptology and telegraphy were joined in happy, sometimes contentious,

but long-lasting wedlock. There is one person I

should mention, however, before coming to the

Civil War. I refer here to Edgar Allan Poe, who in

1842 or thereabouts kindled an interest in cryptography in newspapers and journals of the period,

both at home and abroad. For his day he was certainly the best informed person in this country on

cryptologic matters outside of the regular employees of government departments interested in the

subject.

In regard to Poe, one of our early columnists,

there’s an incident I’d like to tell you about in connection with a challenge he printed in one of his

columns, in which he offered to solve any cipher

submitted by his readers. He placed some limitations on his challenge, which amounted to this –

that the challenge messages should involve but a

single alphabet. In a later article Poe tells about the

numerous challenge messages sent him and says:

“Out of perhaps 100 ciphers altogether received,

there was only one which we did not immediately

succeed in resolving. This one we demonstrated to

be an imposition – that is to say, we fully proved it

a jargon of random characters, having no meaning

whatever.” I wish that cipher had been preserved

for posterity because it would be interesting to see

what there was about it that warranted Poe to say

that “we fully proved it a jargon of random characters.” Maybe I’m not warranted in saying of this

episode that Poe reminds me of a ditty sung by a

character in a play put on by some undergraduates

of one of the colleges of Cambridge University in

England. At a certain point in the play, the character steps to the front of the stage and sings

I am the Master of the College,

What I don’t know ain’t knowledge.

Thus, Poe. What he couldn’t solve, he assumed wasn’t a real cipher – a very easy out for any cryptologist up against something tough.

If any of you are interested sufficiently to wish

to learn something about Poe’s contributions to

cryptology, I refer you to a very fine article by

Professor W.K. Wimsatt, Jr., entitled “What Poe

Knew About Cryptography,” Publications of the

Modern Language Association of America, New

York, Vol. LVIII, No.3, September 1943, 754-79. In

it you’ll find references to what I have published on

the same subject.

This completes the third lecture in this series. In

the next one we shall come to that interesting period in cryptologic history in which codes and ciphers

were used in this country in the War of the

Rebellion, the War Between the States, the Civil

War – you use your own pet designation for that

terrible and costly struggle.

Fig. 51
Page 53

NOTES

1. Drioton, “Decipherment of Egyptian

Hieroglyphics,” La Science Moderne, August 1924, 423-

32.
Page 54
Page 55

A detailed account of the codes and ciphers of

the Civil War of the United States of America can

hardly be told without beginning with a bit of biography about the man who became the first signal

officer in history and the first Chief Signal Officer of

the United States Army, Albert J. Myer, the man in

whose memory that lovely little U.S. Army post

adjacent to Arlington Cemetery was named. Myer

was born on 20 September 1827, and after an

apprenticeship in the then quite new science of

electric telegraphy he entered Hobart College,

Geneva, New York, from which he was graduated in

1847. From early youth he had exhibited a predilection for artistic and scientific studies, and upon

leaving Hobart he entered Buffalo Medical College,

receiving the M.D. degree four years later. His graduation thesis, “A Sign Language for Deaf Mutes,”

contained the germ of the idea he was to develop

several years later, when in 1854 he was commissioned a first lieutenant in the regular army, made

an assistant surgeon, and ordered to New Mexico

for duty. He had plenty of time at this faraway outpost to think about developing an efficient system

of military “aerial telegraphy,” which was what

visual signaling was then called. I emphasize the

word “system” because, strange to say, although

instances of the use of lights and other visual signals can be found throughout the history of warfare, and their use between ships at sea had been

practiced by mariners for centuries, down to the

middle of the nineteenth century surprisingly little

progress had been made in developing methods

and instruments for the systematic exchange of

military information and instructions by means of

signals of any kind. Morse’s practical system of

electric telegraphy, developed in the years 1832-35,

served to focus attention within the military upon

systems and methods of intercommunication by

means of both visual and electrical signals. In the

years immediately preceding the Civil War, the U.S.

Army took steps to introduce and to develop a system of visual signaling for general use in the field. It

was Assistant Surgeon Myer who furnished the initiative in this matter.

In 1856, two years after he was commissioned

assistant surgeon, Myer drafted a memorandum on

a new system of visual signaling and obtained a

patent on it. Two years later, a board was appointed by the War Department to study Myer’s system.

It is interesting to note that one of the officers who

served as an assistant to Myer in demonstrating his

system before the board was a Lieutenant E.P.

Alexander, Corps of Engineers. We shall hear more

about him presently, but at the moment I will say

that on the outbreak of war, Alexander organized

the Confederate Signal Corps. After some successful demonstrations by Myer and his assistants, the

War Department fostered a bill in Congress, which

Lecture IV

Fig. 52. Brigadier General Albert J. Myer
Page 56

gave its approval to his ideas. But what is more to

the point, Congress appropriated an initial amount

of $2,000 to enable the Army and the War

Department to develop the system. The money, as

stated in the act, was to be used “for manufacture or

purchase of apparatus and equipment for field signaling.” The act also contained another provision: it

authorized the appointment on the Army staff of

one signal officer with the rank, pay, and

allowances of a major of cavalry. On 2 July 1860,

“Assistant Surgeon Albert J. Myer (was appointed)

to be Signal Officer, with the rank of Major, 27 June

1860, to fill an original vacancy,” and two weeks

later Major Myer was ordered to report to the commanding general of the Department of New Mexico

for signaling duty. The War Department also directed that two officers be detailed as his assistants.

During a several months’ campaign against hostile

Navajos, an extensive test of Myer’s new system,

using both flags and torches, was conducted with

much success. In October 1860, a Lieutenant J.E.B.

Stuart, later to become famous as a Confederate

cavalry leader, tendered his services to aid in signal

instruction.

Less than a year after Major Myer was appointed as the first and, at that time, the only signal officer of the U.S. Army, Fort Sumter was attacked, and

after a thirty-six-hour bombardment, it surrendered. The bloody four-year war between the North

and the South had begun. The date was 14 April

1861. Myer’s system of aerial telegraphy was soon

to undergo its real baptism under fire, rather than

by fire. But with the outbreak of war, another new

system of military signal communication, signaling

by the electric telegraph, began to undergo its first

thorough test in combat operations. This in itself is

very important in the history of cryptology. But far

more significant in that history is a fact I mentioned

at the close of the last lecture, viz, that for the first

time in the conduct of organized warfare, rapid and

secret military communications on a large scale

became practicable, because cryptology and electric telegraphy were now to be joined in lasting

wedlock. For when the war began, the electric telegraph had been in use for less than a quarter of a

century. Although the first use of electric telegraphy

in military operations was in the Crimean War in

Europe (1854-56), its employment was restricted to

communications exchanged among headquarters

of the Allies, and some observers were very doubtful about its utility even for this limited usage. It

may also be noted that in the annals of that war

there is no record of the employment of electric

telegraphy together with means for protecting the

messages against their interception and solution by

the enemy.

On the Union side in the Civil War, military signal operations began with Major Myer’s arrival in

Washington on 3 June 1861. His basic equipment

consisted of kits containing a white flag with a red

square in the center for use against a dark background, a red flag with a white square for use

against a light background, and torches for night

use. It is interesting to note that these are the elements that make up the familiar insignia of our

Army Signal Corps. The most pressing need that

faced Major Myer was to get officers and men

detailed to him wherever signals might be required,

and to train them in what had come to be called the

“wig-wag system,” the motions of which are depicted in figure 53. This training included learning

something about codes and ciphers and gaining

experience in their use.

But there was still no such separate entity as a

Signal Corps of the Army. Officers and enlisted men

were merely detailed for service with Major Myer

for signaling duty. It was not until two years after

the war started that the Signal Corps was officially

established and organized as a separate branch of

the Army, by appropriate congressional action.

In the meantime, another signaling organization was coming into being – an organization that

was an outgrowth of the government’s taking over

control of the commercial telegraph companies in

the United States on 25 February 1862. There were

only three: the American, the Western Union, and

the Southwestern. The telegraph lines generally followed the right-of-way of the railroads. The then
Page 57

secretary of war, Simon Cameron, sought the aid of

Thomas A. Scott of the Pennsylvania Railroad, who

brought some of his men to Washington for railroad and telegraphic duties with the federal government. From a nucleus of four young telegraph

operators grew a rather large military telegraph

organization that was not given formal status until

on 28 October 1861 President Lincoln gave

Secretary Cameron authority to set up a “U.S.

Military Telegraph Department” under a man

named Anson Stager, who, as a general superintendent of the Western Union, was called to

Washington, commissioned a captain (later a

colonel) in the Quartermaster Corps, and made

superintendent of the Military Telegraph

Department. Only about a dozen of the members of

the department became commissioned officers,

and they were made officers so that they could

receive and disburse funds and property; all the rest

were civilians. The U.S. Military Telegraph “Corps,”

as it soon came to be designated, without warrant,

was technically under Quartermaster General

Meigs, but for all practical purposes it was under

the immediate and direct control of the secretary of

war, a situation admittedly acceptable to Meigs.

There were now two organizations for signaling in

the Army, and it has hardly to be expected that no

difficulties would ensue from the duality. In fact,

the difficulties began very soon, as can be noted in

the following extract from a lecture before the

Washington Civil War Round Table, early in 1954,

by Dr. George R. Thompson, Chief of the Historical

Division of the Office of the Chief Signal Officer of

the U.S. Army:

The first need for military signals arose at

the important Federal fortress in the lower

Chesapeake Bay at Fort Monroe. Early in

June, Myer arrived there, obtained a detail

of officers and men and began schooling

them. Soon his pupils were wig-wagging

messages from a small boat, directing fire

of Union batteries located on an islet in

Hampton Roads against Confederate fortifications near Norfolk. Very soon, too,

Myer began encountering trouble with

commercial wire telegraphers in the area.

General Ben Butler, commanding the

Federal Department in southeast Virginia,

ordered that wire telegraph facilities and

their civilian workers be placed under the

signal officer. The civilians, proud and

jealous of their skills in electrical magic,

objected in no uncertain terms and shortly

an order arrived from the Secretary of

War himself who countermanded Butler’s

instructions. The Army signal officer was

to keep hands off the civilian telegraph

even when it served the Army.

I have purposely selected this extract from Dr.

Thompson’s presentation because in it we can

clearly hear the first rumblings of that lengthy and

acrimonious feud between two signaling organizations whose uncoordinated operations and rivalry

Fig. 53
Page 58

greatly reduced the efficiency of all signaling operations of the Federal army. As already indicated, one

of these organizations was the U.S. Military

Telegraph “Corps,” hereinafter abbreviated as the

USMTC, a civilian organization that operated the

existing commercial telegraph systems for the War

Department, under the direct supervision of the

secretary of war, Edwin M. Stanton. The other

organization was, of course, the infant Signal Corps

of the United States Army, which was not yet even

established as a separate branch, whereas the

USMTC had been established in October 1861, as

noted above. Indeed, the Signal Corps had to wait

until March 1863, two years after the outbreak of

war, before being established officially. In this connection it should be noted that the Confederate

Signal Corps had been established a full year earlier, in April 1862. Until then, as I’ve said before, for

signaling duty on both sides, there were only officers who were individually and specifically detailed

for such duty from other branches of the respective

armies of the North and the South. Trouble

between the USMTC and the Signal Corps of the

Union army began when the Signal Corps became

interested in signaling by electric telegraphy and

began to acquire facilities therefor.

As early as June 1861, Chief Signal Officer Myer

had initiated action toward acquiring or obtaining

electrical telegraph facilities for use in the field, but

with one exception nothing happened. The exception was the episode in the military department in

southeast Virginia, commanded by General

Benjamin Butler, an episode that clearly foreshadowed the future road for the Signal Corps in regard

to electrical signaling: the road was to be closed and

barred. In August 1861 Colonel Myer tried again,

and in November of the same year he recommended in his annual report that $30,000 be appropriated to establish an electric signaling branch in the

Signal Corps. The proposal failed to meet the

approval of the secretary of war. One telegraph

train, however, that had been ordered by Myer

many months before, was delivered in January

1862. The train was tried out in an experimental

fashion, and under considerable difficulties, the

most disheartening of which was the active opposition of persons of Washington, particularly the secretary of war. So, for practically the whole of the

first two years of the war, signal officers on the

Northern side had neither electrical telegraph facilities nor Morse operators – they had to rely entirely on the wig-wag system. However, by the middle

of 1863 there were thirty “flying telegraph” trains in

use in the Federal army. Here’s a picture (fig. 54) of

such a train. The normal length of field telegraph

lines was five to eight miles, though in some cases

the instruments had worked at distances as great as

twenty miles. But even before the Signal Corps

began to acquire these facilities, there had been agitation to have them, as well as their Signal Corps

operating personnel, all turned over to the USMTC,

which had grown into a tightly knit organization of

over 1,000 men and had become very influential in

Washington, especially by virtue of its support from

Secretary of War Stanton. As a consequence, the

USMTC had its way. In the fall of 1863, it took over

all the electric telegraph facilities and telegraph

operators of the Signal Corps. Colonel Myer sadly

wrote: “With the loss of its electrical lines the Signal

Corps was crippled.”

So now there were two competing signal organizations on the Northern side: the U.S. Army’s

Signal Corps, which was composed entirely of military personnel with no electric telegraph facilities

(but was equipped with means for visual signaling),

and the USMTC, which was not a part of the Army,

being staffed almost entirely with civilians, and that

had electric telegraph facilities and skilled Morse

operators (but no means or responsibilities for

visual signaling or “aerial telegraphy” that, of

course, was old stuff). “Electric telegraphy” was

now the thing. The USMTC had no desire to share

electric telegraphy with the Signal Corps, a determination in which it was most ably assisted by

Secretary of War Stanton, for reasons that fall outside the scope of the present lecture.

However, from a technical point of view it is

worth going into this rivalry just a bit, if only to note

that the personnel of both organizations, the mili-
Page 59

tary and the civilian, were not merely signalmen

and telegraph operators: they served also as cryptographers and were therefore entrusted with the

necessary cipher books and cipher keys. Because of

this, they naturally became privy to the important

secrets conveyed in cryptographic communications, and they therefore enjoyed status as VIPs.

This was particularly true of members of the

USMTC, because they, and only they, were authorized to be custodians and users of the cipher books.

Not even the commanders of the units they served

had access to them. For instance, on the one and

only occasion when General Grant forced his cipher

operator, a civilian named Beckwith, to turn over

the current cipher book to a colonel on Grant’s staff,

Beckwith was immediately discharged by the secretary of war, and Grant was reprimanded. A few days

later Grant apologized, and Beckwith was restored

to his position. But Grant never again demanded

the cipher book held by his telegraph operator.

The Grant-Beckwith affair alone is sufficient to

indicate the lengths to which Secretary of War

Stanton went to retain control over the USMTC,

including its cipher operators and its cipher books.

In fact, so strong a position did he take that on 10

November 1863, following a disagreement over

who should operate and control all the military telegraph lines, Myer, by then full colonel and bearing

the imposing title “Chief Signal Officer of the

United States Army,” a title he had enjoyed for only

two months, was peremptorily relieved from that

position and put on the shelf. Not long afterward,

and for a similar reason, Myer’s successor,

Lieutenant Colonel Nicodemus, was likewise summarily relieved as Chief Signal Officer by Secretary

Stanton; indeed, he was not only removed from

that position – he was “dismissed from the

Service.” Stanton gave “phony” reasons for dismissing Colonel Nicodemus, but I am glad to say that

the latter was restored his commission in March

1865 by direction of the president; also by direction

of the president, Colonel Myer was restored to his

position as Chief Signal Officer of the U.S. Army on

25 February 1867.

When Colonel Myer was relieved from duty as

Chief Signal Officer in November 1863, he was

Fig. 54. A drawing from Myer’s Manual of Signals illustrating the field, or flying, telegraph. It

shows the wagon with batteries and instruments. The wire (in this case presumably bare copper, since it is being strung on insulators on poles) is being run out from a reel carried by two

men. The linemen are using a crowbar to open holes to receive the lance poles. Myer estimated

that 2 1

2⁄ miles of such wire line could put up in an hour.
Page 60

ordered to Cairo, Illinois, to await orders for a new

assignment. Very soon thereafter he was either designated (or he may have himself decided) to prepare a field manual on signaling, and there soon

appeared, with a prefatory note dated January

1864, a pamphlet of 148 pages, a copy of which is

now in the Rare Book Room of the Library of

Congress. The title page reads as follows:

A Manual of Signals: for the use of signal officers in the field. By Col. Albert J. Myer, Signal

Officer of the Army, Washington, D.C., 1864.

Even in this first edition, printed on an Army

press, Myer devoted nine pages to a reprint of an

article from Harper’s Weekly entitled “Curiosities

of Cipher,” and in the second edition, 1866, he

expanded the section on cryptography to sixty

pages. More editions followed, and I think we may

well say that Myer’s Manual, in its several editions,

was the pioneer American text on military signaling. But I’m sorry to say that as regards cryptology

it was rather a poor thing. Poe had done better

twenty years before that in his essay entitled “A few

words on secret writing.” 

Because of its historic nature, you may like to

see what Myer’s original “wig-wag code” was like. It

was called a “two element code” because it

employed only two digits, 1 and 2, in permutations

of 1, 2, 3 and 4 groups. For example, A was represented by the permutation 22; B by 2122; and C, by

121, etc. In flag signaling, a “1” was indicated by a

motion to the left, and a “2” by a motion to the right.

Later these motions were reversed, for reasons that

must have been good then but are now not obvious.2 Myer’s two-element code, which continued to

be used until 1912, is shown in the figure below.

We must turn our attention now to the situation

as regards the organization for signaling in the

Confederate Army. It is of considerable interest to

A – 22 M – 1221 Y – 111

B – 2122 N – 11 Z – 2222

C – 121 O – 21 & – 1111

D – 222 P – 1212 ing – 2212

E – 12 Q – 1211 tion – 1112

F – 2221 R – 211

G – 2211 S – 212 End of word -3

H – 122 T – 2 End of sentence -33

I – 1 U – 112 End of message -333

J – 1122 V – 1222 Affirmative -22.22.22.3

K – 2121 W – 1121 Repeat -121.121.121

L – 221 X – 2122 Error -212121

Note: No. 3 (end of word) was made by a forward downward motion, called 

“front.” There were about a dozen more signals, for numerals, for frequently 

used short sentences, etc.
Page 61

note that in the first great engagement of the war,

the first Bull Run battle, the Confederate signal officer was that young lieutenant, E.P. Alexander, who

had assisted in demonstrating the wig-wag system

before a board appointed by the War Department

to study Myer’s system. Alexander, now a captain in

grey, used Myer’s system during the battle, which

ended in disaster for the Union forces; it is said that

Alexander’s contribution by effective signaling was

an important factor in the Confederate victory. Dr.

Thompson, whom I have quoted before, says of this

battle:

Thus the fortunes of war in this battle saw

Myer’s system of signals succeed, ironically, on the side hostile to Myer. Because of

general unpreparedness and also some

disinterest and ignorance, the North has

neither wig-wag nor balloon observations.

The only communication system that succeeded

in signal work for the Union army was the infant

USMTC. But the Confederate system under

Alexander, off to a good start at Bull Run, throughout the war operated with both visual and electric

telegraphy, and the Confederates thought highly

enough of their signal service to establish it on 

an official basis on 19 April 1862, less than a year

after that battle. Thus, although the Confederate

Signal Corps never became a distinct and independent branch of the Army as did the Union

Signal Corps, it received much earlier recognition

from the Confederate government than did the

Signal Corps of the federal government. Again

quoting Dr. Thompson:

The Confederate Signal Corps was thus

established nearly a year earlier than its

Federal counterpart. It was nearly as

large, numbering some 1,500, most of the

number, however, serving on detail. The

Confederate Signal Corps used Myer’s system of flags and torches. The men were

trained in wire telegraph, too, and

impressed wire facilities as needed. But

there was nothing in Richmond or in the

field comparable to the extensive and

tightly controlled civilian military telegraph organization which Secretary

Stanton ruled with an iron hand from

Washington.

We come now to the codes and ciphers used by

both sides in the war, and in doing so we must consider that on the Union side, there were, as I have

indicated, two separate organizations for signal

communications, one for visual signaling, the other

for electric. We should therefore not be too astonished to find that the cryptosystems used by the 

two competing organizations were different. On 

the other hand, on the Confederate side, as just

noted, there was only one organization for signal

communications, the Signal Corps of the

Confederate States Army, that used both visual and

electric telegraphy, the latter facilities being 

taken over and employed when and where they

were available. There were reasons for this marked

difference between the way in which the Union

and the Confederate signal operations were organized and administered, but I do not wish to go into

them now. One reason, strange to say, had to do

with the difference between the cryptocommunication arrangements in the Union and the

Confederate armies.

We will discuss the cryptosystems used by both

the Federal Signal Corps first and then those of the

Confederate Signal Corps. Since both corps used

visual signals as their primary means, we find them

employing Myer’s visual-signaling code shown

above. At first both sides sent unenciphered messages; but soon after learning that their signals

were being intercepted and read by the enemy, each

side decided to do something to protect its messages. Initially both decided on the same artifice,

viz, changing the visual signaling equivalents for

the letters of the alphabet, so that, for instance, “22”

was not always “A,” etc. This sort of changing-about

of values soon became impractical, since it prevented memorizing the wig-wag equivalents once and

for all. The difficulty in the Union army’s Signal

Corps was solved by the introduction into usage of 
Page 62

Fig. 55
Page 63

a cipher disk invented by Myer himself. A full

description of the disk in its various embodiments

will be found in Myer’s Manual, but here’s a picture

of three forms of it. You can see how readily the

visual wig-wag equivalents for letters, figures, etc.,

can be changed according to some prearranged

indicator for juxtaposing concentric disks. In my

figure 55, the top left disks (fig. 1 of Myer’s Plate

XXVI) show that the letter A is represented by 112,

B by 22, etc. By moving the two circles to a different

juxtaposition, a new set of equivalents will be established. Of course, if the setting is kept fixed for a

whole message, the encipherment is strictly

monoalphabetic; but Myer recommends changing

the setting in the middle of the message or, more

specifically, at the end of each word, thus producing

a sort of polyalphabetic cipher that would delay

solution a bit. An alternative way, Myer states,

would be to use what he called a “countersign

word,” but that we call a key word, each letter of

which would determine the setting of the disk or for

a single word or for two consecutive words, etc.

Myer apparently did not realize that retaining or

showing externally, that is, in the cipher text, the

lengths of the words of the plain text very seriously

impairs the security of the cipher message. A bit

later we shall discuss the security afforded by the

Myer disk in actual practice.

In the Confederate Signal Corps, the system

used for encipherment of visual signals was apparently the same as that used for enciphering telegraphic messages, and we shall soon see what it

was. Although Myer’s cipher disk was captured a

number of times, it was apparently disdained by the

Confederates, who preferred to use a wholly different type of device, as will be described presently, for

both visual and electric telegraphy.

So much for the cryptosystems used in connection with visual signals by the Signal Corps of both

the North and the South, systems that we may designate as “tactical ciphers.” We come now to the

systems used for what we may call “strategic

ciphers,” because the latter were usually exchanged

between the seat of government and field commanders, or among the latter. In the case of these

communications, the cryptosystems employed by

each side were quite different.

On the Northern side, the USMTC used a system based upon what we now call transposition,

but in contemporary accounts they were called

“route ciphers,” and that name has stuck. The designation isn’t too bad, because the processes of

encipherment and decipherment, though dealing

not with the individual letters of the message but

with entire words, involves following the prescribed

routes in a diagram in which the message is written.

I know no simpler or more succinct description of

the route cipher than that given by one of the

USMTC operators, J.E. O’Brien, in an article in

Century Magazine, XXXVIII, September 1889,

entitled “Telegraphing in Battle”:

The principle of the cipher consisted in

writing a message with an equal number of

words in each line, then copying the words

up and down the columns by various

routes, throwing in an extra word at the

end of each column, and substituting other

words for important names and verbs.

A more detailed description in modern technical terms would be as follows: a system in which in

encipherment the words of the plaintext message

are inscribed within a matrix of a specified number

of tows and columns, inscribing the words within

the matrix from left. to right, in successive lines and

rows downward as in ordinary writing, and taking

the words out of the matrix, that is, transcribing

them, according to a prearranged route to form the

cipher message. The specific routes to be followed

were set forth in numbered booklets, each being

labeled “War Department Cipher” followed by a

number. In referring to them hereinafter, I shall use

the terms “cipher books” or, sometimes more simply, the term “ciphers,” although the cryptosystem

involves both cipher and code processes. It is true

that the basic principle of the system, that of transposition, makes the system technically a cipher system as defined in our modern terminology; but the
Page 64

use of “arbitraries,” as they were called, that is,

words arbitrarily assigned to represent the names

of persons, geographic points, important nouns,

and verbs, etc., makes the system technically a code

system as defined in our modern terminology.

There were in all about a dozen cipher books

used by the USMTC throughout the war. For the

most part they were employed consecutively, but it

seems that sometimes two different ones were

employed concurrently. They contained not only

the specific routes to be used but also indicators for

the routes and for the sizes of the matrices; and, of

course, there were lists of code words, with their

meanings. These route ciphers were supposed to

have been the invention of Anson Stager, whom I

have mentioned before in connection with the

establishment of the USMTC, and who is said to

have first devised such ciphers for General

McClellan’s use in West Virginia in the summer of

1861, before McClellan came to Washington to

assume command of the Army of the Potomac.

Anson Stager and many others thought that he

was the original inventor of the system, but such a

belief was quite in error because word-transposition methods similar to Stager’s were in use hundreds of years before his time. For instance, in

1685, in an unsuccessful attempt to invade

Scotland, in a conspiracy to set the Duke of

Monmouth on the throne, Archibald Campbell, 9th

Earl of Argyll, suffered an unfortunate “accident”:

he was taken prisoner and beheaded by order of

James the Second. The communications of the poor

Earl were not secure, and when they fell into government hands they were soon deciphered. The

method Argyll used was that of word transposition,

and if you are interested in reading a contemporary

account of how it was solved, look on pages 56-59 of

that little book I mentioned before as being one of

the very first books in English dealing with the subject of cryptology, that by James Falconer, entitled

Cryptomenysis Patefacta: Or the Art of Secret

Information Disclosed Without a Key, published in

London in 1685. There you will find the progenitor

of the route ciphers employed by the USMTC, 180

years after Argyll’s abortive rebellion.

The route ciphers employed by the USMTC are

fully described in a book entitled The Military

Telegraph during the Civil War, by Colonel

William R. Plum, published in Chicago in 1882. I

think Plum’s description of them is of considerable

interest, and I recommend his book to those of you

who may wish to learn more about them, but they

are pretty much all alike. If I show you one example

of an actual message and explain its encipherment

and decipherment, I will have covered practically

the entire gamut of the route ciphers used by the

USMTC, so basically very simple and uniform were

they. And yet, believe it or not, legend has it that the

Southern signalmen were unable to solve any of the

messages transmitted by the USMTC. This longheld legend I find hard to believe. In all the descriptions I have encountered in the literature, not one

of them, save the one quoted above from O’Brien,

tries to make these ciphers as simple as they really

were; somehow, it seems to me, a subconscious

realization on the part of Northern writers, usually

ex-USMTC operators, of the system’s simplicity

prevented a presentation that would clearly show

how utterly devoid it was of the degree of sophistication one would be warranted in expecting in the

secret communications of a great modern army in

the decade 1860-1870, three hundred years after

the birth of modern cryptography in the papal

states of Italy.

Let us take the plain text of a message that Plum

(p. 58) used in an example of the procedure in encipherment. The cipher book involved is No.4, and I

happen to have a copy of it so we can easily check

Plum’s work. Here’s the message to be enciphered:

Washington, D.C.

July 15, 1863

For Simon Cameron

I would give much to be relieved of the

impression that Meade, Couch, Smith and
Page 65

all, since the battle of Gettysburg, have

striven only to get the enemy over the river

without another fight. Please tell me if you

know who was the one corps commander

who was for fighting, in the council of war

on Sunday night.

(Signed) A. Lincoln

Plum shows the word-for-word encipherment

in a matrix of seven columns and eleven rows.3

He fails to tell us why a matrix of those dimensions

was selected; presumably the selection was made 

at random, which was certainly permissible. (See

fig. 56.)

Note the seven “nulls” (nonsignificant, or

“blind” words) at the tops and bottoms of certain

columns, these being added to the cipher text in

order to confuse a would-be decipherer. At least

that was the theory, but how effective this subterfuge was can be surmised, once it became known

that employing nulls was the usual practice. Note

also the two nulls (bless and him) at the end of the

last line to complete that line of the matrix. Words

in italics are “arbitraries” or code words.

The cipher message is then copied down following the route prescribed by the indicator

“BLONDE,” as given on page 7 of Cipher Book No.4

for a message of eleven lines. The indicator could

have also been “LINIMENT .”

To explain the diagram at the top of figure 57, I

will show you the “Directions for Use” that appear

on the reverse side of the title page of “War

Department Cipher No.4,” because I’m afraid you

wouldn’t believe me if I merely told you what they

Fig. 56
say. In figure 58 is a picture of the title page, and I

follow it with figure 59, a photograph of what’s on

its reverse.

Do you imagine that the chap who was responsible for getting this cipher book approved ever

thought about what he was doing when he caused

those “Directions for Use” to be printed? It doesn’t

seem possible. All he would have had to ask himself

was, “Why put this piece of information in the book

itself? Cipher books before this have been captured.

Suppose this one falls into enemy hands; can’t he

read, too, and at once learn about the intended

deception? Why go to all the trouble of including

“phony” routes, anyway? If the book doesn’t fall

into enemy hands, what good are the “phony”

routes anyway? Why not just indicate the routes in

a straightforward manner, as had been done

before? Thus: “Up the 6th column (since “6” is the

first number at the left of the diagram), down the

3rd, up the 5th, down the 7th. up the 1st, down the

4th, and down the 2nd.” This matter is so incredibly fatuous that it is hard to understand how sensible men – and they were sensible – could be so

illogical in their thinking processes. But there the

“Directions for Use” stand for all the world to see

and to judge.

Now for the transposition step. The indicator

“BI.ONDE” signifies a matrix of seven columns and

eleven rows, with the route set forth above, viz, up

the 6th column, down the 3rd, etc., so that the

cipher text with a “phony” address and signature,4

becomes as follows:

Washington, D.C

TO: A. HARPER CALDWELL,

Cipher Operator, Army of the Potomac:

Blonde bless of who no optic to get and

impression I Madison square Brown cammer Toby ax the have turnip me Harry

bitch rustle silk Adrian counsel locust you

another only of children serenade flea

Knox County for wood that awl ties get

hound who was war him suicide on for was

please village large bat Bunyan give sigh

incubus heavy Norris on trammeled cat

knit striven without if Madrid quail

upright martyr Stewart man much bear

since ass skeleton tell the oppressing Tyler

monkey.

Page 66

Fig. 57

Fig. 58

Fig. 59
Page 67

(Signed) D. HOMER BATES

Note that the text begins with the indicator

“BLONDE.” In decipherment the steps are simply

reversed. The indicator tells which size matrix to

outline; the words beginning “bless of who no optic.

. .” are inscribed within the matrix: up the 6th column; then omitting the “check word” or “null”

(which in this case is the word “square”) down the

3rd column, etc. The final result should correspond

to what is shown in figure 56. There then follows

the step of interpreting orthographic deviations,

such as interpreting “sigh,” “man,” “cammer ,” and

“on” as Simon Cameron; the word “wood” for

“would,” etc. The final step reproduces the original

plain text.

Save for one exception, all the route ciphers

used by the USMTC conformed to this basic pattern. The things that changed from one cipher book

to the next were the indicators for the dimensions

of the matrices and for the routes, and the “arbitraries” or code equivalents for the various items

comprising the “vocabulary,” the number of them

increasing from one edition to the next, just as

might be expected. The sole exception to this basic

pattern is to be seen in Cipher Book No, 9 and on

only one page of the book. I will show you that page.

(See fig. 60.)

What we have here is a deviation from the

straightforward route transposition, “up the column, . . .down the. . . column,” etc. By introducing

one diagonal path in the route (the 6th, 7th, 8th,

9th, 10th words in a message of five columns, and

the 1st, 2nd, 3rd, 4th, 5th, and 6th words in a message of six columns) the simple up and down route

no longer holds true. The words on the diagonal

interrupt the normal up and down paths and introduce complexities in the method. In fact, the complexities seemed to be a bit too much for the

USMTC cipher operators, because, as far as available records show, these complicated routes were

never used.

I now wish to make a number of general and a

few specific comments on Plum’s description of the

cryptosystems used by the USMTC.

First, we have learned that although Anson

Stager has been credited with inventing the type of

cipher under consideration in this study, he was

anticipated in the invention by about 200 years.

Also, he is given the lion’s share of the credit for

devising those ciphers, although he did have a number of collaborators. Plum names four of them, presumably because he thought them worthy of being

singled out for particular attention. Plum and others tell us that copies of messages handled by the

USMTC were sometimes intercepted by the enemy

but not solved. He cites no authority for this last

statement, merely saying that such intercepts were

published in the newspapers of the Confederacy

with the hope that somebody would come up with

their solution. And it may be noted that none of the

Confederate accounts of war activities cite

instances of the solution of intercepted USMTC

messages, although there are plenty of citations of

instances of interception and solution of enciphered visual transmissions of the Federal army’s

signal corps.

Plum states that twelve different cipher books

were employed by the Telegraph Corps, but I think

there were actually only eleven. The first one was

not numbered, and this is good evidence that a long

war was not expected. This first cipher book had

sixteen printed pages. But for some reason, now

impossible to fathom, the sequence of numbered

books thereafter was as follows: Nos. 6 and 7, which

were much like the first (unnumbered) one; then

came Nos. 12, 9, 10 – in that strange order; then

came Nos. 1 and 2; finally came Nos. 3, 4, and 5.

(Apparently there was no No.8 or No. 11 – at least

they are never mentioned.) It would be ridiculous

to think that the irregularity in numbering the successive books was for the purpose of communication security, but there are other things about the

books and the cryptosystem that appear equally

silly. There may have been good reasons for the

erratic numbering of the books, but if so, what they
Page 68

were is now unknown. Plum states that No.4, the

last one used in the war, was placed into effect on

23 March 1865, and that it and all other ciphers

were discarded on 20 June 1865. However, as

noted, there was a No.5, which Plum says was given

a limited distribution. I have a copy of it, but

whether it was actually put into use I do not know.

Like No.4, it had forty pages. About twenty copies

were sent to certain members of the USMTC, scattered among twelve states; and, of course,

Washington must have had at least one copy.

We may assume with a fair amount of certainty

that the first (the unnumbered) cipher book used by

the USMTC was merely an elaboration of the one

Stager produced for the communications of the

governors of Ohio, Indiana, and Illinois, and of

which a copy is given by only one of the writers who

have told us about these ciphers, namely, David H.

Bates. Bates, in his series of articles entitled

“Lincoln in the Telegraph Office” (The Century

Magazine, Vol. LXXIV, Nos 1-5, May-September,

1907)5 shows a facsimile thereof (p. 292, June 1907

issue), and I have had as good a reproduction made

of it as possible from rather poor photographic facsimile. The foregoing cipher is the prototype upon

which all subsequent cipher books were based, the

first of the War Department series being the one

shown by Plum.

Fig. 60
Page 69

When these ciphers came into use, it was not

the practice to misspell certain words intentionally;

but as the members of the USMTC (who, as I’ve told

you, served not only as telegraph operators but also

as cipher clerks) developed expertness, the practice

of using nonstandard orthography was frequently

employed to make solution of messages more difficult. You have already seen examples of this practice, and one can find hundreds of other examples

of this sort of artifice. Then, further to increase

security, more and more code equivalents were

added to represent such things as ordinal and cardinal numbers, months of the year, days of the

week, hours of the day, punctuation, etc. As a last

step, additional code equivalents for frequently

used words and phrases were introduced. One good

example of two typical pages from one of these

books will characterize them all. 

You will notice that the code equivalents are

printed, but their meanings are written in by hand.

This was usually the case, and the reason is obvious: for economy in printing costs, because the

printed code equivalents of plaintext items in

cipher books belonging to the same series are identical; only their meanings change from one book to

another; and, of course, the transposition routes,

their indicators, and other variables change from

one book to another. I am fortunate in having six of

these cipher books in my private collection, so that

comparisons among them are readily made. The

first feature to be noted is that the code equivalents

are all good English dictionary words (or proper

nouns) of not less than three nor more than seven

(rarely eight) letters. A careful scrutiny shows that

in the early editions the code equivalents are such

as not very likely to appear as words in the plaintext

messages; but in the later editions, beginning with

No. 12, more than 50 percent of the words used as

code equivalents are such as might well appear in

the plain text of messages. For example, words

such as AID, ALL, ARMY, ARTILLERY, JUNCTION, CONFEDERATE, etc., baptismal names of

persons, and names of cities, rivers, bays, etc.,

appear as code equivalents. Among names used as

code equivalents are SHERMAN, LINCOLN,

THOMAS, STANTON, and those of many other

prominent officers and officials of the Union army

and the federal government, as well as of the

Confederate army and government; and, even more

intriguing, such names were employed as indicators for the number of columns and the routes used

– the so-called “Commencement Words.” It would

seem that names and words such as those I’ve menFig. 61.
Page 70

tioned might occasionally have brought about

instances where difficulty in deciphering messages

arose from this source of confusion, but the literature doesn’t mention them. I think you already realize why such commonly used proper names and

words were not excluded. There was, indeed,

method in this madness.

But what is indeed astonishing to note is that in

the later editions of these cipher books, in a great

majority of cases, the words used as “arbitraries”

differ from one another by at least two letters (for

example, LADY and LAMB, LARK and LAWN,

ALBA and ASIA, LOCK and WICK, MILK and

MINT) or by more than two (for example, MYRTLE

and MYSTIC, CARBON and CANCER, ANDES and

ATLAS). One has to search for cases in which two

words differ by only one letter, but they can be

found if you search long enough for them, for example, QUINCY and QUINCE, PINE and PIKE, NOSE

and ROSE. Often there are words with the same initial trigraph or tetragraph, but then the rest of the

letters are such that errors of transmission or

reception would easily manifest themselves, for

example, in the cases of MONSTER and

MONARCH, MAGNET and MAGNOLIA. All in all,

it is important to note that the compiler or compilers of these cipher books had adopted a principle

known today as the “two-letter differential,” a feature found only in codebooks of a much later date.

In brief, the principle involves the use, in a given

codebook, of code groups differing from one another by at least two letters. This principle is employed

by knowledgeable code compilers to this very day,

because it enables the recipient of a message not

only to detect errors in transmission or reception,

but also to correct them. This is made possible if the

permutation tables used in constructing the codewords are printed in the codebooks, so that most

errors can be corrected without calling for a repetition of the transmission. It is clear, therefore, that

the compilers of these cipher books took into consideration the fact that errors are to be expected in

Morse telegraphy, and by incorporating, but only to

a limited extent, the principle of the two-letter differential, they tried to guard against the possibility

that errors might go undetected. Had artificial fiveletter groups been used as code equivalents, instead

of dictionary words, possibly the cipher books

would also have contained the permutation tables.

But it must be noted that permutation tables made

their first appearance only about a quarter of a century after the Civil War had ended, and then only in

the most advanced types of commercial codes.

There is, however, another feature about the

words the compilers of these books chose as code

equivalents. It is a feature that manifests real perspicacity on their part, and you probably already

have divined it. A few moments ago I said that I

would explain why, in the later and improved editions of these books, words that might well be

words in plaintext messages were not excluded

from the lists of code equivalents: it involves the

fact that the basic nature of the cryptosystem in

which these code equivalents were to be used was

clearly recognized by those who compiled the

books. Since the cryptosystem was based upon

word transposition, what could be more confusing

to a would-be cryptanalyst working with messages

in such a system than to find himself unable to

decide whether a word in the cipher text of a message he is trying to solve is actually in the original

plaintext message and has its normal meaning, or is

a codeword with a secret significance – or even a

null, a nonsignificant word, a “blind” or a “check

word,” as those elements were called in those days?

That, no doubt, is why there are, in these books, so

many code equivalents that might well be “good”

words in the plaintext message. And in this connection I have already noted an additional interesting

feature: at the top of each page devoted to indicators for signaling the number of columns or rows in

the specific matrix for a message are printed the socalled “commencement words,” or what we now

call “indicators.” Now there are nine such words, in

sets of three, anyone of which could actually be a

real word or name in the plaintext message. Such

words when used as indicators could be very confusing to enemy cryptanalysts, especially after the

transposition operation. Here, for example, are the

“commencement words” on page 5 of cipher book
No.9: Army, Anson, Action, Astor, Advance,

Artillery, Anderson, Ambush, Agree; on page 7 of

No. 10: Cairo, Curtin, Cavalry, Congress, Childs,

Calhoun, Church, Cobb, etc. Moreover, in Nos. 1, 3,

4, 5, and 10 the “line indicators,” that is, the words

indicating the number of horizontal rows in the

matrix, are also words that could easily be words in

the plaintext messages. For example, in No.1, page

3, the line indicators are as follows:

Note two things in the foregoing list first, there

are variants – there are two indicators for each

case; and, second, the indicators are not in strict

alphabetic sequence. This departure from strict

alphabeticity is even more obvious in the pages

devoted to vocabulary, a fact of much importance

cryptanalytically. Note this feature, for example, in

figure 62, that shows pages 14 and 15 of cipher book

No. 12.

In this respect, therefore, these books partake

somewhat of the nature of two-part or “randomized” codes or, in British terminology, “hatted”

codes. In the second lecture of this series, the physical difference between one-part and two-part

codes was briefly explained, but an indication of the

technical cryptanalytic difference between these

two types of codes may be useful at this point. Twopart codes are much more difficult to solve than

one-part codes, in which both the plaintext elements and their code equivalents progress in parallel sequences. In the latter type, determination of

the meaning of one code group quickly and rather

easily leads to the determination of the meanings of

other code groups above or below the one that has

been solved. For example, in the following short but

illustrative example, if the meaning of code group

1729 has been determined to be “then,” the meanAddress 1 Faith Assume 6 Bend

Adjust 2 Favor Awake 7 Avail

Answer 3 Confine Encamp 8 Active

Appear 4 Bed Enroll 9 Absent

Fig. 62

Page 71
Page 72

ing of the code group 1728 could well be “the” and

that of the code group 1730, “there.”

But in a two-part code, determining the meaning of the code group 0972 to be “then” gives no

clue whatsoever to the meaning of the groups 7621

or 1548. For ease in decoding messages in such a

code, there must be a section in which the code

groups are listed in numerical sequence and are

accompanied by their meanings, which, of course,

will be in a random sequence. The compilers of the

USMTC code books must have had a very clear idea

of what I have just explained, but they made a compromise of a practical nature between a strictly onepart and a strictly two-part code, because they realized that a code of latter sort is twice as bulky as one

of the former sort, besides being much more the

laborious to compile and check the contents for

accuracy. The arrangement they chose wasn’t too

bad, so far as cryptosecurity was concerned. As a

matter of fact, and speaking from personal experience, in decoding a rather long message addressed

to General Grant, I had a difficult time in locating

many of the code words in the book, because of the

departure from strict alphabeticity. I came across

that message in a workbook in my collection, the

workbook of one of the important members of the

USMTC – none other than our friend Plum, from

whose book The Military Telegraph during the

Civil War comes much of the data I’ve presented in

this lecture. On the flyleaf of Plum’s workbook

appears, presumably in his own handwriting, the

legend “W.R. Plum Chf Opr with Gen. G.H.

Thomas.” Here’s one of the messages (fig. 63) he

enciphered in cipher book No.1, the book in which,

he says, more important telegrams were sent than

in any other: Note how many “arbitraries” appear

in the plaintext message, that is, before transposition. After transposition, the melange of plain text,

codewords, indicators and nulls makes the cryptogram mystifying.6 And yet, was the system as

inscrutable as its users apparently thought? It is to

be remembered, of course, that messages were then

transmitted by wire telegraphy, not by radio, so that

enemy messages could be obtained only by “tapping” telegraph lines or capturing couriers or headquarters with their files intact. Opportunities for

these methods of acquiring enemy traffic were not

frequent, but they did occur from time to time, and

in one case a Confederate signalman hid in a

swamp for several weeks and tapped a federal telegraph line, obtaining a good many messages. What

success, if any, did Confederate cryptanalysts have

in their attempts to solve such USMTC cryptograms

as they did intercept? We shall try to answer this

question in due time.

As indicated earlier, there were no competing

signal organizations in the Confederacy as there

were on the Union side. There was nothing at the

center of government in Richmond or in the com1728 – the 7621 – the

1729 – then 0972 – then

1730 – there 1548 – there

Fig. 63
Page 73

bat zone comparable to the extensive and tightly

controlled civilian military telegraph organization

that Secretary Stanton ruled with such an iron hand

from Washington. Almost as a concomitant, it

would seem, there was in the Confederacy, save for

two exceptional cases, one and only one officially

established cryptosystem to serve the need for protecting tactical as well as strategic communications,

and that was the so-called Vigenère Cipher, which

apparently was the cipher authorized in an official

manual prepared by Captain J .H. Alexander as the

partial equivalent of Myer’s Manual of Signals. You

won’t find the name Vigenère in any of the writings

of contemporary signal officers of either the North

or the South. The signalmen of those days called it

the “Court Cipher,” this term referring to the system in common use for diplomatic or “court” secret

communications about this period in history. It is

that cipher that employs the so-called Vigenère

Square with a repeating key. 7 In figure 64 is the

square that Plum calls the “Confederate States

Cipher Key” and that is followed by his description

of its manner of employment. 

There are certain comments to be made on the

two sample messages given by Plum. In the first

place, in one of the messages certain words are left

unenciphered; in the second place, in both sample

messages, the ciphers retain and clearly show the

lengths of the words that have been enciphered.

Both of these faulty practices greatly weaken the

security of ciphers because they leave good clues to

their contents and can easily result in facilitating

solution of the messages. We know today that

cipher messages must leave nothing in the clear.

Even the address and the signature, the date, time

and place of origin, etc., should if possible be hidden; and the cipher text should be in completely

regular groupings, first, so as not to disclose the

lengths of plaintext words, and, second, to promote

accuracy in transmission and reception.

So far as my studies have gone, I have not found

a single example of a Confederate Vigenére cipher

that shows neither of these two fatal weaknesses.

The second of the two examples is the only case I

have found in which there are no unenciphered

words in the text of the message. And the only

example I have been able to find in which word

lengths are not shown (save for one word) is in the

case of the following message:

Vicksburg, Dec. 26,1862.

GEN J.E.JOHNSTON,JACKSON:

I prefer oaavvr, it has reference to

xhvkjqchffabpzelreqpzwnyk to prevent

anuzeyxswstpjw at that point, raeelpsghvelvtzfautlilaslt lhifnaigtsmmlfgccajd.

(Signed) J .C. PEMBERTON

Lt. Gen, Comdg.

Even in this case there are unenciphered words

that afforded a clue enabling our man Plum to find

the key and solve the message. It took some time,

however, and the story is worth telling.

According to Plum, the foregoing cipher message was the very first one captured by USMTC

operators, and it was obtained during the siege of

Vicksburg, which surrendered on 4 July 1863. But

note the date of the message: 26 December 1862.

What was done with the captured message during

the months from the end of December 1862 to July

1863? Apparently nothing. Here is what Plum

reports:

What efforts General Grant caused to be

made to unravel this message, we know

not. It was not until October, 1864, that it

and others came into the hands of the telegraph cipherers, at New Orleans, for translation. . . .

The New Orleans operators who worked

out this key (Manchester Bluff) were aided

by the Pemberton cipher and the original

telegram, which was found among the general’s papers, after the surrender of

Vicksburg; also by the following cipher dispatch, and one other.
Page 74

Plum gives the messages involved, their solution, and the keys, the latter being the three cited

above. It would seem that if the captured

Pemberton message had been brought to General

Grant’s attention and he did nothing about it, he

was not much interested in intelligence. Second,

the solution of the Pemberton message and the others apparently took some time, even though there

was one message with its plain text (the Pemberton

message) and two messages not only with interspersed plaintext words but also with spaces showing word lengths. But Plum does not indicate how

long it took for solution. Note that he merely says

that the messages came into the hands of the telegraph cipherers in October 1864; he does not tell

when solution was reached. 

In the various accounts of these Confederate

ciphers, there is one and only one writer who makes

a detailed comment on the two fatal practices to

which I refer. A certain Dr. Charles E. Taylor, a

Confederate veteran (in an article entitled “The

Signal and Secret Service of the Confederate

States,” published in the Confederate Veteran, Vol.

XL, August-September 1932), after giving an example of encipherment according to the “court

cipher,” says:

It hardly needs to be said that the division

between the words of the original message

as given above was not retained in the

cipher. Either the letters were run together continuously or breaks, as if for words,

were made at random. Until the folly of the

method was revealed by experience, only a

few special words in a message were put

into cipher, while the rest was sent in plain

language. Thus... I think it may be said that

it was impossible for well prepared cipher

to be correctly read by anyone who did not

know the key-word. Sometimes, in fact, we

could not decipher our own messages

Fig. 64
Page 75

when they came over telegraph wires. As

the operators had no meaning to guide

them; letters easily became changed and

portions, at least, of messages rendered

unmeaningly [sic] thereby.

Frankly, I don’t believe Dr. Taylor’s comments

are to be taken as characterizing the practices that

were usually followed. No other ex-signalman who

has written about the ciphers used by the

Confederate Signal Corps makes such observations,

and I think we must simply discount what Dr.

Taylor says in this regard.

It would certainly be an unwarranted exaggeration to say that the two weaknesses in the

Confederate cryptosystem cost the Confederacy the

victory for which it fought so mightily, but I do feel

warranted at this moment in saying that further

research may well show that certain battles and

campaigns were lost because of insecure cryptocommunications.

A few moments ago I said that, save for an

exception or two, there was in the Confederacy one

and only one cryptosystem to serve the need for

secure tactical as well as strategic communications.

One of these exceptions concerned the cipher used

by General Beauregard after the battle of Shiloh (8

April 1862). This cipher was purely monoalphabetic in nature and was discarded as soon as the official cipher system was prescribed in Alexander’s

manual. It is interesting to note that this was done

after the deciphered message came to the attention

of Confederate authorities in Richmond via a

Northern newspaper. It is also interesting to note

that the Federal War Department had begun using

the route cipher as the official system for USMTC

messages very promptly after the outbreak of war,

whereas not until 1862 did the Confederate States

War Department prepare an official cryptosystem,

and then it adopted the “court cipher.”

The other exception involved a system used at

least once before the official system was adopted,

and it was so different from the latter that it should

be mentioned. On 26 March 1862 the Confederate

States president, Jefferson Davis, sent General

Johnston by special messenger a dictionary with

the following accompanying instruction:8

I send you a dictionary of which I have the

duplicate, so that you may communicate

with me by cipher, telegraphic or written,

as follows: First give the page by its number; second, the column by the letter L, M,

or R, as it may be, in the left-hand, middle,

or right-hand columns; third, the number

of the word in the column, counting from

the top. Thus, the word junction would be

designated 146, L, 20.

The foregoing, as you no doubt have already

realized, is one of the types of cryptosystems used

by both sides during the American Revolutionary

period almost a century before, except that in this

case the dictionary had three columns to the page

instead of two. I haven’t tried to find the dictionary,

but it shouldn’t take long to locate it, since the code

equivalent of the word “junction” was given: 146, L,

20. Moreover, there is extant at least one fairly long

message, with its decode. How many other messages in this system there may be in the National

Archives I don’t know. 

Coming back now to the “court cipher,” you will

probably find it just as hard to believe, as I find it,

that according to all accounts three and only three

keys were used by the Confederates during the

three and a half years of warfare from 1862 to mid1865. It is true that Southern signalmen mention

frequent changes in key, but only the following

three are specifically cited:

1) COMPLETE VICTORY

2) MANCHESTER BLUFF

3) COME RETRIBUTION

It seems that all were used concurrently. There

may have been a fourth key, IN GOD WE TRUST,
Page 76

but I have seen it only once, and that is in a book

explaining the “court cipher.” Note that each of the

three keys listed above consists of exactly fIfteen

letters, but why this length was chosen is not clear.

Had the rule been to make the cipher messages

contain only five-letter groups, the explanation

would be easy: 15 is a multiple of 5, and this would

be of practical value in checking the cryptographic

work. But, as has been clearly stated, disguising

word lengths was apparently not the practice even

if it was prescribed, so that there was no advantage

in choosing keys that contain a multiple of five letters. And, by the way, doesn’t the key COME RETRIBUTION sound rather ominous to you even

these days?

Sooner or later a Confederate signal officer was

bound to come up with a device to simplify enciphering operations, and a gadget devised by a

Captain William N. Barker seemed to meet the

need. In Myer’s Manual there is a picture of one

form of the device, shown here in figure 65. I don’t

think it was necessary to explain how it worked, for

it is almost self-evident. Several of these devices

were captured during the war, one of them being

among the items in the NSA museum (fig. 66). This

device was captured at Mobile in 1865. All it did was

to mechanize, in a rather inefficient manner, the

use of the Vigenère Cipher.

How many of these devices were in existence or

use is unknown, for their construction was an individual matter – apparently it was not an item of

regular issue to members of the corps.

In practically every account of the codes and

ciphers of the Civil War, you will find references to

ciphers used by Confederate secret service agents

engaged in espionage in the North as well as in

Canada. In particular, much attention is given to a

set of letters in cipher, which were intercepted by

the New York City postmaster and which were

involved in a plot to print Confederate currency and

bonds. Much ado was made about the solution of

these ciphers by cipher operators of the USMTC in

Washington and the consequent breaking up of the

plot. But I won’t go into these ciphers for two reasons. First, the alphabets were all of the simple

monoalphabetic type, a total of six altogether being

used. Since they were composed of a different series

of symbols for each alphabet, it was possible to

compose a cipher word by jumping from one series

to another without any external indication of the

shift. However, good eyesight and a bit of patience

were all that was required for solution in this case

because of the inept manner in which the system

was used: whole words, sometimes several successive words, were enciphered by the same alphabet.

But the second reason for my not going into the

story is that my friend and colleague of my NSA

days, Edwin C. Fishel, has done some research

among the records in our National Archives dealing

with this case, and he has found something of great

interest and that I feel bound to leave for him to tell

at some future time, as that is his story, not mine.

So very fragmentary was the amount of cryptologic information known to the general public in

these days that when there was found on John

Wilkes Booth’s body a cipher square that was

Fig. 66

Fig. 65
Page 77

almost identical with the cipher square that had

been mounted on the cipher reel found in

Confederate secretary of state Judah P. Benjamin’s

office in Richmond, the federal authorities in

Washington attempted to prove that this necessarily meant the Confederate leaders were implicated

in the plot to assassinate Lincoln and had been giving Booth instructions in cipher. Figure 67 is a picture of the cipher square found on Booth, and also

in a trunk in his hotel room in Washington.

The following is quoted from Philip Van Doren

Stern’s book entitled Secret Missions of the Civil

War (New York: Rand McNally and Co., 1951, 320):

Everyone in the War Department who was

familiar with cryptography knew that the

Vigenére was the customary Confederate

cipher and that for a Confederate agent

(which Booth is known to have been) to

possess a copy of a variation of it meant no

more than if a telegraph operator was captured with a copy of the Morse Code.

Hundreds – and perhaps thousands – of

people were using the Vigenére. But the

Government was desperately seeking evidence against the Confederate leaders so

they took advantage of the atmosphere of

mystery which has always surrounded

cryptography and used it to confuse the

public and the press. This shabby trick

gained nothing, for the leaders of the

Confederacy eventually had to be let go for

lack of evidence.

To the foregoing I will comment that I doubt

very much whether “everyone in the War

Department who was familiar with cryptography

knew that the Vigenère was the customary

Confederate cipher.” Probably not one of them had

even heard the name Vigenère or had even seen a

copy of the table, except those captured in operations. I doubt whether anyone on either side even

knew that the cipher used by the Confederacy had a

name; or least of all, that a German army reservist

named Kasiski, in a book published in 1863,

showed how the Vigenère cipher could be solved by

a straightforward mathematical method.

I have devoted a good deal more attention to the

methods and means for cryptocommunications in

the Civil War than they deserve, because professional cryptologists of 1961 can hardly be impressed

either by their efficacy from the point of view of

ease and rapidity in the cryptographic processing,

or by the degree of the technical security they

imparted to the messages they were intended to

Fig. 67
Page 78

protect. Not much can be said for the security of the

visual signaling systems used in the combat zone by

the Federal Signal Corps for tactical purposes,

because they were practically all based upon simple

monoalphabetic ciphers or variations thereof, as for

instance, when whole words were enciphered by

the same alphabet. There is plenty of evidence that

Confederate signalmen were more or less regularly

reading and solving those signals. What can be said

about the security of the route ciphers used by the

USMTC for strategic or high command communications in the zone of the interior? It has already

been indicated that, according to accounts by exUSMTC men, such ciphers were beyond the cryptanalytic abilities of Confederate cryptanalysts, but

can we really believe that this was true?

Considering the simplicity of these route ciphers

and the undoubted intellectual capacities of

Confederate officers and soldiers, why should messages in these systems have resisted cryptanalytic

attack? In many cases the general subject matter of

a message and perhaps a number of specific items

of information could be detected by quick inspection of the message. Certainly, if it were not for the

so-called “arbitraries,” the general sense of the message could be found by a few minutes’ work, since

the basic system must have been known through

the capture of cipher books, a fact mentioned several times in the literature. Capture of but one book

(they were all generally alike) would have told

Confederate signalmen exactly how the system

worked, and this would naturally give away the

basic secret of the superseding book. So we must

see that whatever degree of protection these route

ciphers afforded, message security depended

almost entirely upon the number of “arbitraries”

actually used in practice. A review of such messages

as are available shows wide divergences in the use

of “arbitraries.” In any event, the number actually

present in these books must have fallen far short of

the number needed to give the real protection that

a well-constructed code can give. Thus it seems to

me that the application of native intelligence, with

some patience, should have been sufficient to solve

USMTC messages – or so it would be quite logical

to assume. That such an assumption is well warranted is readily demonstrable.

It was, curiously enough, at about this point in

preparing this lecture that Mr. Edwin C. Fishel,

whom I have mentioned before, gave me just the

right material for such a demonstration. In June of

1960, Mr. Fishel had given Mr. Phillip Bridges, who

is also a member of NSA and who knew nothing

about the route ciphers of the USMTC, the following authentic message sent on 1 July 1863 by

General George G. Meade, at Harrisburg,

Pennsylvania, to General Couch at Washington.

(See fig. 68)

It took Mr. Bridges only a few hours, five or six,

to solve the cryptogram, and he handed the following plain text to Mr. Fishel:

Thomas been it-(Nulls)

For Parson. I shall try and get to you by

tomorrow morning a reliable gentleman

and some scouts who are acquainted with

a country you wish to know of, Rebels this

way have all concentrated in direction of

Gettysburg and Chambersburg. I occupy

Carlisle. Signed Optic. Great battle very

soon. tree mush deal- (Nulls)

The foregoing solution is correct, save for one

pardonable error: “Thomas” is not a “null” but an

indicator for the dimensions of the matrix and the

route. “Parson” and “Optic” are codenames, and I

imagine that Mr. Bridges recognized them as such,

but of course, he had no way of interpreting them,

except perhaps by making a careful study of the

events and commanders involved in the impending

action, a study he wasn’t called upon to undertake.

The foregoing message was enciphered by

Cipher Book No. 12, in which the indicator

THOMAS specifies a “Message of 10 lines and 5

columns.” The route was quite simple and straightforward: “Down the 1st (column), up the 3rd; down

the 2nd; up the 5th down the 4th.”
Page 79

It is obvious that in this example the absence of

many “arbitraries” made solution a relatively easy

matter. What Mr. Bridges would have been able to

do with the cryptogram had there been many of

them is problematical. Judging by his worksheets,

it seemed to me that Mr. Bridges did not realize

when he was solving the message that a transposition matrix was involved; and on questioning him

on this point his answer was in the negative. He

realized this only later.

A minor drama in the fortunes of Major General

D.C. Buell, one of the high commanders of the

Federal army, is quietly and tersely outlined in two

cipher telegrams. The first one, sent on 29

September 1862 from Louisville, Kentucky, was in

one of the USMTC cipher books and was externally

addressed to Colonel Anson Stager, head of the

USMTC, but the internal addressee was Major

General H. W. Halleck, “General-in-Chief’ [our

present day “Chief of Staff”]. The message was

externally signed by William H. Drake, Buell’s

cipher operator, but the name of the actual sender,

Buell, was indicated internally. Here’s the telegram.

COLONEL ANSON STAGER, Washington:

Austria await I in over to requiring orders

olden rapture blissful for your instant

command turned and instructions and

rough looking further shall further the

Camden me of ocean September poker

twenty I the to I command obedience

repair orders quickly pretty Indianapolis

your him accordingly my fourth received

1862 wounded nine have twenty turn have

to to to alvord hasty.

WILLIAM H. DRAKE

Rather than give you the plain text of this message, perhaps you would like to work it out for yourselves, for with the information you’ve already

received the solution should not be difficult. The

Fig. 68
Page 80

message contains one error, which was made in its

original preparation: one word was omitted.

The second telegram, only one day later, was

also from Major General Buell, to Major General

Halleck, but it was in another cipher book – apparently the two books involved were used concurrently. Here it is:

GEORGE C. MAYNARD, Washington:

Regulars ordered of my to public out suspending received 1862 spoiled thirty I dispatch command of continue of best otherwise worst Arabia my command discharge

duty of my last for Lincoln September period your from sense shall duties the until

Seward ability to the I a removal evening

Adam herald tribune.9

PHILIP BRUNER

As before, I will give you the opportunity to

solve this message for yourselves. (At the end of the

next lecture, I shall present the plain text of both

messages.)

Figure 69 is a photograph of an important message that you may wish to solve yourself. It was sent

by President Jefferson Davis to General Johnston,

on a very significant date, 11 April 1865.10 For ease

in working on it, I give also a transcription below,

since the photograph is very old and in a poor state.

I believe that this message does not appear in any of

the accounts I’ve read.

It is time now to tell you what I can about the

success or lack of success that each side had with

the cryptograms of the other side. I wish there were

more information on this interesting subject than

what I am about to present. Most of what sound

information there is comes from a book by a man

named J. Willard Brown, who served four full years

in the Federal army’s signal corps. The book is entitled The Signal Corps, U.S.A., in the War of the

Rebellion, published in Boston in 1896 by the U.S.

Veteran Signal Corps Association. In his book

Brown deals with the cryptanalytic success of both

sides. First, let’s see what the Union signalmen

could do with rebel ciphers. Here are some statements he makes (p. 214):

The first deciphering of a rebel signal code

of which I find any record was that made

by Capt. J.S. Hall and Capt. R.A. Taylor,

reported Nov. 25, 1862. Four days later,

Maj. Myer wrote to Capt. Cushing, Chief

Signal Officer, Army of the Potomac, not to

permit it to become public ‘that we translate the signal messages of the rebel army’.

April 9, 1863, Capt. Fisher, near Falmouth,

reported that one of his officers had read a

rebel message which proved that the

rebels were in possession of our code. The

next day he was informed that the rebel

code taken (from) a rebel signal officer 

Greensboro N.C.

April 11 1865

Benaja 11 Hd Q near H.G.

Genl J.E. Johnston

A scout (reports?) that Genl Lee u i D v v s w

v z F x – m q s – E G A z 0 x – H W – P J M – T z

A T – near to appomattox Court house yesterday No official intelligence of the event D i F – x

Y i k v – q T – F B B H Y G – F A S D – J H i – L

P 0 u B – As to result Gen H. H. Walker is

ordered Y W F T – W S K T M T – B X z S – G q

– X A m E – C H T – i u – A K M S A u P u V F –

Let me hear from you there – I will have need

to see you to confer as to future action. The

above is my telegram of yesterday which is

repeated as requested.

Jeffn Davis

Official

Burton Harrison

Private Secy
Page 81

Fig. 69
Page 82

was identical with one taken previously at

Yorktown.

He received from Maj. Myer the following

orders:

‘Send over your lines, from time to time,

messages which, if it is in the power of the

enemy to decipher them, will lead them to

believe that we cannot get any clew to their

signals

Send also occasionally messages untrue, in

reference to imaginary military movements, as for instance - ‘The Sixth Corps is

ordered to reinforce Keyes at Yorktown’.

Undoubtedly, what we have here are references

to the general cipher system used by the

Confederates in their electric-telegraph communications, for note the expression “Send over your

lines.” This could hardly refer to visual communications. Here we also have very early instances, in 

telegraphic communications, of what we call cover

and deception, i.e., employing certain ruses to try 

to hide the fact that enemy signals could be read,

and to try to deceive him by sending spurious messages for him to read, hoping the fraud will not be

detected.

Brown’s account of Union cryptanalytic successes continues (p. 215):

In October, 1863, Capt. Merril’s party deciphered a code, and in November of the

same year Capt. Thickstun and Capt.

Marston deciphered another in Virginia.

Lieut. Howgate and Lieut. Flook, in March,

1864, deciphered a code in the Western

Army, and at the same time Lieut. Benner

found one at Alexandria, Virginia.

Capt. Paul Babcock, Jr., then Chief Signal

Officer, Department of the Cumberland, in a letter

dated Chattanooga, Tennessee, April 26, 1864,

transmitting a copy of the rebel signal code, says:

Capt Cole and Lieut. Howgate, acting

Signal Officers, occupy a station of communication and observation on White Oak

Ridge at Ringgold, Ga. . . . On the 22nd inst.

the rebels changed their code to the one

enclosed, and on the same day the abovementioned officers by untiring zeal and

energy succeeded in translating the new

code, and these officers have been ever

since reading every message sent over the

rebel lines. Many of these messages have

furnished valuable information to the general commanding the department.

The following is also from Brown (p. 279):

About the first of June (1864), Sergt.

Colvin was stationed at Fort Strong, on

Morris Island, with the several codes

heretofore used by the rebels, for the purpose of reading the enemy signals if possible. For nearly two weeks nothing could be

made out of their signals, but by persevering he finally succeeded in learning their

codes. Messages were read by him from

Beach Inlet, Battery Bee, and Fort

Johnson. Gen. J .G. Foster, who had

assumed command of the Department of

the South, May 26th, was so much pleased

with Sergt. Colvin’s work, that in a letter

addressed to Gen. Halleck, he recommended “that he be rewarded by promotion to Lieutenant in the Signal Corps, or

by a brevet or medal of honor.” This recommendation was subsequently acted

upon, but, through congressional and official wrangling over appointments in the

Corps, he was was not commissioned until

May 13,1865, his commission dating from

Feb 14,1865.

(p. 281):

During the month, Sergt. Colvin added

additional laurels to the fame he had

earned as a successful interpreter of rebel
Page 83

signals. The enemy had adopted a new

cipher for the transmission of important

messages, and the labor of deciphering it

devolved upon the sergeant. Continued

watchfulness at last secured the desired

result, and he was again able to translate

the important dispatches of the enemy for

the benefit of our commandants. The

information thus gained was frequently of

special value in our operations, and the

peculiar ability exhibited by the sergeant

led Gen. Foster once more to recommend

his promotion.

(p. 286):

About the same time an expedition under

Gen. Potter was organized to act in conjunction with the navy in the vicinity of

Bull’s Bay. Lieut. Fisher was with this command, and by maintaining communications between the land and naval forces

facilitated greatly the conjoined action of

the command. Meanwhile every means

was employed to intercept rebel messages.

Sergt. Colvin, assigned to this particular

duty, read all the messages within sight,

and when the evacuation of Charleston

was determined upon by the enemy, the

first notification of the fact I came in this

way before the retreat had actually commenced. As a reward for conspicuous services rendered in this capacity, Capt.

Merrill recommended that the sergeant be

allowed a medal, his zeal, energy and

labors fully warranting the honor.

After the occupation of Charleston, communications was established by signals

with Fort Strong, on Morris Island, Fort

Johnson and James Island, Mount

Pleasant, and Steynmeyer’s Mills. A line

was also opened with the position occupied by the troops on the south side of the

Ashley river.

With regard to Confederate reading of Union

visual signals, Brown makes the following observations of considerable interest (p. 274):

The absolute necessity of using a cipher

when signaling in the presence of the

enemy was demonstrated during these

autumn months by the ease with which the

rebels read our messages. This led to the

issuing of an order that all important messages should be sent in cipher. Among the

multitude of messages intercepted by the

enemy, the following were some of the

more important . . .

Brown thereupon cites twenty-five such messages, but he gives no indication whatever as to the

source from which he obtained these examples or

how he knew they had been intercepted. They all

appear to tactical messages sent by visual signals.

In many of the cases cited by Brown, it is difficult to tell whether wig-wag or electric telegraph

messages were involved. But in one case (evacuation of Charleston), it is perfectly clear that visual

messages were involved, when Brown says that

Sergeant Colvin “read the messages within sight.”

Further with regard to rebel cryptanalytic success with Union messages, Brown has this to say 

(p. 213):

The reports of Lieut. Frank Markoe, Signal

Officer at Charleston, show that during the

siege thousands of messages were sent

from one post to another, and from outposts to headquarters, most of which

could have been sent in no other way, and

many were of great importance to the

Confederate authorities.

Lieut. Markoe says that he read nearly

every message we sent. He was forewarned of our attack on the 18th of July,

1863. He adds, regretfully, however, that

through carelessness of the staff officers at

headquarters it leaked out that he was
Page 84

reading our messages. Our officers then

began to use the cipher disk. In August he

intercepted the following message: “Send

me a copy of rebel code immediately. if you

have one in your possession.” He therefore

changed his code. . .. A little later our officers used a cipher which Lieut. Markoe

says he was utterly unable to unravel.

It is unfortunate that neither Lieutenant

Markoe, the Confederate cryptanalyst, nor Brown,

the Union signalman, tell us what sort of cipher this

was that couldn’t be unraveled. I assume that it was

the Myer disk used properly, with a key phrase of

some length and with successive letters, not whole

words, being enciphered by successive letters of the

key. But this is only an assumption and may be

entirely erroneous.

In the foregoing citations of cryptanalytic success, it is significant to note that visual messages

were intercepted and read by both sides; second,

that Confederate telegraphic messages protected by

the Vigenère cipher were read by Union personnel

whenever such messages were intercepted; and,

third, that USMTC telegraph messages protected by

the route cipher, apparently intercepted occasionally, were never solved. Later I shall make some comments on this last statement, but at the moment let

us note that technically the Vigenère cipher is theoretically much stronger than the route cipher, so

that we have here an interesting situation, viz, the

users of a technically inferior cryptosystem were

able to read enemy messages protected by a technically superior one, but the users of a technically

superior cryptosystem were not able to read enemy

messages protected by a technically inferior one – a

curious situation indeed.

I can hardly close this lecture without citing a

couple of messages that appear in nearly every

account I’ve seen of the codes and ciphers of the

Civil War. These are messages that were sent by

President Lincoln under circumstances in which,

allegedly, the usual cipher could not be, or at least

was not, employed. The first of the two was sent on

25 November 1862 from the White House to Major

General Burnside, Falmouth, Virginia. The circumstances are so bizarre that if I merely presented the

cipher message to you without some background, I

doubt if you would believe me. And even after I’ve

presented the background, I’m sure you won’t know

what to think. I, myself, don’t really know whether

to take the incident seriously or not. Let me quote

from an account of it in the book by David Homer

Bates, one of the first members of the USMTC, in

his Lincoln in the Telegraph Office (New York:

Appleton-Century Co., 1939, 58-61):

During Burnside’s Fredricksburg campaign at the end of 1862, the War

Department operators discovered indications of an interloper on the wire leading

to his headquarters at Aquia Creek. These

indications consisted of an occasional

irregular opening and closing of the circuit

and once in a while strange signals, evidently not made by our own operators. It is

proper to note that the characteristics of

each Morse operator’s sending are just as

pronounced and as easily recognized as

those of ordinary handwriting, so that

when a message is transmitted over a wire,

the identity of the sender may readily be

known to any other operator within hearing who has ever worked with him. A

somewhat similar means of personal identification occurs every day in the use of the

telephone.

At the time referred to, therefore, we were

certain that our wire had been tapped. In

some way or other the Confederate operator learned that we were aware of his presence, and he then informed us that he was

from Lee’s army and had been on our wire

for several days, and that, having learned

all that he wanted to know, he was then

about to cut out and run. We gossiped with

him for a while and then ceased to hear his

signals and believed he was gone.

We had taken measures, however, to discover his whereabouts by sending out line-
Page 85

men to patrol the line; but his tracks were

well concealed, and it was only after the

intruder had left. that we found the place

where our wire had been tapped. He had

made the secret connection by means of

fine silk-covered magnet wire, in such a

manner as to conceal the joint almost

entirely. Meantime, Burnside’s cipheroperator was temporarily absent from his

post, and we had recourse to a crude plan

for concealing the text of telegrams to the

Army of the Potomac, which we had followed on other somewhat similar occasions when we believed the addressee or

operator at the distant point (not provided

with the cipher key) was particularly keen

and alert. This plan consisted primarily of

sending the message backward, the individual words being misspelled and otherwise garbled. We had practiced on one or

two dispatches to Burnside before the

Confederate operator was discovered to be

on the wire, and were pleased to get his

prompt answers, couched also in similar

outlandish language, which was, however,

intelligible to us after a short study of the

text in each case. Burnside and ourselves

soon became quite expert in this homemade cipher game, as we all strove hard to

clothe the dispatches in strange, uncouth

garb.

In order to deceive the Confederate operator, however, we sent to Burnside a number of cipher messages, easy of translation, and which contained all sorts of

bogus information for the purpose of misleading the enemy. Burnside or his operator at once surmised our purpose, and the

general thereupon sent us in reply a lot of

balderdash also calculated to deceive the

uninitiated. It was about this time that the

following specially important dispatch

from Lincoln was filed for transmission:

Executive Mansion, Washington,

November 25,1862. 11:30 AM.

MAJOR-GENERAL BURNSIDE, Falmouth,

Virginia: If I should be in boat off Aquia

Creek at dark tomorrow (Wednesday)

evening, could you, without inconvenience, meet me and pass an hour or two

with me?

A. Lincoln

Although the Confederate operator had

said good-bye several days before, we were

not sure he had actually left. We therefore

put Lincoln’s telegram in our homemade

cipher, so that if the foreign operator were

still on the wire, the message might not be

readily made out by the enemy. I At the

same time extra precautions were taken by

the Washington authorities to guard

against any incident to the President while

on his visit to Burnside. No record is now

found of the actual text of this cipherdespatch, as finally prepared for transmission, but going back over it word for word,

I believe the following is so nearly like it as

to be called a true copy:

Washington, D.C., November 25, 1862

BURNSIDE, Falmouth, Virginia: Can Inn

Ale me withe 2 oar our Ann pass Ann me

flesh ends N. V. Corn Inn out with U cud

Inn heaven day nest Wed roe Moore Tom

darkey hat Greek Why Hawk of Abbott Inn

B chewed I if. BATES

This sort of subterfuge is hardly worthy of

becoming embalmed in the official records of the

war – and apparently it wasn’t. But several years

later, one of identical nature did become so

embalmed, for the message appears on page 236,

Vol. 45, of “Telegrams received by the Secretary of

War”:
Page 86

Hq. Armies of the U.S., City Point, Va.,

8:30 a.m., April 3, 1865

TINKER, War Department: A. Lincoln its

in fume a in hymn to start I army treating

there possible if of cut too forward pushing

is He is so all Richmond aunt confide is

Andy evacuated Petersburg reports Grant

morning this Washington Secretary War.

BECKWITH

Both Plum and Bates cite the foregoing

telegram, and their comments are interesting if not

very illuminating. Plum says merely: “By reading

the above backward with regard to the phonetics

rather than the orthography, the meaning will be

apparent.” Bates says:

The probable reason for adopting this

crude form was to insure its reaching its

destination without attracting the special

attention of watchful operators on the

route of the City Point-Washington wire,

because at that crisis every one was on the

Qui vive for news from Grant’s advancing

army, and if the message had been sent in

plain language, the important information

it conveyed might have been overheard in

its transmission and perhaps would have

reached the general public in advance of

its receipt by the War Department.

It is not necessary to give the translation of

this cipher-message. To use a homely

term, ‘any one can read it with his eyes

shut.’ In fact, the easiest way would be for

one to shut the eyes and let some one else

read it backward, not too slowly. The real

wording then becomes plain.

Can you imagine for one moment that a “cryptogram” of such simplicity could not be read at sight

by any USMTC operator, even without having

someone read it to him backward? Such a “cryptogram” is hardly worthy of a schoolboy’s initial

effort at preparing a secret message. But I assure

you that I did not make this story up, nor did I compose the cryptogram.

Ruminating upon what I have shown and told

you about the cryptosystems used by both sides in

the Civil War, do you get the feeling, as I do, that the

cryptologic achievements of neither side can be said

to add luster to undoubtedly great accomplishments on the battlefield? Perhaps this is a good

place to make an appraisal of the cryptologic efficiency of each side.

First, it is fair to say that we can hardly be

impressed with the cryptosystems used by either

side. The respective signal corps at first transmitted

by visual signals messages wholly in plain language;

such messages were often intercepted and read

straight away. Then both sides began enciphering

such messages, the signal corps of the Federal army

using a cipher disk invented by the Chief Signal

Officer, the signal corps of the Confederate army

using the Vigenère cipher. In both cases the use of

cryptography for tactical messages was quite inept,

although it seems that from time to time the

Federal signalmen had better success with the

Vigenère-enciphered visual messages of the

Confederate signalmen than the latter had with the

disk-enciphered messages of the Union signalmen.

With regard to the cryptosystem used by the

Confederate Signal Corps, although there may initially have been cases in which monoalphabetic

substitution alphabets were used, such alphabets

were probably drawn up by agreement with the signal officers concerned and changed from time to

time. Nowhere have I come across a statement that

the Myer disk or something similar was used. In

any event, messages transmitted by visual signals

were read from time to time by Union signalmen,

the record showing a number of cases in which the

latter “worked out the rebel signal code” – meaning, of course, that the substitution alphabet

involved was solved. When did the Confederate

Signal Corps begin using the Vigenère cipher? The

answer seems to be quite clear. In a letter dated 6

June 1888 from General J .H. Alexander (brother
Page 87

of General E.P.) to J. Willard Brown 11 we find the

following statements:

At the first inauguration of the Signal

Service in the Confederacy, I, having

received in the first place the primary

instruction from my brother, Gen. E.P .A.,

then a colonel on Beauregard’s staff near

the Stone Bridge at Manassas, was

assigned the duty of preparing a confidential circular of instruction for the initiation

of officers and men, in this branch. I did

prepare it, in Richmond, in early spring,

1862, and surrendered the copy to Hon.

James A. Seddon, the then Secretary of

War at Richmond. It was issued in form of

a small pamphlet. I had attached a table

for compiling cipher dispatches – which

was printed with the rest of the matter –

and the whole was issued confidentially

to the officers newly appainted for signal

duty.12

I have italicized the last sentence because I

think that the “table for compiling cipher dispatches” can refer only to the Vigenère square table, for

that and only that sort of table is even mentioned in

accounts of the ciphers used by the Confederacy.

One could, of course, wish the writer had given

some further details, but there are none. However,

the statement about the table is sufficiently explicit

to warrant the belief that it was General J.H.

Alexander who officially introduced the Vigenère

square into Confederate cryptography, although he

may have obtained the idea from his brother, since

he states that “he received in the first place the primary instruction from my brother.”

In the Federal Signal Corps, it is quite possible

that polyalphabetic methods Myer cites in his

Manual for using his cipher disk (changing the setting with successive words of a message) were used

in some cases, because there are found in the record

several instances in which the Confederate signalmen, successful with monoalphabetic encipherments, were completely baffled. One is warranted

in the belief that it was not so much the complexities introduced by using a key word to encipher successive words of the plain text as it was the lack of

training and experience in cryptanalysis that hampered Confederate signalman who tried to solve

such messages. In World War I a German army system of somewhat similar nature was regularly

solved by Allied cryptanalysts, but it must be

remembered, in the first place, that by 1914 the use

of radio made it possible to intercept volumes of

traffic entirely impossible to obtain before the

advent of radiotelegraphy; and in the second place,

would-be cryptanalysts of both sides in the Civil

War had nothing but native wit and intelligence to

guide them in their work on intercepted messages,

for there were, so far as the record goes, no training

courses in cryptanalysis on either side, though

there were courses in cryptography and signaling. It

would seem to cryptanalysts of 1961, a century

later, that native wit and intelligence nevertheless

should have been sufficient to solve practically

every message intercepted by either side, so simple

and inefficient in usage do the cryptosystems

employed by both sides appear today.

No system employed by the Federals, either for

tactical messages (Signal Corps transmissions) or

strategic messages (USMTC transmissions), would

long resist solution today, provided, of course, that

a modicum of traffic was available for study.

Although technically far less secure in actual practice than properly enciphered Vigenère messages,

the route ciphers of the USMTC seem to have eluded the efforts of inexpert Confederate cryptanalysts.

Ex-USMTC operators make the statement that

none of their messages was ever solved, and that

the Confederates published intercepted messages

in Southern newspapers in the hope that somebody

would come forward with a solution; yet it must be

remembered that those operators were

Northerners who were very naturally interested in

making the achievements of the Union operators,

both in cryptography and cryptanalysis, appear

more spectacular than they really were. And it is

probable that they wrote without having made a

real effort to ascertain whether the Confederates
did have any success. A “real effort” would have

been a rather imposing undertaking then – as it still

is, I fear. Now it must be presumed that if

Confederate operators had succeeded in solving

intercepted traffic of the USMTC, they would have

recorded the facts to their own credit. But in his

seven volumes on the campaigns of Lee and his

lieutenants, Douglas S. Freeman does not mention

a single instance of interception and solution of telegraphic messages of the Union. Perhaps Freeman

was seeking 100 percent confirmation, which is too

much to expect in a field of such great secrecy. This

failure of the Confederate cryptanalysts is the more

astonishing when we know that copies of the

USMTC cipher books were captured and that,

therefore, they must have become aware of the

nature of the route ciphers used by the USMTC,

unless there was a lack of appreciation of the value

of such captures and a failure to forward the books

to the proper authorities, who could hand them

over to their experts. In those books the USMTC

route ciphers would have been seen in their naive

simplicity, complicated only by the use of “arbitraries” or code equivalents, but hardly to the

degree where all messages would be impossible to

solve. It seems to me that there can be only four

possible explanations for this failure to solve the

USMTC route ciphers. Let us examine them in turn.

First, it is possible that there was not enough

intercept traffic to permit solution. But this is inadequate as an explanation. The route cipher is of

such simplicity that “depth” is hardly an absolute

requirement – a single message can be solved, and

its intelligibility will be determined to a large degree

by the number of “arbitraries” it contains. When

there are many, only the dim outlines of what is

being conveyed by the message may become visible; where there are few or even none, the meaning

of the messages becomes fairly evident. But the

abundant records, although they contain many references to intercepts, fail to disclose even one

instance of solution of a USMTC message. Thus we

are forced to conclude that it was not the lack of

intercept traffic that accounts for lack of success by

the Confederates with USMTC messages, but some

other factor.

Second, the lack of training in cryptanalysis of

Confederate cryptanalysts might have been the reason why Confederate signalmen failed to solve the

messages. This sounds plausible until we look into

the matter with a critical spirit. Solution of route

ciphers requires little training; native wit and intelligence should have been sufficient. The degree of

intelligence possessed by Confederate officers and

men was certainly as high as that of their Union

counterparts, who were up against a technically far

superior cryptosystem, the Vigenère. We may safely conclude that it was not lack of native wit and

intelligence that prevented them from solving messages enciphered by the USMTC route ciphers.

Third, it is possible that Confederate high commanders were not interested in communications

intelligence operators or in gathering the fruits of

such operations. Such an explanation seems on its

face fatuous and wholly unacceptable. We know of

the high estimate of value field commanders placed

upon the interception and solution of tactical messages transmitted by visual signaling; but an appreciation of the extraordinary advantages of learning

the contents of enemy communications on the

strategic level may have been lacking. My colleague,

Mr. Fishel, thinks that “intelligence consciousness”

and “intelligence sophistication” were of a very low

order in the Union army, and of a markedly lower

order in the Confederate army. But to us, in 1961, to

disregard the advantages of a possible reading of

strategic messages seems almost incredible, and I

am inclined to discount this sort of explanation.

Fourth, it is possible that Confederate cryptanalysts were far more successful in their efforts to

solve USMTC transmissions than present publicly

available records indicate; that Confederate commanders obtained great advantages from their

communications intelligence operations; that they

fully recognized the supreme necessity of keeping

this fact and these advantages secret; and that the

Confederate States government adopted and

Page 88
enforced strict communications intelligence security regulations, so that the truth concerning these

matters has not yet emerged. Let it be noted in this

connection that very little information can be found

in the public domain today about Allied cryptanalytic successes during World War I; and were it not

for the very intensive and extensive investigations

in the matter of the Japanese attack on Pearl

Harbor on 7 December 1941, very little, if any,

information would be known to the public about

British and American successes in communications

intelligence during World War II. Immediately following the capture of Richmond and before

Confederate records could be removed to a safe

place, a great fire broke out and practically all those

records were destroyed. It is possible that this is

one of the reasons why the records of their communications intelligence successes have never come to

light. But it is also possible that Confederate cryptanalysts kept their secrets to themselves. We know

that the records possessed or taken by certain

Confederate leaders have been gone over with great

care and attention, but what happened to those

retained by other Confederate leaders, such as

Secretary of War Seddon or his predecessor Judah

P. Benjamin, who later became secretary of state,

and others? Here is a fascinating speculation and

one that might well repay careful, painstaking

research in the voluminous records of our National

Archives. I shall leave the delving into those records

to some of you young and aspiring professional crytanalysts who may be interested in undertaking

such a piece of research. With this thought I bring

this lecture to a close.

NOTES

1. And, of course, the G.I.s of those days had a pet

name for the users of the system. They called them “flag

floppers.”

2. This reversal can be seen in figure 53.

3. Ruled paper was provided to aid in accuracy. In

the diagram the upper of each pair of lines of writing is

the cipher, the lower one, the plain text. Simon Cameron

was Lincoln’s secretary of war until January 1862, when

he was replaced by Edwin M. Stanton. If this message

cited by Plum is authentic, and there is no reason to

doubt this, then Cameron was still in friendly contact

with Lincoln, possibly as a special observer.

4. It was the usual practice to use for address and signature the names of the USMTC operators concerned,

5. The series was then put out in book form under

the same title by the Appleton-Century Company, New

York, 1907, reprinted in 1939.

6. In searching for a good example, my eye caught

the words “Lincoln shot” at the left of the matrix and I

immediately thought that the message had to do with

Booth’s assassination of the president. But after hurriedly translating the message and finding nothing in it having anything to do with the shooting, it occurred to me to

look up the indicators for a matrix of six rows and eight

columns. They turned out to be LINCOLN (message of

eight columns), SHOT (6 rows). The word SMALL

beneath the “Lincoln shot” is a variant for SHOT, also

meaning “6 rows.”

7. A key word is employed to change the alphabets

cyclically, thus making the cipher what is called today a

periodic polyalphabetic cipher controlled by the individual letters of a key, which may consist of a word, a

phrase, or even of a sentence, repeated as many times as

necessary.

8. Battles and Leaders of the Civil War (New York:

The Century Co., 1884), 581.

9. A curious coincidence – or was it fortuitous foreshadowing of an event far in the future? – can be seen in

the sequence of the last two words of the cipher text. The

message is dated September 30, 1862; the New York

Herald and the New York Tribune combined to make

the New York Herald-Tribune on March 19, 1924–62

years later!

10. I should warn you that it contains several errors!

11. Op. cit., 206.

12. My emphasis. W.F.F.

Page 89
Page 90
For a half century following the close of the Civil

War, cryptology in the United States enjoyed a period of hibernation from which it awoke at long last

about 1914, not refreshed, as did Rip Van Winkle,

but weaker. This is perhaps understandable if we

take into account that the United States was able to

enjoy a long era of peace, broken only briefly by the

short war with Spain in 1898. For over three

decades there was little or no need for cryptology in

the United States government, except for the communications of the Department of State. The military and naval services apparently felt that in time

of peace there was no need for either cryptography

or cryptanalysis, and since it looked as though the

United States was going to enjoy peace for long, an

indefinitely long time, those services did not think

it necessary to engage in theoretical cryptologic

studies. Of course, the War Department and the

Army still had those route ciphers and cipher disks

described in the preceding lecture; the Navy

Department and the Navy had cipher disks for producing simple monoalphabetic ciphers; and the

State Department had a code more or less specifically designed for its communications. Separated

from Europe by the broad Atlantic, and mindful of

General Washington’s policy of noninvolvement in

the problems of European diplomacy, America followed the traditional and easy course of isolationism. The quarrels among the countries in Europe

were none of our business, and America turned its

back to them for a half century, uninvolved and

unconcerned.

There was, however, in this long hibernating

period in U.S. cryptology one episode of particular

interest. It concerned a presidential election in

which the circumstances paralleled the election of

1960, when the very small popular-vote majority of

the Democratic candidate suggested a possible

upset in the electoral college voting. The episode to

which I refer occurred nearly a century ago, in the

presidential election of 1876, in which Democratic

candidate Samuel J. Tilden was pitted against

Republican candidate Rutherford B. Hayes. On the

basis of early evening election returns, Tilden

seemed to be easily the winner. Indeed, just before

going to bed on election night, 8 November 1876,

Hayes conceded the election to Tilden, and the

newspapers the next morning followed this lead

and reported a Tilden victory. But when final tallies

began coming in, they showed that the closeness of

the popular vote made Tilden’s victory not as sure

as his supporters had calculated, and they therefore

began to become apprehensive about their candidate’s victory. Their apprehensions were valid

because of our peculiar system of electing a president, peculiar because it is the electoral and not the

popular vote which determines who is to be the

next occupant of the White House. Two days after

the people had voted, it became clear that Tilden

would have 184 electoral votes, just one short of

insuring victory, whereas Hayes would have only

163, thus needing twenty-two more. The Tilden

supporters began a frantic campaign to get that one

additional vote they needed, and they didn’t hesitate to try every possible ruse to obtain it, including

bribery, a rather serious piece of business and one

obviously requiring a good deal of secrecy, especially in communications. Of course, many telegrams

had to be exchanged between the Tilden headquarters in New York City and confidential agents who

had to be sent to certain states where one or more

electoral votes could perhaps be purchased;

telegrams also had to be exchanged among those

secret agents in the field. About 400 telegrams were

exchanged, and some 200 of these were in cryptographic form. Communication difficulties caused

two almost consummated bribery deals to fall

through; and a third deal failed because the electors

proved to be honest Republicans not susceptible to

Page 91

Lecture V
monetary temptation. The existence of these

telegrams, however, remained unknown to the

public for months. We shall come to them later.

Despite the efforts of the Tilden supporters, the

outcome of the election remained in doubt because

four states – Florida, South Carolina, Louisiana,

and Oregon – each sent two groups of electors, an

event not foreseen or provided for in the

Constitution. A crisis arose, and the country

seemed to be on the verge of another civil war. By

an act of 29 January 1877, Congress created a special electoral commission to investigate and decide

upon the matter of the disputed electoral votes in

the four states. Recounts of votes in certain election

precincts were made, sometimes aided by soldiers

of the Federal army. The commission voted in favor

of the Hayes electors in each case, and having

obtained the needed twenty-two electoral votes,

Hayes entered the White House.

It was only some months afterward that the

telegrams to which I have referred were brought to

light, and a situation arose which Congress felt it

had to look into. Somehow or other, in the summer

of 1878, copies of those telegrams had come into

the possession of a Republican newspaper in New

York, The Tribune. Interested only in ascertaining

the truth, the editor put two members of his staff on

the job, and they succeeded in solving those

telegrams that were in cipher.

Various books dealing with the political aspects

of his intriguing story are available in public

libraries, but those of you who are interested only in

its cryptologic aspects will find excellent material in

the following four documents:

[1] “The Cipher Dispatches,” The New York

Tribune, Extra No. 44, New York, (14 January)

1879.

[2] Hassard, John R.G., “Cryptography in

Politics,” The North American Review, Vol CXXVIII, No. 268, March 1879,315-25.

[3] Holden, Edward S., The Cipher Dispatches,

New York, 1879.

[4] U.S. House Miscellaneous Documents, Vol.

5, 45th Congress, 3rd Session, 1878-79. The lastmentioned item, that put out by the congressional

committee which had been designated to conduct

the investigation (and which was named “The

Select Committee on alleged frauds in the

Presidential Election of 1876”) is of special interest.

In the course of the investigation, the committee

solicited the technical assistance of Professor

Edward S. Holden, of the United States Naval

Observatory in Washington, the author of the third

item listed above, who, I believe, was a captain in

the navy and had specialized in mathematics. The

Tribune had brought him into the picture by asking

his help when solution seemed hopeless, but it

turned out that Mr. John R.G. Hassard, the chief of

The Tribune staff, and his colleague, Colonel

William M. Grosvenor, also of that staff, solved the

ciphers independently and, in fact, shortly before

Professor Holden solved them, although it was the

latter that the congressional committee called upon

to explain matters, as would only be natural under

the circumstances.

Professor Holden’s testimony, in which he set

forth his solution of the nearly 200 cryptograms

entered in evidence, is presented in the form of a

letter to the committee, dated 21 February 1879. In

it he described and explained all the cryptosystems

used, together with their keys and full details of

their application. In that letter, Professor Holden

makes the following statement: “By September 7,

1878, I was in possession of a rule by which any key

to the most difficult and ingenious of these

[ciphers] could infallibly be found.” Most of the

ciphers involved word transpositions and Holden

worked out the keys, but in this he had been anticipated by the Tribune cryptanalysts. There were in

all ten different keys, two for messages of 10, 15, . .

words, up to and including two for messages of thirty words. On the following page will be found the

complete “Table of Keys.”

Page 92
You may be wondering why there are two

transposition keys for each pair of messages from

ten to thirty words, in multiples of 5. The two keys

constituting a pair are related to each other, that is,

they bear a relationship that Mr. Hassard, one of

the Tribune cryptanalysts, termed “correlative,”

but which we now would call an “encipher-decipher” or a “verse-inverse” relationship. Either

sequence of a correlative pair of sequences may be

used to encipher a message; the other can then be

used to decipher the message. For example, key 111

consists of the following series of numbers: 8-4-1-

7-13..., etc., and the correlative, key IV, is 3-7-12-2-

6. . ., etc. A cipher message of fifteen words can be

deciphered either by (1) numbering its words consecutively and then assembling the words in the

other 8-4-1-7-13, or by (2) writing the sequence 3-

7-12-2-6. . . above the words of the cipher message

and then assembling the numbered words according to the sequence 1-2-3-4-5 . . . . Thus, there

were, in reality, not ten different transposition

keys but only five. In the case of each pair of keys,

one of them must have been the basic sequence,

the other the inverse of it, or at least some derivative thereof.

I suspect that the basic or “verse” sequences of

numbers were not drawn up at random but were

derived from words or phrases; and I think that

they were the odd-numbered ones because, as you

will notice, it is in the odd-numbered keys that the

positions of sequent digits reflect the presence of an

underlying key word or phrase; this is not true in

the even-numbered keys. I have not seriously

attempted to reconstruct the key words, but perhaps some of you may like to try and will succeed in

doing so.

In addition to transposition, this system

involved the use of “arbitraries” to represent certain

words, the names of important persons and places,

etc. There were also a few nulls. 

Professor Holden adds some comments about

this system that are worth quoting:

The essence of this ingenious and novel

system consists in taking apart a sentence

written in plain English (dismembering it,

as it were) and again writing all the words

in a new order, in which they make no

sense. The problem of deciphering it consists in determining the order according to

which the words of the cipher should be

written in order to produce the original

message.

There is one way, and only one way, in

which the general problem can be solved,

and that is to take two messages, A and B,

of the same number of words, and to number the words in each; then to arrange

message A with its words in an order

which will make sense, and to arrange the

words of message B in the same order.

There will be one order – and only one – in

which the two messages will simultaneously make sense. This is the key.

Page 93

Fig. 70
Here, in a nutshell, we find the basic theory of

solving transposition ciphers by anagramming

messages of the same length, explained in a most

succinct manner.

It appears that Professor Holden, clever as he

was, did not note the verse-inverse relation in each

pair of sequences, or if he did, he failed to mention

it in his testimony. However, Hassard [2] specifically points this out.

There were enough messages in this system to

make it possible to solve codewords used, as well as

to recognize a few nulls which were occasionally

added to complicate matters. Hence, the most complicated of the cryptosystems involved in this

bizarre political episode were solved.

Another system used by the conspirators

employed a bilateral substitution, that is, one in

which a pair of cipher letters represents a single letter. This substitution was based upon a 10 x 10

checkerboard. Apparently neither Professor

Holden nor the Tribune cryptanalysts recognized

the latter principle, nor did they find that the coordinates of the checkerboard employed a key phrase,

nor did they realize that the same checkerboard,

with numerical coordinates, was used for a numerical substitution alphabet in which pairs of digits

represent letters of the alphabet.

Here are two of the messages exchanged by the

conspirators, one in letter cipher, the other in the

figure cipher The messages are long enough for

solution. Try to solve them, reconstruct the matrix

and find the key phrase from which the coordinates

of the matrix were derived. It should amuse you by

its appropriateness.

The message in letter cipher is as follows:

The example in figure cipher is as follows:

There were several other systems involved in

this episode of political skullduggery, but I am

going to pass them by because they hardly deserve

attention in this brief history. I do, however, want

to call your attention to the very close resemblance

between the word-transposition ciphers characterized by Professor Holden as the “most difficult and

ingenious” of the ciphers he solved, and the USMTC

route ciphers described in the preceding lecture.

Yet, not only he but also the Tribune amateur cryptPage 94

Jacksonville, Nov. 16 (1876)

Geo. R Raney, Tallahassee:

PP YY EM NS HY YY PI MA SH NS YY SS

IT EP AA EN SH NS SE US SH NS MM PI

YY SN PP YE AA PI EI SS YE SH AI NS SS

PE EI YY SH NY NS SS YE PI AA NY IT NS

SH YY SP YY PI NS YY SS IT EM EI PI MM

EI SS EI YY EI SS IT EI EP YY PE EI AA SS

IM AA YE SP NS YY IA NS SS EI SS MM PP

NS PI NS SN PI NS IM IM YY IT EM YY SS

PE YY MN NS YY SS IT SP YY PE EP PP

MA AA YY PI IT L’Engle goes up tomorrow.

(Signed) Daniel

Jacksonville, Nov. 17 (1876)

S. Pasco and E. M. L’Engle:

84 55 84 25 93 34 82 31 31 75 93 82 77 33

55 52 93 20 90 66 77 65 33 84 63 31 31 93

20 82 33 66 52 48 44 55 42 82 48 89 42 93

31 82 66 75 31 93

(Signed) Daniel
analysts solved those ciphers without too much difficulty, even though they were technically more

complex. I think their work on the Tilden ciphers

clearly confirms my own appraisal of the weakness

of the route ciphers used by the USMTC in the Civil

War. 

After this digression into the realm of what may

be called political cryptology, let us now go on with

our military cryptologic history. I have already told

you that the Department of State used a code for

cryptographic communications in the years following the Civil War, but I do not know what it was like.

It may even have been an adaptation of some commercial code. But in an article entitled “Secret

Writing,” which appeared in Century Magazine,

Vol. LXXXV, November 1912, No.1, a man named

John H. Haswell, apparently at that time a code

clerk in the Department, referred to a new code of

the Department in the following terms:

The cipher of the Department of State is

the most modern of all in the service of the

Government. It embraces the valuable features of its predecessors and the merits of

the latest inventions. Being used for every

species of diplomatic correspondence, it is

necessarily copious and unrestricted in its

capabilities, but at the same time it is economic in its terms of expression. It is simple and speedy in its operation, but so

ingenious as to secure absolute secrecy.

The construction of this cipher, like many

ingenious devices whose operations

appear to be simple to the eye but are difficult to explain in writing, would actually

require the key to be furnished for the purpose of an intelligible description of it.

Only four years later a certain telegraph operator and code clerk of the State Department proved

how vulnerable the Department’s system of enciphered code really was. His name was Herbert O.

Yardley (fig. 71), and many of you may know a bit

about him as the author of a famous or infamous

book (depending upon whose side you’re on) entitled The American Black Chamber, published in

Indianapolis by the Bobbs-Merrill Co. in 1931. So

far as I know, it is the only book that cannot be

legally reprinted in the United States because a special law passed in 1934 makes it a criminal offense

to do so. That is quite a story in itself, but I cannot

tell it now. If you happen to own a copy of the first

and only American edition, don’t let it get away

from you, because you can obtain another copy of it

only by a more or less “under the table” deal; but

you may be able to purchase a British edition, or a

translation in French, in Japanese, or in other languages, for the book was sensational. But to return

to that State Department cryptosystem, which was

considered by Haswell as giving absolute secrecy

and which was readily solved by Yardley, here is

what appears on the cover page of Yardley’s twentyone-page typewritten analysis and solution of the

system:

THEORY AND PRACTICE OF 

ENCIPHERED CODE

State Department Problems

I, II, and III

Note: The following was written in March

1916 and, so far as I can learn, is the first

successful attempt to solve a problem in

enciphered code.

H.O. Yardley

Page 95

Fig. 71
Yardley was quite wrong in thinking that his

was the first successful attempt to solve a problem

in enciphered code, for in Europe more complicated cases were often solved, and I imagine that

European cryptanalysts could have read, and perhaps did read, State Department messages as a

more or less routine matter. I think I am warranted

in assuming that what I have just said is true

because, in Europe, cryptanalytic studies were

going on apace during the years of American neglect of such studies. The turning point from neglect

to a renaissance of interest in cryptographic studies

in Europe is said by some authorities to have been

about the year 1880; but we must confine ourselves

for the most part to developments in America, in

order to keep this lecture within bounds of what can

be told in a limited time.

In our navy it seems that simple monoalphabetic ciphers continued in use until the middle of the

eighties, when several naval officers were designated to prepare a more suitable system, based upon a

code particularly designed for naval communications. The system they worked out was embodied in

a very large codebook, 18” long, 12” wide, and 2”

thick, which had the official title The U.S. Navy

Secret Code. There was also an accompanying but

separate cipher book, almost as large, designated as

The Book of Key Words. In addition to these was a

third large book called General Geographical

Tables. The system was placed into effect on 1

December 1887. Later I will show you a most historic message sent in that system of secret communication, which today impresses one as being

extraordinarily clumsy and slow.

In our army, in the middle of the eighties, a code

was also prepared. It is no pleasure to have to tell

you that its composition and format hardly shed

laurels upon those responsible for its reproduction,

because it was merely a simple and acknowledged

adaptation of a commercially available small code

for use by the general public, first published in 1870

with the title Telegraphic Code to Ensure Secresy

[sic] in the Transmission of Telegrams. It had been

compiled by the secretary of the French TransAtlantic Telegraph Company, a man named Robert

Slater, and it became known everywhere as

“Slater’s Code.” As to the nature of the code, I will

quote from Slater’s own “Short explanation of the

mode of using this work,” in a sort of preface to the

2nd Edition:

It is a numbered Telegraphic Dictionary of

the English language, of which each word

bears a distinctive No. (from 00001 to

25000, with exactly 100 words per page),

and the method of using it is by an interchange of Nos., in accordance with a private understanding between correspondents that a further No. is to be added to or

deducted from the number in the code, of

the word telegraphed or written, to indicate the real word intended, that a

‘Symbolic’ or ‘Dummy Word’ is

telegraphed, the meaning of which can

only be read by those who have the key

to the secret of how many should be added

to or deducted from the original number

in the Code, of the ‘Dummy Word’ to find

the word meant. (Punctuation as in the

original)

Here we have a sentence of 116 words. Though

it is rather long and a bit murky, I think you will

gather its import. The system as thus far described

is what we now call the additive or subtractive

method. But in the detailed instructions Slater goes

one step further and suggests that instead of

telegraphing the code number resulting from addition or subtraction of a key number, the word

standing alongside the sum (or difference) of the

mathematical operation be sent as the telegraphic

code. Slater’s code must have met with popular

acclaim because by 1906 it was in its fifth edition. A

copy of the second edition (1870) is in my collection. As for a copy of the very first edition, not even

the Library of Congress has one, it’s that scarce.

To get on with the story, in 1885 the War

Department published an adaptation of Slater’s

Code for its use and the use of the Army. Here is the

Page 96
picture of its title page, the only difference between

it and that of Slater’s Code being in the spelling of

the word “secrecy,” as you can easily see in the picture I. show you next (fig. 72). It would appear that

the “compiler” of this code, Colonel Gregory, was

just a bit deficient in imagination. Not only did he

merely borrow the basic idea and format of Slater’s

Code, but even when it came to explaining and giving examples of enciphering the code groups, the

colonel used not only the identical rules but also the

very same wording and even the very same type of

examples of transformations that are found in

Slater’s original. Let me show you an example of

Slater’s code side by side with the same example in

Gregory’s. (See fig 73.)

You will note that Colonel Gregory just couldn’t

use the same text for his examples of encipherment

that Slater used, which was “The Queen is the

supreme power in the Realm.” Instead he used the

enigmatic text “War is a punishment whereof death

is the maximum.”1

All the other methods and examples of encipherment in the two codes are practically identical.

Colonel Gregory gives credit in the following terms

to a civilian aide in his great work: “The labor of

compiling the new vocabulary has been performed

by Mr. W. G. Spottswood.” What did the latter do?

Well, Mr. Spottswood’s work consisted of casting

out from Slater’s list such words as ABALIENATE

and ABANDONEE and replacing them with such

words as ABATEMENT and ABATIS. This sort of

work must indeed have been arduous. I’m sorry to

appear to be critical of the performance of my predecessors in the construction of codes and code systems for War Department and Army usage, but I

feel sure you will agree that more imagination and

Page 97

Fig. 72
ingenuity could have been employed than were

used by Colonel Gregory and Mr. Spottswood.

Colonel Gregory prepared a confidential letter

addressed to Lieutenant General Sheridan,

“Commanding Army of the United States,” to

explain the advantages of the new code. But in this

letter Colonel Gregory quotes very largely from

Holden’s little brochure [3] and deals almost solely

with the ways in which additional security may be

gained by changing the additives to the code numbers in Slater’s Code. For example, for all messages

sent in January add 111; for all messages sent in

February add 222, in March 333, etc. Another suggested way: “Send out a simple message in ordinary

English: Add 1437 to all ciphers until further

orders.”

Believe it or not, this was the code that the War

Department and the Army used during the

Spanish-American War. It was apparently used

with a simple additive, because in a copy in my collection the additive is written on the inside of the

front cover. It is 777; perhaps it was the additive for

the month of July, but the number 777 was written

in ink, so it may have been the permanent additive

for the whole of the war. In pages 41-42 of The

American Black Chamber, the author throws an

interesting sidelight on this code system:

The compilation of codes and ciphers was,

by General Orders, a Signal Corps function, but the war [1917] revealed the unpreparedness of this department in the United

States. How much so is indicated by a talk

I had with a high officer of the Signal Corps

who had just been appointed a military

Page 98

Fig. 73
attaché to an Allied country. It was not

intended that attachés should actually

encode and decode their own telegrams,

but as a part of an intelligence course they

were required to have a superficial knowledge of both processes in order that they

might appreciate the importance of certain

precautions enforced in safeguarding our

communications.

When the new attaché, a veteran of the old

Army, appeared, I handed him a brochure

and rapidly went over some of our methods of secret communications. To appreciate his attitude, the reader should understand that the so-called additive or subtractive method for garbling a code

telegram (used during the SpanishAmerican War) is about as effective for

maintaining secrecy as the simple substitution cipher which as children we read in

Foe’s ‘The Gold Bug.’

He listened impatiently, then growled:

‘That’s a lot of nonsense. Whoever heard of

going to all that trouble? During the

Spanish-American War we didn’t do all

those things. We just added the figure 1898

to all our figure code words, and the

Spaniards never did find out about it.’

Although The American Black Chamber

abounds with exaggerations and distortions, what

the author tells about the inadequacies of United

States codes and ciphers in the years just before our

entry into World War I is true enough, and

Yardley’s impatience and satiric comments in this

regard, it grieves me to say, are unfortunately fully

warranted.

During or perhaps shortly after the end of the

Spanish-American War, the War Department must

have begun to realize that there were shortcomings

in the code based upon Slater’s Code, the one which

was in current usage and upon which I have already

dwelt. On 16 January 1898 the publication of a new

War Department Telegraphic Code was authorized

by General Orders No.9. The code was to be prepared under the direction of General A. W. Greely,

then Chief Signal Officer of the Army. The cited

General Order makes it quite clear that the War

Department version of Slater’s Code was still in use,

but the Western Union Telegraphic Code was to be

used in connection with Slater’s until the new War

Department Code was completed; it apparently was

ready in December 1899, when Slater’s was withdrawn from use with this statement in General

Orders No. 203: “By direction of the Secretary of

War, the Telegraphic Code to Insure Secrecy in the

Transmission of Telegrams, will on and after

January 15, 1900, only be used for correspondence

in such cases as may be specially ordered by the

Secretary of War.” On 12 December 1899 the new

War Department Code was issued. Here is a picture

of its title page (fig. 74). It comprised a specially

compiled list of tables, words, phrases, and sentences to which code numbers and code words were

assigned for specific use in War Department and

Army communications. The code numbers began

with 78201 and went to 95286; the accompanying

code words were foreign, outlandishly unusual real

words, and artificial words, beginning with KOPERKIES, KOPERKLEURS, KOPERMOLEN, etc.,

etc., down through the L’s, M’s and ending with

words such as NAZWELGEN, NEANTHE,

NEAPELGELB, etc., etc. You may wish to know

why the code numbers didn’t begin with 00000

and go to 99999; or why the code groups began

with K and went for thousands and thousands of

words down to N. The answer is that this brand new

War Department Telegraphic Code was to be used,

as Slater’s Code was used, in conjunction with the

Western Union Telegraphic Code, a code of 78,200

groups beginning with numerical code groups

00000 accompanied by literal code words beginning with BEERKAR, BEERKARREN, BEERMELD... and going to KOOT JONGEN,

KOOTKRUID, KOOTSPEL. Here is a picture of a

typical page in this code (fig. 75).

The introduction to this code explains this puzzling fact: 

Page 99
Through lack of time it has been impossible to incorporate in the War Department

Telegraphic Code all desirable phrases,

and in consequence the first 471 pages of

the Western Union Telegraphic Code now

in use by the Army will continue in use as a

supplementary code. This affords the

Army the telegraphic use of 100,000 code

words, of which numbers 1 to 78,201,

inclusive, are in the Western Union

Telegraphic Code and numbers 78,201 to

100,000 are in the War Department

Telegraphic Code.

It thus becomes clear that for several years the

new War Department Code was to be used in conjunction with the commercially available large

Western Union Telegraphic Code. This was stated

to be for the purpose of economy. For secrecy, the

additive or subtractive method was to be used. The

futility of such an old and simple method for

achieving communications security needs no comment. I wish there were time to read you the

instructions in that new War Department

Telegraphic Code regarding the use of these

ciphers for secrecy. They are practically the same as

those in the 1885 version of Slater’s Code and are

unbelievably futile, but what else could be expected

when cryptology is relegated to a position in military science far inferior to that of teaching the use of

a rifle or bayonet, subjects which are taught, as a

rule, by experts? Why was cryptology left to inexperienced amateurs during all those years? Was it stupidity? No, just a lack of appreciation of the importance of secure communications in military operations – and a lack of enough people with the requisite know-how.

How long this combination of two codes continued to be used I don’t know, Sometime from 1900

to 1915 this absurd system must have proved itself

entirely unsatisfactory, for in 1915 another brand

new War Department Telegraph Code was put out,

under direction of Brigadier General George P.

Scriven, the Chief Signal Officer of the Army who

succeeded Greeley. A picture of its title page can be

seen on page 99. (fig. 76). The book bears no security classification, for even as late as 1915 there was

no real or definite classification system for security

purposes. The instructions recommended certain

precautions. “The War Department Telegraph

Code,” says paragraph 5 of the instructions, “while

not absolutely confidential, will be guarded with the

greatest care and will never be out of the immediate

possession or control of the officer to whom issued

or of his confidential agent. Care will be taken to

prevent theft, loss, use, or inspection except by 

Page 100

Fig. 74

Fig. 75
those whose duties require them to employ the

code. Special pains will be taken to prevent the code

from falling into the hands of unauthorized persons

or of the enemy.”

This new code was intended, as was its predecessor, to serve two purposes: “First, secrecy and

second, economy. When secrecy is desired it is to be

used as a cipher code, as is explained in subsequent

paragraphs under ‘Enciphered Code’.” But there

are no subsequent paragraphs in which this is

explained. Apparently some change in this regard

was decided, because I have seen, as a separate

pamphlet, a set of cipher tables for use with this

code.

The code itself embodied some of the latest

ideas of code compilation. It had over 113,000 code

groups, and these were both five-figure groups and,

for the first time, five-letter groups. The latter

embodied the principle of the two-letter difference,

but the instructions do not mention this fact, and

no permutation table was included in the code

itself. The book has a very extensive vocabulary of

words, phrases, and sentences. Here is a picture of

a typical page (fig. 77). I feel sure that a great deal of

thought and effort went into the production of this

code, but I must tell you two things about it. First, I

must tell you that my immediate predecessor in the

Office of the Chief Signal Officer told me, on my

return from France in 1919, that that particular edition of the War Department Telegraph Code had

been printed in Cleveland by a commercial printer,

and, second, that when the United States became a

belligerent in World War I, our British allies found

it desirable to notify the U.S. government (through

our G-2) that our War Department Telegraph Code

was not safe to use, even with its superencipherment tables. The implications of this notification

are rather obvious and hardly require comment.

The compilation of a new code in 1917 was initiated,

but this time the work was done within and under

the direction of the Military Intelligence Division of

the General Staff (G-2), and in particular within the

section devoted to cryptanalysis. This undertaking,

which indubitably was a direct affront to the Signal

Page 101

Fig. 76

Fig. 77
Corps of the Army, met with no objection, it seems,

from that group; perhaps it deserved the intended

insult because of its long-standing neglect of its

clear responsibilities for cryptography and cryptographic operations in and for the Army.

We have noted how inadequately the Army and

the War Department were equipped for cryptocommunications from 1885 to 1915. Let us see how well

equipped the Navy and the Navy Department were.

For this purpose I have an excellent example and

one of great historical significance and interest. You

will recall my mention of the appointment of a

board of navy officers to prepare a suitable cryptosystem for the Navy, and I told you about the

large basic vocabulary and tabular contents of the

codebook and its accompanying two large books,

one for enciphering the code groups, the other for

geographical names. For the story we go back to the

time of President McKinley, whose election brought

Theodore Roosevelt, a former member of the Civil

Service Commission, back to Washington as assistant secretary of the navy. Teddy was an ardent

advocate of military and naval preparedness. He

forthrightly and frankly favored a strong foreign

policy, backed by adequate military and naval

strength – “speak softly but carry a big stick” was

his now-famous motto. He was looking forward, in

fact, to forcing the ultimate withdrawal of the

European powers from the Western Hemisphere.

With vigor, he set to work to make the Navy ready.

When the battleship Maine was blown up in

Havana harbor on 15 February 1898, Roosevelt

sharpened his efforts. During a temporary absence

of his chief, Navy Secretary John D. Long, he took it

upon himself to initiate the preparations which he

had in vain tried to persuade the secretary to make.

He ordered great quantities of coal and ammunition, directed the assembling of the Fleet, and

stirred the arsenals and navy yards into activity. On

a miserably cold Saturday afternoon, ten days after

the Maine was blown up, and still in the absence of

Secretary Long, Teddy sat down and wrote out a

cablegram to go to Commodore George Dewey at

Hong Kong.You can see it above, with his bold signature at the bottom (fig. 78).

That is the now historic message that alerted

Dewey and that resulted in our taking over the

Philippine Islands under U.S. protection in the war

with Spain, which was declared ten days later.

You will note that the message bears on its face

a security classification, but the classification,

“Secret and Confidential,” was crossed out. That

must have been many years later, for those three

Page 102

Fig. 78
words appear in the plain text of the deciphered

and decoded cablegram. Below is a picture of the

code cablegram with its strange and outlandish

code words, as it was received in Hong Kong 

(fig. 79).

And now I show you the deciphered and decoded text, which I was fortunate in being able to produce by courtesy of the chief of the Naval Security

Group, who permitted me to consult and use the

necessary codebooks that I found were still in Naval

Security Group archives (fig. 80).

To translate a message in the code then in use,

three steps are necessary. First, the cable words

(the peculiar, outlandish words in line 2 –

WASSERREIF, PAUSATURA, BADANADOS, etc.)

are sought in the cipher book and their accompanying cable-word numbers set down. WASSERREIF

yields 99055; PAUSATURA yields 62399,

BADANADOS, 11005, etc. The next step is to

append the first digit of the second cable-word

number to the last digit of the first cable-word

number to make the latter a six-digit number. Thus

99055 becomes 990556. The six-digit code group

number 990556 is then sought in the basic codebook, and its meaning is found to be “Secret and

Confidential.” The transfer of the first digit, 6, of the

second cable-word number, 62399, makes it

become code-number 2399, to which must now be

appended the first two digits of the third cableword number, 11005, thus making the second code

group of the code message 239911, which is sought

in the basic codebook and yields the meaning

“Order the squadron.” And so on. It’s painfully slow

work, and I haven’t told you about some of the difficulties I encountered in the process, including

having to refer to the third book, the General

Geographical Tables, It took me at least an hour to

decipher and decode this relatively short Roosevelt

message. I feel sure a naval operation in World War

II or in World War I, for that matter, could never

have been executed before a message even as brief

as the Roosevelt one could be deciphered and

decoded by this cumbersome system, even if all the

digits had been transmitted and received correctly,

Generally speaking, naval battles are fierce and

quickly over. For instance, on 4 June 1942, between

10:24 and 10:26 a.m., the war with Japan was

decided when the U.S, Pacific Fleet under Admirals

Nimitz, Fletcher, and Spruance won the Battle of

Midway, in which the Japanese lost four fast carriers, together with their entire complement of

planes, and almost all their first-string aviators.

When our navy entered World War I, a much more

practical system was put into effect, using a cipher

device known as the NCB, standing for “Navy

Cipher Box,” to encipher five-letter groups of a

basic code.

We come now to European events of importance in this cryptologic history. During the

decades from the end of the Civil War in America to

the first decade of the twentieth century, there was

some progress in cryptologic science in Europe, but

it was not of a startling nature. German Army Major

Kasiski’s demonstration of a straightforward,

mathematical method of solving the Vigenère 

Page 103

Fig. 79
Page 104

Fig. 80
cipher was published in Berlin during the mid-period of the Civil War in America. If the book created

an impression in Europe, it was altogether unspectacular; in America it remained unheard of until

after the advent of the twentieth century. Although

Kasiski’s method is explained quite accurately in

the first American text on cryptology,2 the name

Kasiski doesn’t even appear in it. Other books on

cryptologic subjects appeared in Europe during this

period, and two of them deserve special attention.

The first, by Commandant Bazeries, is a book

notable not for its general contents, which are presented in a rather disorganized, illogical sequence,

but for its presentation of a cipher device invented

by the author, the so-called “cylindrical cipher

device.” But our own Thomas Jefferson anticipated

Bazeries by a century, and the manuscript describing his “Wheel Cypher” is among the Jefferson

Papers in the Library of Congress. The second book,

which deserves special attention, is one by another

French cryptologist, the Marquis de Viaris, in which

he presents methods for solving cryptograms prepared by the Bazeries cipher cylinder, and 

although unknown to him, the ciphers of

Jefferson’s Wheel Cypher.3 It was in the period during which books of the foregoing nature were written and published that the chanceries of European

governments operated so-called “Black Chambers,”

organized for solving one another’s secret communications. Intercept was unnecessary because the

governments owned and operated the telegraph

systems, and traffic could be obtained simply by

making copies of messages arriving or departing

from telegraph offices or passing in transit through

them. This was true in the case of every country in

Europe with one very important exception: Great

Britain. The story, which is given in detail in a

recently published and very fully documented

book,4 is highly interesting, but I must condense it

to a few sentences.

In England, from about 1540 until 1844, a

“black chamber” was in constant operation. It was

composed of three collaborating organizations

within the Post Office respectively called “The

Secret Office,” “The Private Office,” and “The

Deciphering Branch.”

In the first of these carefully hidden secret

organizations, letters were opened, copies of them

were made, the letters replaced, the envelopes

resealed, and if the wax seals were intact they were

merely replaced. If the seals were not replaceable,

duplicates were forged and affixed to the envelopes.

Copies of letters in cipher were sent to the

“Deciphering Branch” for solution and the results,

if successful, were then sent to the Foreign Office. A

famous mathematician, John Wallis, took part in

the latter activities. The “Private Office” took care of

similar activities, but only in connection with internal or domestic communications. In 1844, a scandal involving these secret offices caused Parliament

to close them down completely, so that from 1844

until 1914 there was no black chamber at all in

Britain. As a consequence, when World War I broke

out on the first of August 1914, England’s black

chamber had to start from scratch. But within a few

months British brains and ingenuity built a cryptologic organization known as “Room 40 O.B.,” which

contributed very greatly to the Allied victory in

1918. Although the British government has never

issued a single official publication on the activities

and accomplishments of “Room 40 O.B.,” several

books by private authors have pushed aside the curtain of secrecy to make a most fascinating story too

long to tell in this lecture. But I must tell you at least

something about what was perhaps the single

greatest achievement of “Room 40 O.B.,” an

achievement which just in the nick of time brought

this country into World War I as an active belligerent on the Allied side and saved England, as well as

France, from possible destruction.

The operation involved the interception and

solution of a message known as the Zimmermann

Telegram, deservedly called the most important

single cryptogram in all history. On 8 September

1958 I gave before an NSA audience a detailed

account of this amazing cryptogram. I told about its

interception and solution; I told how the solution

was handed over to the United States; how it

Page 105
brought America into the war on the British side;

and how all this was done without disclosing to the

Germans that the plain text of the Zimmermann

Telegram had been obtained by interception and

solution by cryptanalysis, that is, by science and not

by treason. My talk was given under the auspices of

the NSA Crypto-Mathematics Institute, was recorded, and is on file so that, if you wish, you can hear

it. It took two and a half hours to deliver, and at that

I didn’t quite succeed in telling the whole story. But

you may read an excellent account of this episode,

set forth in great detail in a book entitled The

Zimmermann Telegram, by Barbara Tuchman,

published in 1958 by the Viking Press, New York.

Also, you should consult a book entitled The Eyes of

the Navy, by Admiral Sir William James, published

in 1955 by Methuen & Co., London. Both books deal

at length with the Zimmermann Telegram and tell

how astutely Sir William Reginald Hall, Director of

British Naval Intelligence in World War I, managed

the affair to get the maximum possible advantage

from the feat accomplished by “Room 40 O.B.” It

was, indeed, astounding!

To summarize, as I must, this fascinating and

true tale of a very important cryptanalytic conquest,

let me show you again the telegram as it passed

from Washington to Mexico City, for if you will

remember, I showed it to you in the very first lecture of this series, and promised to tell you about it

later. Here I show it to you once again [See Figure

86]. As you can easily see, the code groups are composed of three-, four-, and five-digit groups, mostly

the latter. Here is the English decoded translation

of the message as transmitted by Ambassador Page

in London to President Wilson:

Foreign Office Telegraphs Jan 16, No.1.

Most secret. Decipher yourself.

We intend to begin unrestricted submarine warfare on the first of February. We

shall endeavour in spite of this to keep the

United States of America neutral. In the

event of this not succeeding, we make

Mexico a proposal of alliance on the following basis. Make war together, make

peace together, generous financial support

and an understanding on our part that

Mexico is to reconquer the lost territory in

Texas, New Mexico and Arizona. The settlement in detail is left to you. You will

inform the President (of Mexico) of the

above most secretly as soon as the outbreak of war with the United States of

America is certain, and add the suggestion

that he should, on his own initiative, invite

Japan to immediate adherence, and at the

same time mediate between Japan and

ourselves. Please call the President’s attention to the fact that the ruthless employment of our submarines now offers the

prospect of compelling England, in a few

months, to make peace.

ZIMMERMANN

From the day that Ambassador Page sent his

cablegram to President Wilson, on 28 February

1917, quoting the English translation of the

Zimmermann Telegram in the form in which had

been forwarded by German ambassador von

Bernstorff in Washington to German minister von

Eckhardt in Mexico City, the entrance of the United

States into the war as a belligerent on the side of the

Allies became a certainty. Under big black headlines the English text appeared in our newspapers,

because, after assuring himself of the authenticity

of the telegram handed over by the British and that

it had been decoded and checked by a member of

Ambassador Page’s own staff, President Wilson

directed that the text of the message be released to

the Associated Press. Its publication the next day

was the first of a momentous and sensational series

of reports and accounts of the Zimmermann

Telegram and its contents.

There were plenty of members of Congress who

disbelieved the story. But when Zimmermann himself foolishly acknowledged that he had indeed sent

such a telegram, disbelief changed quickly into

most vehement anger. Thus, it came about that

Page 106
Americans in the Middle West and Far West, who

had thus far been quite unconcerned about a war

that was going on in Europe, thousands of miles

away, and wanted no part of it, suddenly awoke

when they learned that a foreign power was making

a deal to turn over some rather large slices of U.S.

real estate to a then hostile neighbor across the

southern border. They were aroused to the point

where they, too, as well as millions of other

Americans in the East, were ready to fight. Surely

war would now be declared on Germany. 

Notwithstanding all the furor that the disclosure of the Zimmermann Telegram created in

America, President Wilson still hesitated. He was

still determined that America would not, must not,

fight. It was not until more than a month later, and

after several American ships were sunk without

warning on 18 March, that a now fully aroused

President got Congress to declare war on Germany

and her allies. The date was 6 April 1917.

In the War Department and in the Navy

Department, the pace set for preparing for active

war operations quickened. It is difficult to believe,

but I assure you that it was true, there was at the

moment in neither of those departments, nor in the

Army or Navy, any organizations or technical

groups whatever, either for intercepting enemy

communications or for studying them, let alone

solving such communications. There had been, it is

true, since the autumn of 1916, a very small group

of self-trained cryptanalysts, sponsored and supported by a private citizen named Colonel George

Fabyan,5 who operated the Riverbank Laboratories

at Geneva, Illinois. I served as leader of the group,

in addition to other duties as a geneticist of the

Laboratories. Riverbank, through George Fabyan,

had initiated and established an unofficial, or at

most, a quasi-official relationship with the authorities in Washington, so that it received from time to

time copies of cryptographic messages obtained by

various and entirely surreptitious means from telegraph and cable offices in Washington and elsewhere in the United States. At that period in our

history, diplomatic relations with Mexico were in a

sad state, so that U.S. attention was directed southward, and not eastward across the Atlantic Ocean.

Therefore, practically all the messages sent to

Riverbank for solution were those of the Mexican

government. Riverbank was successful in solving

all or nearly all the Mexican cryptograms it was

given, usually returning the solutions to

Washington very promptly. The great majority of

them were of the Vigenère type but using mixed

sequences with relatively long key phrases.

Riverbank was also successful with certain other

cryptograms which were concerned with the war in

Europe, but I cannot deal with them now because

there just isn’t time. Soon after the United States

declared war on Germany, Colonel Fabyan established a school for training at Riverbank, and he

invited the services to send him army and navy officers to learn something about cryptology in formal

courses established for the purpose. Each course

lasted about six weeks, full time.

You may like to know what we novices used for

training ourselves for this unusual task and what

we used later on for training the student officers

Page 107

Fig. 81
Page 108

sent to us for cryptologic instruction. As regards our

self-instruction training material, there wasn’t

much available in English, but among the very

sparse literature was that small book by Captain

Parker Hitt, called Manual for the Solution of

Military Ciphers, to which I referred earlier.

Colonel Fabyan managed to get a copy of that manual for us to study. The Signal Corps School was

then one of the army service schools, and there a

few lectures were given by two or three officers

who, when World War I broke out in August 1914,

took an interest in the subject of military cryptography. They foresaw that sooner or later there would

be a need for knowledge in that important branch

of military technology. Captain Hitt’s manual was

then, and still is, a model of compactness and pracFig. 82

Fig. 84

Fig. 83

Fig. 85
ticality. Let me show you the title page of the first

edition (fig. 82). 

It was the succinctness of Parker Hitt’s manual

that caused us much work and perspiration in our

self-training at Riverbank, but we later came to

know and admire its author, whose photograph I

now show you as he looked when he became a

colonel in the Signal Corps (fig. 83).

There was one other item of training literature

which we also studied avidly. It was a very small

pamphlet entitled An Advanced Problem in

Cryptography and its Solution, and it too was put

out by the Fort Leavenworth Press in 1914. Its title

page is shown in figure 84. You will note that its

author was then First Lieutenant J.O. Mauborgne;

he advanced to become major general and Chief

Signal Officer of the Army (fig. 85). The “advanced

problem” dealt with in that pamphlet was the

Playfair Cipher I about which I shall say only that at

the time Mauborgne wrote about that particular

cipher it was considered to be much more difficult

than it is at present.

Returning now to what Riverbank’s self-trained

cryptanalytic group was able to do in a practical

way in the training of others, there exist in NSA

archives copies of the many exercises and problems

prepared at Riverbank for this purpose. They are, I

think, still of much interest as curiosities of U.S.

cryptologic history.

In Lecture II, I showed you a picture of the last

of the several classes sent by the Army to Riverbank

for training. It should be noted, and it gives me considerable pleasure to tell you, that this instruction

was conducted at Colonel Fabyan’s own expense as

his patriotic contribution to the U.S. war effort. I

can’t, in this lecture, say much more about this than

it involved the expenditure of many thousands of

dollars, never repaid by the government – not even

by income-tax deduction or by some decoration or

similar sort of recognition. Upon completion of the

last training course, I was commissioned a first

lieutenant in Military Intelligence, General Staff,

and was ordered immediately to proceed to

American General Headquarters in France, where I

became a member of a group officially referred to as

the Radio Intelligence Section. But it was the

German Code and Cipher Solving Section of the

General Staff, a designation that was abbreviated as

G-2, A-6, GHQ-AEF. As the expanded designation

implies, the operations were conducted in two principal sections, one devoted to working of German

army field ciphers, the other, to working on

German army field codes. There were also very

small groups working on other material such as

meteorologic messages, direction-finding (DF)

bearings, and what we now call traffic analysis, that

is, the detailed study of “the externals” of enemy

messages in order to determine enemy order of battle and other vital intelligence from the study of DF

bearings, the direction, ebb and flow of enemy traffic, and other data sent back from our intercept and

radio direction-finding operations at or near the

front line in the combat zone.

In connection with the last-mentioned operations, you will no doubt be interested to see what is

probably one of the earliest, if not the very first,

chart in cryptologic history that shows the intelligence that could be derived from a consideration of

the results of traffic analysis. Its utility in deriving

intelligence about enemy intentions from a mere

study of the ebb and flow of enemy traffic, without

being able to solve the traffic, was of unquestionable value. Here’s that historic chart (fig. 86), which

I must tell you was drawn up from data based solely upon the ebb and flow of traffic in what we called

the ADFGVX cipher,6 a clever cryptosystem that

was devised by German cryptographers and which

was restricted in its usage to German High

Command communications, principally those

between and among the headquarters of divisions

and army corps. Its restriction to such high command messages made a study of its ebb and flow

very important. Theoretically, that cipher was

extremely secure. It combined both a good substitution and an excellent transposition principle in

one system without being too complicated for

cipher clerks. Below is a diagram which will give a

Page 109
clear understanding of its method of usage.

[Regarding this system], in this lecture there is only

time to tell you that although individual or isolated

messages in the ADFGVX system then appeared to

be absolutely impregnable against solution, a great

many messages transmitted in it were read by the

Allies.

You may be astonished by the foregoing statement and therefore may desire some enlightenment here and now on this point. In brief, there

were in those days three and only three different

methods of attacking that cipher. Under the first

method, it was necessary to find, as the first step,

two or more messages with identical plaintext

beginnings because they could be used to uncover

the transposition, which was the second step. Once

this had been done, the cryptanalyst had then to

deal with a substitution cipher in which two-letter

combinations of the letters A, D, F, G, V, and x represented single plaintext letters. The messages were

usually of sufficient length for this purpose. Under

the second method, two or more messages with

identical plaintext endings could be used to uncover the transposition. This was easier even than in

the case of messages with identical beginnings. You

might think that cases of messages with identical

beginnings or endings would be rather rare, but the

addiction to stereotypic phraseology was so prevalent in all German military communications that

there were almost invariably found, in each day’s

traffic, messages with similar beginnings or endings, and sometimes both. Under the third method

of solution it was necessary to find several messages

with exactly the same number of letters. This happened, but not often. This system first came into

use on 1 March 1918, three weeks before the last

and greatest offensive by the German army. Its

appearance was coincident with that of other new

codes and ciphers. The number of messages in the

ADFGVX cipher varied from about twenty-five a

day, when the system first went into use, to as many

as about 150 a day at the end of two months. It took

about a month to figure out a method of solution,

and this was first done by a very able cryptanalyst

named Captain Georges Painvin of the French

army’s Cipher Bureau. 

The ADFGVX cipher was used quite extensively

on the Western Front with daily changing keys during May and June of 1918, but then, for reasons

somewhat obscure, the number of messages

dropped very considerably. How many different

keys were solved by the Allies during the four

Page 110

Fig. 86
months from 1 March to the end of June? Not many

– ten in all; that is, the keys for only ten different

days were solved. Yet, because the traffic on those

days was very heavy, about fIfty percent of all messages ever sent in that cipher, from its inception to

its discard, were read, and a great deal of valuable

intelligence was derived from them. On one occasion, solution was so rapid that an important

German operation disclosed by one message was

completely frustrated.

Although the ADFGVX cipher came into use

first on the Western Front, it later began to be

employed also on the Eastern Front, with keys that

were first changed every two days but later every

three days. On 2 November 1918 the key for that

and the next day was solved within an hour and a

half because two messages with identical endings

were found. A thirteen-part message in that key

gave the complete plan of the German retreat from

Romania.

During the eight months of the life of the

ADFGVX cipher, solution depended upon the three

rather special cases I mentioned. No general solution for it was thought up by the Allies despite a

Page 111

Plain text: REQUEST REENFORCEMENTS IMMEDIATELY

Second Letter

A D F G V X

A

D

F

G

V

X

Bilateral Substitution:

R E Q U E S T R E E N F O R C E

XD AF AA AD AF AV AX XD AF AF DG GF DF XD FV AF

M E N T S I M M E D I A T E L Y

VF AF DG AX AV DA VX VX AF GA DA DV AX AF FF FG

Key Word:

Q U I C K B R O W N F O X J U M P E D

14 16 6 2 8 1 15 11 18 10 5 12 19 7 17 9 13 4 3

Substituted Text:

Y D A F A A A D A F A V A X X D A F A

F D G G F D F X D F V A F V X A F D G

A X A V D A V X V X A F G A D A D V A

X A F F F F G

Transposed Text:

ADAFF GVFAG AFDVA VAAGA FXVAA FDFDA AFFXD XXVAF

AFDXF AXAFV GDDXA XXDAD VAFG

Q U E 5 S T

I 9 0 N A 1

B 2 L Y F 3

D 4 F 6 G 7

H 8 J O K M

P R V W X Z
great deal of study. However, members of our own

Signal Intelligence Service, in 1933, devised a general solution and proved its efficacy. Pride in this

achievement was not diminished when, in the

course of writing up and describing the method, I

happened to find a similar one in a book by French

General Givierge (Cours de Cryptographie, published in 1925). Givierge was by then the head of the

French Black Chamber, which was called the

“Deuxieme Bureau,” corresponding to our “G-2.”

The ADFGVX cipher was not the only one used

by the German army in World War I, but there will

be time to mention very briefly only two others. The

first of these was a polyalphabetic substitution

cipher called the “Wilhelm,” which used a cipher

square with disarranged alphabets and with a set of

thirty fairly lengthy key words. The cipher square is

shown in figure 87. Just why the square contains

only twenty-two rows instead of twenty-six is probably connected with the fact that German can get

along very well with fewer than twenty-six letters.

Certainly the rows within the square are not random sequences, as you can see, for the letters within them manifest permuted arrangements in sets of

five letters. In figure 88 are shown the keys used –

thirty of them. The key sequences seem to be composed of random letters, but underlying them is

plain text. I leave it to you to try to reconstruct the

real square, if possible. You should be able to reconstruct the real keys, for the latter problem should be

relatively easy.

The other German army cipher to be mentioned

is the double transposition, an example of which is

shown below. The process consists in applying the

same transposition key twice to the same matrix,

once horizontally and once vertically, as seen in this

slide. Solution of the true double matrix transposition usually depends upon finding two or more

messages of identical length. (You will remember

what I told you about Captain Holden in this connection.) No general solution was known to the

Allies during World War I, and messages of identical length were few indeed. But it happened that

occasionally a German operator would apply only

the first transposition, and when this fortunate situation occurred solution was easy, because the key

thus recovered from the single transposition could

be used to decipher other messages which had been

correctly enciphered by the double transposition.

Again, the Signal Intelligence Service devised a general solution for the double transposition cipher,

and during World War II we were able to prove that

such ciphers could be solved without having to find

two messages of identical length. I think the devising of a general solution for the true double transposition cipher represents a real landmark of

progress in cryptanalysis.

We come now to the code systems used by the

belligerents in World War I. First, let us differentiate those used for diplomatic communications from

those used for military communications. What

sorts did the German Foreign Office use? We have

noted that the British Black Chamber, “Room 40

O.B.,” enjoyed astonishing success with the code

Page 112

First transposition Second transposition Final Cryptogram

Literal key: B U R E A U

Derived nunerical key: 2 5 4 3 1 6 2 5 4 3 1 6 ATFKC NOOTU

A T T A C K C P N U A P ADMNS SPLIT

P O S T P O N I A A T U ERPUT O

N E D U N T O T S D F T

I L F O U R O E L M K O

A M T R

Double transposition
used for the transmission of the Zimmermann

Telegram. Excessive pride in German achievements

in science, a wholly unjustified confidence in their

communication cryptosecurity, and a disdain for

the prowess of enemy cryptanalysts laid German

diplomatic communications open to solution by the

Allies to the point where there came a time when

nothing the German Foreign Office was telling its

representatives abroad by telegraph, cable, or radio

remained secret from their cryptologic antagonists.

For those of you who would like to learn some

details, I refer you to the following monograph on

the subject by my late colleague, Captain Charles J.

Mendelsohn: Studies in German Diplomatic Codes

Employed During the World War (Government

Printing Office, 1937). Says Dr. Mendelsohn:

At the time of America’s entrance into the

war German Codes were an unexplored

field in the United States. About a year

later we received from the British a copy of

a partial reconstruction of the German

Code 13040 (about half of the vocabulary

of 19,200 words and 800 of the possibly

7,600 proper names). This code and its

variations of encipherment had been in

Page 113

Numbers were expressed by the following letters bracketed between “Q’s”:

1 2 3 4 5 6 7 8 9 0

H P J W D Y V R A F

The alphabet beginninng “SQRYV” was known as the “A” alphabet; that beginning “LOPNM” as “B” alphabet, etc.

Messages numbered 1, 31, 61, etc. were decipherable by the 13 alphabets in the order “JVCEPQHCMPQGP.”

Messages numbered 2, 32, 62, etc. were decipherable by the 13 alphabets in the order “TBUULENFKEQGC.”

The horizontal sequence above the table is the plain-text sequence. The vertical alphabet on the extreme left gives

the arbitrary symbol by which the different alphabets were known in the 30 keys.

Attached is a list of these 30 keys:

Fig. 87
use between the German Foreign Office

and the German Embassy in Washington

up to the time of the rupture in relations,

and our files contained a considerable

number of messages, some of them of historical interest, which were now read with

the aid of the code book.

The vocabulary of the German diplomatic codes

comprised about 189 pages, each having 100 words

or expressions to the page, arranged in two

columns of fifty each, accompanied by numbers

from 00 to 99. In each column the groups were in

blocks of ten. In the left-hand column, for instance,

were the five blocks from 00-99, 10-19, etc., to 40-

49. Then 50-59, 60-69, etc., were in blocks often in

the right-hand column. The pages in the basic code

were numbered, and from this code several codes

were made by the use of conversion tables. This

enabled the original or basic code to serve as the

framework for apparently unrelated and externally

distinguishable codes for several different communication nets. What the number of the basic code

was is unknown, but we do know that from the 

code designated as Code 13040 came codes 5950,

26040, and others, derived merely by means of

tables for converting the page numbers in the 

basic code into different page numbers in the

derived code. These conversions were systematic,

in blocks of fours. Thus, for example, pages 15-18 in

code 13040 became pages 65-68 in code 5950, etc.

The there were tables for converting line numbers

from one code into different line numbers in another version of the basic code, and this was done in

blocks often. For example, the fifth block (penultimate figure 4) became the first (penultimate figure

0), and the 1st, 2nd, 3rd, and 4th blocks were

moved down one place. The other five blocks (on

the right hand side of the page) were rearranged in

the same manner.

It is obvious that codes derived in such a manner from a basic code by renumbering ages and

shifting about the contents of pages in blocks can by

no means be considered as being different and

entirely unrelated codes, and once a relationship

between two such codes was discovered, the two

could be handled as equivalents of one another.

Also to be mentioned is that in certain cases numbers were added to or subtracted from the code

Page 114

It will be noticed that the same letter, as P, for

instance, as in key no. 1, is repeated four different times.

Again, the E and Q and G which occur in 1 also occur in 2.

These facts pointed to the use in these 30 keys of intelligible

German words. The arbitrary letters, which the keys in their

present form contained, represented a simple substitution.

This appeared from the frequency, for example, of G and the

inseparable combinations NF and NA, N nevery appearing

unless followed by F or A. It was therefore probable that these

letters, arbitrarily chosen to represent the 22 different alphabets, in reality represented keywords in German text.

N was assumed to be the value of C, and F, H; and G,

the most frequent letter which was never absent from any of

the series, E. This simple substitution was continued until

familiar German syllables began to appear and finally the

complete key words themselves.

Fig. 88
numbers of a message, and this gave rise to what

seemed to be still different codes. It was not difficult to determine the additive or subtractive and

thus get to the basic code numbers.

In none of the cases of codes mentioned thus far

was there one that could be considered to be a randomized, “hatted,” or true two-part code, since the

same book served for both encoding and decoding.

However, the German Foreign Office later on did

compile and use real two-part, truly randomized

codes of 10,000 groups numbered from 0000 to

9999. One such code had as its indicator the number 7500. And that there were several others like it

I have no doubt.

When one reviews Dr. Mendelsohn’s monograph, one becomes overwhelmed by the multiplicity of the codes and variants thereof used by the

German Foreign Office. Some were basic codes, but

many were derivatives or superencipherments

thereof. It is even hard to ascertain the exact number of different codes and superencipherment

methods. Yet a great deal of the traffic in these

codes was read. Considering the rather small number of persons on the cryptanalytic staff of G-2 in

Washington and in the British counterpart organization in London, the British Black Chamber, one

can only be astonished by the remarkably great

achievements of these two collaborating organizations that worked on German diplomatic codes during World War I.

So much for German diplomatic secret communications. What about German military cryptocommunications? I have already mentioned several systems used, but these were developed two or more

years after the outbreak of World War I. When

World War I commenced, the German army was

very poorly prepared to meet the requirements for

secure communications. It seems that up until the

Battle of the Marne in 1914 several army radio stations went into the field without any provision having been made, or even foreseen, for the need for

speedy and secure cryptocommunications.

Numerous complaints were registered by German

commanders concerning extensive loss of time

occasioned by the far too complicated methods officially authorized for use and the consequent necessity for sending messages in the clear. Not only did

this reveal intelligence of importance to their opponents, but, what is equally important, the practice

permitted the British and the French to become

thoroughly familiar with the German telegraphic

procedures, methods of expression, terminology

and style, and the knowledge gained about these

items became of great importance in cryptanalysis

when German cryptosystems improved. The

German army learned by hard experience something about its shortcomings in this area of warfare

and not only soon began to improve, but did so to

the point where we must credit the Germans with

being the initiators of new and important developments in field military cryptography. In fact, the

developments and improvements began not long

after the Battle of the Marne and continued steadily until the end of the war. When on 11 November

the armistice ended active operations, German military cryptology had attained a remarkable high

state of efficiency. The astonishing fact, however, is

that, although very proficient in cryptographic

inventions, they were apparently quite deficient in

the science and practice of cryptanalysis. In all the

years since the end of World War I, no books or

articles telling of German successes with Allied

radio traffic during that war have appeared; one

Austrian cryptanalyst, a man named Figl, attempted to publish a book on cryptanalysis, but it seems

to have been suppressed. One could, of course,

assume that they kept their successes very well hidden, but the German archives taken at the end of

World War II contained nothing significant in

regard to cryptanalysis during World War I,

although a great deal of important information in

this field during World War II was found. A

detailed account of the cryptologic war between the

Allied and German forces in World War II would

require scores of volumes, but there is one source of

information that I can highly recommend to those

of you who would like to know more details of the

cryptologic warfare between the belligerents in

World War I. That source is a book written and

Page 115
published in Stockholm in 1931 by a Swedish cryptanalyst, Yves Gylden, under the title

Chifferbråernas Insatser I Varldskriget Till Lands,

a translation of which, with some comments of my

own in the form of footnotes, you will find under

the title The Contribution of the Cryptographic

Bureaus in the World War (Government Printing

Office, 1936).

In this lecture, however, we are principally concerned with German military cryptology during

World War I, and since I have already told you

something about the cipher systems that were used,

there remain to be discussed the field codes. It was

the German army that first proved that the old idea

that code books were impractical for use in the

combat zone for tactical communications was

wrong. They had two types of field codes: one they

called the SCHLUESSELHEFT but that we called

the “three-number code,” the other that they called

the SATZBUCH but that we called the “three-letter

code.” The former was a small, standardized code

with a vocabulary of exactly 1,000 frequently used

words and expressions, digits, letters and syllables,

etc., for which the code equivalents were three-digit

numbers. A cipher was applied only to the first two

digits of the code numbers; this cipher consisted of

two-digit groups taken from a 10 x 10 matrix for

enciphering the numbers from 00 to 99. This table

was called the GEHEIMKLAPPE or “Secret Key,”

and here’s a picture of one (fig. 89). The last digit of

a code group remained unenciphered. Thus, code

group 479 would become 629. Each division compiled and issued its own secret key table, which was

in two parts, or sections, of course, one for encipherment, the other for decipherment. The threenumber code was intended for use in all forms of

communication within, or to and from, a threekilometer front-line danger zone. Although this

code was completed by the end of January 1918, it

was not distributed or put into use until the opening day of the last and greatest German offensive,

10 March 1918. Our code-solving section, through

good fortune and careful attention, ascertained the

nature of the new code, and a few groups in it were

solved the very same day the code was put into

effect, because a German cipher operator who was

unable to translate a message in the new code

requested and received a repetition in another code

that had been solved to an extent that made it possible to identify homologous code groups in both

messages. The three-number code proved rather

easy to solve on a daily basis because only the encipher-decipher table was changed. Much useful

intelligence was obtained from the daily solution of

this key.

Page 116

Fig. 89
The solution of the SATZBUCH, or three-letter

code, however, proved to be a much more difficult

problem. In the first place, it had a much larger

vocabularv, with nulls and many variants for frequently used words, letters, syllables, and numbers,

in the second place, and what constituted the real

stumbling block to solution, was that it was a true

two-part randomized or “hatted” code; and in the

third place, each sector of the front used a different

edition of the code, so that not only did the traffic

have to be identified as to the sector to which it

belonged but also it was not possible to combine all

the messages for the purpose of building up frequencies of usage code groups. Here is a typical

page of one of these codes (fig. 90). Working with

the sparse amount of traffic within a quiet sector of

the front and trying to solve a few messages in this

code was really a painfully slow, very difficult and

generally discouraging experience. On my reporting for duty to Colonel Frank Moorman, who was

chief of the whole unit, I was asked whether I

wished to be assigned to the cipher section or to the

code section Having had considerable experience

with the solution of the former types of cryptosystems but none with the latter, and being desirous of

gaining such experience, I asked to be assigned to

the code-solving unit, in order to broaden my professional knowledge and practice in cryptology.

Little did I realize what a painful and frustrating

period of learning and training I had undertaken,

but my choice turned out to be a very wise and useful one. If any of you would like to read about my

experience in this area, let me refer you to my

monograph, written in 1918-1919, entitled Field

Codes Used by the German Army During the

World War. I will quote the last two paragraphs

from my “estimate of the three-letter code” (on p.

65 of that monograph) and will remind you that

although they were written over forty years ago they

are still applicable:

In the light of this limited experience (of

less than six months with the 3-letter code)

it is impossible to say absolutely what the

degree of security offered by such a highly

developed system really is. There is no

doubt but that it is very great. There is no

doubt but that, with the proper precautions, careful supervision and control the

employment of such a code by trained men

offers the highest possible security for

secret communication on the field of battle.

But no code, no matter how carefully constructed, will be safe without tramed,

intelligent personnel. A poorly constructed code may be in reality more safe when

used by an expert than a very well constructed one when used by a careless operator, or one ignorant of the dangers of

Page 117

Fig. 90
improperly encoded messages. This pomt

cannot be overemphasized. It is hardly

necessary to point out, therefore, that the

proper traming of the personnel which is

to be put in charge of the work of coding

messages is an essential requisite to maintenance of secrecy of operations, and thus

of success on the field of battle.

So much for the German army field codes,

about which a great deal more could be said, but we

must hurry on to the cryptosystems of some of the

other armies of World War I.

What sorts of cryptosystems did the French

army use? First, as for ciphers, they put much trust

in transposition methods, and here is an example of

one type (fig. 91). Perhaps you remember one of

those special route ciphers I showed you in the preceding lecture, the one with the diagonal that produced complexities that made the use of that route

much too difficult for the cipher operators of the

USMTC. This French transposition cipher was

much more complicated by those diagonals, and I

wonder how much use was made of it by the

French.

As for codes, like the Germans, they used a

small, front-line booklet called a “Carnet Reduit,”

or an “Abbreviated Codebook.” Various sectors of

the front had different editions, and I show you now

a picture of one of them (fig. 92). Then, in addition,

there was a much more extensive code, which was

not only a two-part, randomized book of 10,000

four-digit code groups but a superencipherment

was applied to the code messages when transmitted

by radio or by “TPS,” that is “telegraphie par sol,” or

earth telegraphy. Here is one of the tables used for

enciphering (and deciphering) the code groups (fig.

93), and here is the example ofsuperencipherment

given in the French code in my collection (fig. 94).

You will notice that the enciphering process

breaks up the four-digit groups in a rather clever

manner by enciphering the first digit of the first

Page 118

Fig. 91
code group separately; the second and third digits

of the first group are enciphered as a pair; then the

last digit of the first group and the first digit of the

second code group are enciphered as a pair, and so

on. This procedure succeeds in breaking up the digital code groups in such a manner as to reduce very

greatly the frequency of repetition of four-digit

groups representing words, numbers, phrases, etc.,

of very common occurrence in military messages.

My appraisal of this French army field cryptosystem is that, theoretically at least, it certainly was the

most secure of all the field systems used by the belligerents.Now how about the cryptosystems used

by the British army? First, they used the Playfair

Cipher, a system of digraphic substitution considered in those days to be good enough for messages

in the combat zone. But today, of course, its security is known to be so low that it hardly merits confidence for serious usage. The British also used a field

code. It contained many common military expressions and sentences, grouped under various headings or categories, and, of course, a very small

vocabulary of frequently used words, numbers,

punctuation, etc. It was always used with superencipherment, the nature of which was not disclosed

even to us, their allies, so I am not in a position 

Page 119

Fig. 92
Page 120

Fig. 93
to describe it. We did not even have a copy of their

code – only a typewritten transcript which was furnished us quite reluctantly. This next slide was

made by setting up in print a typical page thereof

(fig. 95).

As for the Italians, the general level of cryptologic work in Italy during the period was quite low,

a fact that is all the more remarkable when we consider that the birthplace of modern cryptology was

in Italy several centuries before. There appears to

have been in Italy a greater knowledge of cryptologic techniques in the fifteenth and sixteenth centuries than in the nineteenth, paradoxical as this

may seem to us today. Perhaps this can be considered as one of the consequences of the need for

secrecy that requires filing away in dusty archives

records of cryptanalytic successes; but it is to be

considered also that this prevents those who might

have a flair for cryptologic work from profiting from

the progress of predecessors who have been successful in such work. We should not be too astonished to learn, therefore, that when Italy entered

World War I the Italian army put its trust in a very

simple variation of the ancient Vigenère cipher, a

system called the “cifrario militare tascabile,” or the

“pocket military cipher” (fig. 96). It, as well as several others devised by the same Italian “expert,”

was solved very easily by Austrian cryptanalysts

during the war. The Italian army also used codes,

no doubt, but since encipherment of such codes

consisted in adding or subtracting a number from

the page number on which a given code group

appeared, the security of such systems was quite

illusory. As late as 1927 the same Italian “expert”

announced his invention of an absolutely indecipherable cipher system that, Gyldén says (p. 23),

“still further demonstrates the astonishing lack of

comprehension of modern cryptanalytic methods

on his part.”

As regards Russian cryptographic work, it is

known that there was, during the era of the last of

the Czarist rulers, an apparently well-organized and

effective bureau for constructing and compiling

diplomatic codes and ciphers, which had been

organized by a Russian named Savinsky, formerly

Russian minister to Stockholm. He saw to it that all

codes and ciphers in use were improved; he introPage 121

Fig. 94

Fig. 95
duced strict regulations for their use; and he kept

close watch over the cryptographic service. He also

was head of a cryptanalytic activity, and it is known

that Turkish, British, Austrian, and Swedish diplomatic messages were solved. After the Bolshevik

revolution of 1916, some of the Russian cryptanalysts managed to escape from their homeland, and

I had the pleasure of meeting and talking with one

of the best of them during his service with one of

our allies in World War II. He is no longer alive, but

I vividly recall that he wore with great pride on the

index finger of his right hand a ring in which was

mounted a large ruby. When I showed interest in

this unusual gem, he told me the ring had been presented him as a token of recognition and thanks for

his cryptanalytic successes while in the service of

Czar Nicholas, the last of the line.

But the story is altogether different as regards

cryptology in the Russian army. The Military

Cryptographic Service was poorly organized, and,

besides, it had adopted a cryptographic system that

proved to be too complicated for the poorly trained

Russian cipher and radio operators to use when it

was placed into effect toward the end of 1914. Here

is a picture of that cipher (fig. 97), which was composed of two tables, one arranged for convenience

in enciphering and the other arranged for convenience in deciphering. In the enciphering table the

letters of the Russian alphabet (thirty-three in all)

appwear in the topmost row of characters, the twodigit groups, in random order within each of the

eight rows below the top row, are their cipher

equivalents. These rows therefore constitute a set of

eight cipher alphabets, these alphabets being preceded by key numbers from 1 to 8 in random order.

Both the cipher equivalents and the indicators were

subject to change. Indicators were used to tell how

many letters were enciphered consecutively in each

alphabet, the indicator consisting of one of the digits from 1 to 9 repeated five times. The alphabets

were then used in key-number sequence, enciphering the first set of letters (5, 7, etc., according to the

indicator) by alphabet I, the next set by alphabet 2,

and so on. After the eighth set of letters, which was

enciphered by cipher alphabet 8, one returned to

Page 122

Fig. 96
cipher alphabet I, repeating the sequence in this

manner until the entire message had been enciphered. In enciphering a long message, the cipher

operator could change the number of letters enciphered consecutively by inserting another indicator

digit repeated five times and then continuing with

the next alphabet in the sequence of alphabets. The

cipher text was then sent in five-digit groups. The

use of the deciphering table hardly requires explanation, but this question may be in order: Why the

aversion to the use of zero and to the use of double

digits such as 11, 22, 33, etc.? This probably was

thought to be helpful to the telegraph operators as

well as to the cipher clerks in straightening out

errors in transmission and reception.

I have told you that this cipher system proved

too difficult for the Russians to use, and I think you

can see why. It was so difficult that messages had to

be repeated over and over, with great loss of time. It

is well known to all historians by this time that the

Russians lost the Battle of Tannenberg in the

autumn of 1914 largely because of faulty communications. Poor cryptography and failure to properly

use even the most simple ciphers on the field of battle, and not brilliant strategy on the part of the

enemy, were the cause of Russia’s defeat in that and

in subsequent battles. The contents of Russian

communications known to the German and

Austrian High Commands within a few hours after

transmission by radio. The disposition and movements of Russian troops and Russian strategic

plans were no secrets to the enemy. The detailed

and absolutely reliable information obtained by

intercepting and reading the Russian communications made it very easy for the German and

Austrian commanders not only to take proper

countermeasures to prevent the execution of

Russian plans but also to launch attacks on the

weakest parts of the Russian front.

Page 123

Fig. 97
Although the Russian ciphers were really not

complicated, their cipher clerks and radio operators

found themselves unable to exchange messages

with accuracy and speed. As a matter of fact, they

were so inept that not only were their cipher messages easily solved but also they made so many

errors that the intended recipients themselves had

considerable difficulty in deciphering the messages,

even with correct keys. In some cases this led to the

use of plain language, so that the German and

Austrian forces did not even have to do anything

but intercept the messages and translate the

Russian. To send out dispositions, impending

movements, immediate and long-range plans in

plain language was, of course, one cardinal error.

Another was to encipher only words and phrases

deemed the important ones, leaving the rest in

clear. Another cardinal error, made when a cipher

was superseded, was to send a message to a unit

that had not yet received the new key, and, on

learning this, to repeat the identical message in the

old key. I suppose the Russians in World War I

committed every major error in the catalog of crypto-criminology. No wonder they lost the Battle of

Tannenberg, which one military critic said was not

a battle but a massacre, because the Russians lost

100,000 men in the three-day engagement, on the

last day of which the Russian commander in chief

committed suicide. Three weeks later another high

Russian commander followed suit, and the Russian

army began to fall apart, completely disorganized,

without leadership or plans. Russia itself began to

go down in ruins when its army, navy, and government failed so completely, and this made way for

the October revolution, ushering in a regime that

was too weak to put things together again. The remnants were picked up by a small band of fanatics

with military and administrative ability. By treachery, violence, and cunning, they welded together

what has now become a mighty adversary of the

Western world, the USSR.

I have left to be treated last in this lecture the

cryptosystems used by the American Expeditionary

Forces (AEF) in Europe during their participation

in World War I.

When the first contingents of the AEF arrived in

France in the summer of 1917, there were available

for secret communications within the AEF but

three authorized means. The first was the extensive

code for administrative telegraphic correspondence, the 1915 edition of the War Department

Telegraph Code, about which I’ve already told you

something. Although it was fairly well adapted for

that type of communication, it was not at all suitable for rapid and efficient strategic or tactical communications in the field, nor was it safe to use without a clumsy superencipherment. The second cryptosystem available was that known as the repeating-key cipher, which used the Signal Corps Cipher

Disk, the basic principles of which were described

as far back as about the year 1500. The third system

available was the Playfair Cipher, which had been

frankly copied from the British, who had used it as

a field cipher for many years before World War I

and continued to use it. In addition to these authorized means, there were from time to time current in

the AEF apparently several – how many, no one

knows – unauthorized, locally improvised “codes”

of varying degrees of security, mostly nil. I show

you one of these in this slide (fig. 98) and will let

you assess its security yourself.

Seen in retrospect, when the AEF was first

organized it was certainly unprepared for handling

secret communications in the field; but it is certain

that it was no more unprepared in this respect than

any of the other belligerents upon their respective

entries into World War I, as I’ve indicated previously in this lecture. This is rather strange because

never before in the history of warfare had cryptology played so important a role as a consequence of

advances in electrical communications technology.

When measured by today’s standards, it must be

said that not only was the AEF on its arrival in

Europe wholly unprepared as to secret communication means and methods and as to cryptanalysis,

but for a limited time it seemed almost hopeless

that the AEF could catch up with the technical

advances both sides had made, because their

British and French allies were at first most relucPage 124
tant to disclose any of their hard-earned information about these vital matters.

Nevertheless, and despite so inauspicious a

commencement, by the time of the armistice in

November 1918, not only had the AEF caught up

with their allies but they had surpassed them in the

preparation of sound codes, as may be gathered

from the fact that their allies had by then decided to

adopt the AEF system of field codes and methods

for their preparation, printing, distribution, and

usage.

Just as the invention of Morse wire telegraphy

had a remarkable effect upon military communications during the American Civil War, as related in

the preceding lecture, so the invention of radio also

played a very important role in field communications during World War I. Now, although it can

hardly be said that all commanders from the very

earliest days of the use of radio in military communications acutely recognized one of the most important disadvantages of radio – namely, that radio

signals may be more or less easily intercepted by

the enemy – it was not long before the consequences of a complete disregard of this obvious fact

impressed themselves upon most commanders,

with the result that the transmission of plain language became the exception rather than the rule.

This gave the most momentous stimulus to the

development and use of cryptology that this service

had ever experienced.

Let us review some of the accomplishments of

the Code Compilation Service under the Signal

Corps, AEF. It was organized in January 1918, and

consisted of one captain, three lieutenants, and one

enlisted man. Until this service was organized, that

is, from the summer of 1917 until the end of that

year, the AEF had nothing for cryptocommunications except those three inadequate means which

I’ve mentioned. When it had been determined that

field codes were needed, little time was lost in getting on with the job that had to be done. Since I had

no part in this effort, I can say, without danger of

being charged with impropriety, that the Code

Compilation Service executed the most remarkable

job in the history of military cryptography up to the

time of World War II.

The first work entrusted to it was the compilation of a so-called “Trench Code,” of which 1,000

copies were printed, together with what were then

called “distortion tables.” These were simple

monoalphabets for enciphering the two-letter

groups of the code. I will show you a picture of a

page of this code (fig. 99) and of one of the “distortion tables” (fig. 100). The danger of capture of

these codes was recognized as being such that the

books were not issued below battalions. Hence, to

meet the needs of the front line, a much smaller

book was prepared and printed, called the “Front

Line Code.” Distortion tables, thirty of them in all,

were issued to accompany this code, of which an

edition of 3,000 copies was printed. But the code

was not distributed, because a study of its security

showed defects. The truth is that AEF cryptographers with personnel inexperienced in cryptanalysis were groping in the dark, with little or no help

from allies. Finally, the light broke through: the

Code Compilation Service began to see the advantages of that German three-letter randomized twopart code I’ve told you about, the one called the

Satzbuch. Here, then, was the origin of the Trench

Codes that were finally adopted and used by the

AEF ,when it was decided that copying and benefitting from the experience of German code compilers

was no dishonor. But the AEF then went them one

better, as you shall now learn. The first code of the

new series of the AEF field codes was known as the

“Potomac Code”; it was the first of the so-called”

American River Series,” and it appeared on 24 June

1918, in an edition of 2,000 copies (fig. 101). It contained approximately 1,700 words and phrases and,

as the official report so succinctly states, “was made

up with a coding and decoding section in order to

reduce the work of the operators at the front.” The

designation “two-part,” “randomized,” or least of

all, the British nomenclature, a “hatted” code, was

still unknown – but the principle was there

nonetheless. Let us see what the official report goes 

Page 125
Page 126

Fig. 98
on to say on this point; let us listen to some sound

and common sense:

The main point of difference from other

Army codes lay in the principle of reprinting these books at frequent intervals and

depending largely upon the rapidity of the

reissuance for the secrecy of the codes.

This method did away with the double

work at the front of ciphering and deciphering, and put the burden of work upon

general headquarters, where it properly

belonged. Under this system one issue of

codes could be distributed down to regiments; another issue held at Army

Headquarters; and a third issue held at

General Headquarters. As a matter of

record this first book, the Potomac, was

captured by the enemy on July 20,just one

month after issuance, but within two days,

it had been replaced throughout the entire

Army in the field.

The replacement code was the Suwanee, the

next in the River Series, followed by the Wabash,

the Allegheny and the Hudson, all for the

American First Army. In October 1918 a departure

in plan was made, and different codes were issued

simultaneously to the First and Second Armies.

This was done in order not to jeopardize unnecessarily the life of the codes by putting in the field at

one time 5,000 or 6,000 copies of anyone issue.

Thus the Champlain, the first of what came to be

the “Lake Series,” for the Second Army, was issued

with the Colorado of the “River Series” for the First

Army; these were followed by the Huron and the

Osage, the Seneca and the Niagara, in editions of

2,500 each.

In addition to the foregoing series of codes were

certain others that should be mentioned, for example, a short code of two-letter code groups to be

used by frontline troops as an emergency code; a

short code list for reporting casualties; a telephone

code for disguising the names of commanding officers and their units, and so on. But there was in

addition to all the foregoing one large code that

must be mentioned, a code to meet the requirements for secure transmission of messages among

the higher commands in the field and between

these and GHQ. This was a task of considerable

magnitude and required several months’ study of

messages, confidential papers concerning organizations, replacements, operations, and of military

documents of all sorts. The code was to be known as

the AEF Staff Code. In May 1918, the manuscript of

this code was sent to press, and the printing job was 

Page 127

Fig. 99
Page 128

Fig. 100
Page 129

Fig. 101
done in one month by the printing facilities of the

AEF Adjutant General. Considering that the code

contained approximately 30,000 words and phrases, accompanied by code groups consisting of fivefigure groups and four-letter groups, the task completed represents a remarkable achievement by a

field printing organization, and I believe that this

was the largest and most comprehensive code book

ever compiled and printed by an army in the field.

More than 50,000 telegraphic combinations were

sent in tests in order to cast out combinations liable

to error in transmission. One thousand copies of

this code were printed and bound. With this code,

as a superencipherment system, there were issued

from time to time “distortion tables.” There

remains only to be said that the war was over before

this code could be given a good workout, but I have

no doubt that during the few months it was in effect

it served a very useful purpose. Moreover, the excellent vocabulary was later used as a skeleton for a

new War Department Telegraph Code to replace

the edition of 1915.

One more code remains to be mentioned: a

“Radio Service Code,” the first of its kind in the

American army. This was prepared in October, to

be used instead of a French code of a similiar

nature. Finally, anticipating the possible requirement for codes for use by the Army of Occupation,

a series of three small codes, identical in format

with the wartime trench codes of the River and

Lake series, was prepared and printed. They were

named simply Field Codes No.1, 2, and 3 but were

never issued because there turned out to be no need

for them in the quietude in Germany after the Army

of Occupation marched into former enemy, but

now very friendly, territory.

I will bring this lecture to a close now by referring those of you who might wish to learn more

about the successes and exploits of the cryptographic organization of the American

Expeditionary Forces in World War I to my monograph entitled American Army Field Codes in the

American Expeditionary Forces during the First

World War (Government Printing Office, 1942). In

that monograph you will find many details of interest which I have had to omit in this talk, together

with many photographs of the codes and ciphers

produced and used not only by the AEF but also by

our allies and enemies during that conflict.

In Lecture IV two USMTC cipher messages

were given, and I said that their solutions would be

presented at the conclusion of the next lecture.

Here they are, both being from Major General Buell

to General-in-Chief Halleck, relating to the relief

and reinstatement of Buell.

Louisville, Ky., September 29,1862

Maj. Gen. Halleck, General-in-Chief:

I have received your orders of the 24th

inst., requiring me to turn over my command to Maj. Gen. G. H. Thomas. I have

accordingly turned over the command to

him, and in further obedience to your

instructions, I shall repair to Indianapolis

and await further orders.

D. C. Buell,

Major-General

Louisville, Ky., September 30,1862

Gen. Halleck:

I received last evening your dispatch suspending my removal from command. Out

of a sense of public duty, I shall continue to

discharge the duties of my command to the

best of my ability until otherwise ordered.

D. C. Buell,

Major-General

NOTES

1. I wonder what that sentence means. It sounds sort

of “anti-American” to me. Punishment to whom? To the

soldiers and sailors and airmen who defend our country?

If not to them. then to whom? To the people of a whole

nation fighting for liberty? I just don’t understand the

sentence. Do you?

Page 130
2. Captain Parker Hitt’s Manual for the Solution of

Military Ciphers, (Fort Leavenworth, Kansas: Army

Service Schools Press, 1916).

3. L ‘art de chiffrer et dechiffrer les depeches

secretes, (Paris, 1893).

4. Kenneth L. Ellis, The Post Office in the Eighteenth

Century: A Study in Administrative History. (London:

Oxford University Press, 1958), 176. In conjunction with

this book one should by all means also read the following

extremely interesting and revealing article by the same

author: “British Communications and Diplomacy in the

Eighteenth Century,” Bulletin of the Institute of

Historical Research, Vol. XXXI, No. 84, Nov. 1958, 159-

67.

5. Honorary title conferred by the governor of

Illinois for Fabyan’s participation as a member of the

Peace Commission that negotiated the Treaty of

Portsmouth, which terminated the Russo-Japanese War

in 1905.

6. Initially this cipher employed only the letters A, D,

F, G, and X, for a matrix of 5 X 5; later, the letter V was

added, for a matrix of 6 X 6, for the 26 letters of the

alphabet plus the ten digits.

Page 131
Page 132
This, the sixth and final lecture in this series on

the history of cryptology, will be devoted to a presentation of the events of importance in that history

from the end of World War I to the end of WorId

War II. It would be entirely too ambitious a project

even to attempt to compress within a lecture of only

fIfty minutes all that should or could be told in that

segment of our history. Briefly, however, it can be

said that the most significant events during that

quarter of a century were directly concerned, firstly, with the advances made in the production of

more complex mechanical, electrical, and electronic cryptographic apparatus and, secondly, with the

concomitant advances in the production of more

sophisticated cryptanalytic apparatus in order to

speed up or to make possible the solution of enemy

communications produced by these increasingly

complex cryptographic machines. These two phases are interrelated because, to use a simple analogy,

cryptography and cryptanalysis represent the

obverse and reverse faces of a single coin.

As to advances in the development and use of

more effective cryptographic apparatus, I will only

note at this point a comment that General Omar

Bradley of WorId War II fame makes in his very

interesting book, A Soldier’s Story:

1

Signal Corps officers like to remind us that

“although Congress can make a general, it

takes communications to make him a commander.”

It is presumptuous to amend General Bradley’s

remark, but this is how I wish he had worded it:

Signal Corps officers like to remind us that

“although Congress can make a general, it

takes rapid and secure communications to

make him a good .commander.”

This will in fact be the keynote of this lecture. In

other words, communications security, or COMSEC, will be its main theme and the one I wish to

emphasize.

But before we take up the cryptographic history

of the years between 1918 and 1946, perhaps a bit

more attention must be devoted to events and

developments of cryptanalytic significance or

importance during this period. By far the most

spectacular and interesting of these are the ones

that were so fully and disastrously disclosed by the

various investigations conducted by the Army and

Navy very secretly while WorId War II was still in

progress, and both secretly and openly after the

close of hostilities. The investigations were intended to ascertain why our army and navy forces in

Hawaii were caught by surprise by the sneak attack

on Pearl Harbor by the Japanese on the morning of

7 December 1941. They were also intended to ascertain and pin the blame on whoever was responsible.

I don’t think I should even attempt to give you my

personal opinion on these complex questions,

which were studied by seven different boards within the services and fmally by the Joint

Congressional Committee on the Investigation of

the Pearl Harbor Attack. I mentioned the latter

investigation in my first lecture and now will add to

what I said then. The committee began its work

early in September 1945 with secret hearings, but

on seventy days between 15 November 1945 and 31

May 1946, open hearings were conducted, in the

course of which some 15,000 pages of testimony

were taken and a total of 183 exhibits received, incident to an examination of forty-three witnesses. In

July 1946 the committee put out a final report of

580 pages containing its findings, conclusions and

recommendations. The report was accompanied by

a set of thirty-nine volumes of testimony and

exhibits. The report was really not a single report:

Page 133

Lecture VI
there was one by the Majority (signed by six

Democratic and two Republican members), and

one by the Minority (signed by two Republican

members). The Minority Report was not nearly as

long as that of the Majority, but it brought into

focus certain troublesome points that still form the

subject of acrimonious discussions and writings by

those who believe the attack was “engineered” by

President Roosevelt and that certain authorities in

Washington were as culpable as were the principal

commanders in the Army and the Navy in Hawaii.

For this lecture, however, it is an interesting fact

that both the Majority and Minority Reports contain glowing tributes to the role played by COMINT

before and during our participation in World War

II. In my first lecture, I presented a brief extract in

this regard, taken from the Majority Report;2 but

here is what the Minority Report says on the subject:3

Through the Army and Navy intelligence

services extensive information was

secured respecting Japanese war plans

and designs, by intercepted and decoded

Japanese secret messages, which indicated the growing danger of war and increasingly after November 26 the imminence of

a Japanese attack.

With extraordinary skill, zeal, and watchfulness the intelligence services of the

Army Signal Corps and Navy Office of

Naval Communications broke Japanese

codes and intercepted messages between

the Japanese Government and its spies

and agents and ambassadors in all parts of

the world and supplied the high authorities in Washington reliable secret information respecting Japanese designs, decisions, and operations at home, in the

United States, and in other countries.

Although there were delays in the translations of many intercepts, the intelligence

services had furnished to those high

authorities a large number of Japanese

messages which clearly indicated the

growing resolve of the Japanese

Government on war before December

7,1941.

Although references to COMINT abound in the

Report of the Majority as well as in the Report of

the Minority, there are also many references having

to do with COMSEC in both reports, as well as in

the thirty-nine accompanying volumes of testimony

and exhibits. Some technical misconceptions with

regard to those subjects are there, too, and it is

quite comprehensible that there should be some on

the part of laymen, but to encounter a serious one

in a book by an experienced high-level commander

in World War II is a bit disconcerting. Listen to this

paragraph from a recent book by General

Wedemeyer, who was one such commander:4

The argument has been made that we

could not afford to let the Japanese know

we had broken their code. But this argument against a Presidential warning does

not hold water. It was not a mere matter of

having broken a specific code; what we had

done was to devise a machine which could

break any [author’s emphasis] code provided it was fed the right combinations by

our extremely able and gifted cryptographers. The Japanese kept changing their

codes throughout the war anyway. And we

kept breaking them almost as a matter of

routine.

I don’t know where General Wedemeyer

obtained his information about that wonderful

machine he mentions. I imagine that there are

many other persons who think there is such a

machine because of all they hear and see about

those marvelous “electronic brains” which are

capable of performing such amazing feats in solving

all kinds of problems. I dare say I won’t be wrong in

assuming that many of you do indeed wish there

were such a machine as that mentioned by General

Wedemeyer. Nobody doubts that electronic digital

computers can do lots of things in cryptologic

Page 134
research, and many persons speculate on the role

they may play in their possible applications in connection with research in future wars.

But let’s leave such speculations, interesting as

they may be, and continue with our history of past

applications. Let’s first dispose of some comments

in the COMINT area of that history, not only on the

events preceding the Pearl Harbor attack, but also

on the military, naval, and air operations which

ensued in the Pacific as well as in the European

Theater.

You will recall that in my first lecture I called to

your attention an article that appeared in the 17

December 1945 issue of Time and that was based

upon a letter the late General Marshall wrote to

Governor Dewey, Republican candidate for president in the 1944 campaign. Here’s how the two

principals looked at that time (fig. 102). In the letter, which was written on 27 September 1944 and

hand-carried by Colonel Carter W. Clarke, a highlevel officer in Army G-2, to Governor Dewey,

General Marshall begged the governor to say nothing during the campaign about a certain piece of

very vital information which had become known to

the governor, it having been “leaked” to him by persons unknown and unauthorized to disclose it. The

information dealt with the fact that U.S. government authorities had been reading Japanese codes

and ciphers before the attack on Pearl Harbor. The

points which General Marshall wanted to convey

were not only that the “leaked” information was

true, but also that, much more important, (1) the

war was still in progress; (2) the Japanese were still

using certain of the pre-Pearl Harbor cryptosystems; and (3) the U.S. government was still reading

highly secret Japanese messages in those systems,

as well as highly secret messages of other enemy

governments. Therefore, it was absolutely vital that

Governor Dewey not use the top secret information

as political ammunition in his campaign.

After merely glancing over the first two paragraphs of the letter, Governor Dewey handed it

back to Colonel Clarke with the comment that he

did not wish to read any further, whereupon there

was nothing for Colonel Clarke to do but return

immediately to Washington. General Marshall then

made certain changes in the opening paragraphs of

the letter, and again Colonel Clarke hand-carried it

to the Governor, who then read the whole of it. In

my first lecture I said that I might later give further

extracts from Time’s account of this episode, but

there isn’t time. Instead, however, I’ve put the

whole account in Appendix I to the present lecture.

The Marshall-Dewey correspondence is so important in cryptologic history that I have deemed it

useful to put the whole of it in Appendix II.

The information disclosed during

the various official investigations of the

attack on Pearl

Harbor, so far

as concerns the

important

COMINT

achievements

of the Army

and the Navy

before and after that attack, was classified information of the very highest security level, and the disclosures were highly detrimental to our national

security. Much has been written about them since

Page 135

Fig. 102
the end of hostilities, and although all of that formerly top secret information is now in the public

domain, fortunately very few details of technical

significance or value can be found therein. Hints

and even blunt statements about the great role

played by COMINT in U.S. military, naval, and air

operations are found in books and articles published by U.S. government officials and American

officers, as well as by officers of the beaten

Japanese, German, and Italian armed forces. In the

interests of brevity, I will cite only a few examples.5

As regards disclosures by U.S. government officials and officers, I can begin with those of the late

Mr. Cordell Hull, who was secretary of state at the

time of the Pearl Harbor attack. In his memoirs are

many references (over a dozen) to the contents of

intercepted and solved Japanese Foreign Office

messages.6 The late Mr. Henry L. Stimson, secretary of war at that time, makes clear references in

his autobiography to COMINT successes and our

failure to use them prior to the attack.7 Dr. Herbert

Feis, who was Mr. Hull’s advisor on international

economic affairs from 1937 to 1943, and who from

1944 to 1946 was Mr. Stimson’s Special Consultant,

has a good deal to say about the role played by

“Magic” in a book written as a member of the

Institute for Advanced Study, at Princeton8

Admiral Kimmel, one of the two commanders in

Hawaii at the time of the attack, in defending himself in his book, cites many “Magic” messages.9 And

Major General Sherman Miles, head of G-2 at the

time of the attack, has much to say about “Magic” in

an article published in 1948.10 As regards disclosures by former enemy officers, the following are of

particular interest because they concern the Battle

of Midway, which is considered the one that turned

the tide of war in the Pacific from a possible

Japanese victory to one of ignominious defeat:

If Admiral Yamamoto and his staff were

vaguely disturbed by the persistent bad

weather and by lack of information concerning the doings of the enemy, they

would have been truly dismayed had they

known the actual enemy situation. Postwar American accounts make it clear that

the United States Pacific Fleet knew of the

Japanese plan to invade Midway even

before our forces had sortied from home

waters. As a result of some amazing

achievements by American intelligence,

the enemy had succeeded in breaking the

principal code then in use by the Japanese

Navy. In this way the enemy was able to

learn of our intentions almost as quickly as

we had determined them ourselves.

* * * * * *

The distinguished American Naval historian, Professor Samuel E. Morison, characterized the victory of United States forces

at Midway as “a victory of intelligence.” In

this judgment the author fully concurs, for

it is beyond the slightest possibility of

doubt that the advance discovery of the

Japanese plan to attack was the foremost

single and immediate cause of Japan’s

defeat.

Viewed from the Japanese side, this success of the enemy’s intelligence translates

itself into a failure on our part – a failure

to take adequate precautions for guarding

the secrecy of our plans. Had the secret of

our intent to invade Midway been concealed with the same thoroughness as the

plan to attack Pearl Harbor, the outcome

of this battle might well have been different. But it was a victory of American intelligence in a much broader sense than just

this. Equally as important as the positive

achievements of the enemy’s intelligence

on this occasion was the negatively bad

and ineffective functioning of Japanese

intelligence.11

It is the second extract above which is of special

interest to us at the moment, and, in particular, the

portion that refers to “the negatively bad and ineffective functioning of Japanese intelligence.” The

Page 136
author is, I think, a bit too severe on the Japanese

intelligence organization. I say this because their

cryptanalysts were up against much more 

sophisticated cryptosystems than they dreamt of, or

were qualified to solve. In fact, even if they had

been extremely adept in cryptanalysis, it would

have been of no avail – U.S. high-level communications were protected by cryptosystems of very great

security.

This brings us to a phase of cryptology that is of

highest importance – the phase that deals with

communications security, or COMSEC, and I shall

confine myself largely to its development and historical background in our armed forces. The background is a very broad one because it should

include the background of the developments of

each of the three components of COMSEC, viz, (1)

cryptosecurity, (2) transmission security, and (3)

physical security of cryptomaterials. But since time

is limited and because I think you would be more

interested in the phases pertaining to cryptosecurity, I will omit further references to the other two

components or to the history of their development.

And even in limiting the data to cryptosecurity, I

will have opportunity only to give some of the highlights of the development of the items that comprise our present cryptomaterials, omitting comments on the history of the development and

improvement of our techniques, procedures, and

practices, all of which are extremely important.

I shall begin the story with a definition that you

will find in any good English dictionary, a definition

of the word “accident.” You will get the point of

what may seem to you right now to be merely

another of my frequent digressions from the main

theme, but if it be a digression I think you will nevertheless find it of interest. The word “accident” in

Webster’s Unabridged Dictionary is defined as follows:

1. Literally, a befalling;

a. An event that takes place without one’s

foresight or expectation; an undesigned,

sudden, and unexpected event.

b. Hence, often, an undesigned and

unforeseen occurrence of an afflictive or

unfortunate character; a mishap, resulting

in injury to a person or damage to a thing;

a casualty; as, to die by an accident.

There are further definitions of the word, but

what I’ve given is sufficient for our purposes. 

But why define the word? What has it to do with

COMSEC?

During our participation in World War II, the

president of the United States, accompanied by

many of his highest-level military, naval, and civilian assistants, journeyed several times half way

around the world. He and they journeyed in safety;

neither he nor they met with an “accident.” Here’s a

picture taken at the Casablanca Conference in

January 1943 (fig. 103). Imagine the disaster, it

would have been if the plane carrying this distinguished group had been shot down and lost in the

Atlantic or the Mediterranean. On the other hand,

in April 1943 Admiral Isoroku Yamamoto,

Commander in Chief of the Combined Fleet of the

Fig. 103

Page 137
Japanese Imperial Navy, started out on what was to

be just an ordinary inspection trip but turned out to

be a one-way trip for him. Here’s a good picture of

the admiral (fig. 104), who was the architect of the

attack on Pearl Harbor. His death was announced

in an official Japanese Navy communique stating

that the admiral “had met a glorious end while

directing operations in a naval engagement against

superior enemy forces.” But we know that this 

was simply not true; Admiral Yamamoto “met with

an accident.” Some bright person – I think it was

the late Jimmy Walker, when mayor of New York

City – has said that “accidents don’t just happen –

they are brought about.” Jimmy Walker’s comment

was true in this case at least; Admiral Yamamoto

did not die by accident; he died because our navy

knew the schedule of his trip down to the very last

detail so that it was possible to set up an ambush

with high degree of success. Here is the story as told

in an interesting manner by Fleet Admiral William

F. Halsey, USN, in his book entitled Admiral

Halsey’s Story.

12

I returned to Noumea in time to sit in on

an operation that was smaller but

extremely gratifying. The Navy’s code

experts had hit a jackpot; they had discovered that Admiral Isoroku Yamamoto, the

Commander-in-Chief of the Imperial

Japanese Navy, was about to visit the

Solomons. In fact, he was due to arrive at

Ballale Island, just south of Bougainville,

precisely at 0945 on April 18. Yamamoto,

who had conceived and proposed the Pearl

Harbor attack, had also been widely quoted as saying that he was ftlooking forward

to dictating peace in the White House at

Washington.” I believe that this statement

was subsequently proved a canard, but we

accepted its authenticity then, and it was

an additional reason for his being No.3 on

my private list of public enemies, closely

trailing Hirohito and Tojo.

Eighteen P-38’s of the Army’s 339th

Fighter Squadron, based at Henderson

Field, were assigned to make the interception over Buin, 35 miles short of Ballale.

Yamamoto’s plane, a Betty, accompanied

by another Betty and covered by six Zekes,

hove in sight exactly on schedule and Lt.

Col. Thomas G. Lamphier, Jr., dove on it

and shot it down in flames. The other Betty

was also shot down for good measure, plus

one of the Zekes. . . We bottled up the

story, of course. One obvious reason was

that we didn’t want the Japs to know that

we had broken their code. . . .

Unfortunately, somebody took the story to

Australia, whence it leaked into the

papers, and no doubt eventually into

Japan.... But the Japs evidently did not

realize the implication any more than the

tattletale; we continued to break their

codes.

But lest you get the impression that enemy

intelligence agencies had no success at all with

secret communications of U.S. armed forces, let me

Page 138

Fig. 104
tell you that they did have some success and, in certain instances, very significant success. There is not

time to go into this somewhat disillusioning statement, but I can say that as a general rule the successes were attributable not to technical weakness

in U.S. cryptosystems, but to their improper use in

the case of certain low-level ones, by unskilled and

improperly or insufficiently trained cryptographic

clerks. I may as well tell you right now that this

weakness in cryptocommunications has been true

for a great many years, for centuries as a matter of

fact, because as long ago as 1605 Francis Bacon,

who wrote the first treatise in English on cryptology, made the following comment:13

This Arte of Cypheringe, hath for Relative,

an Art of Discypheringe; by supposition

unprofitable; but, as things, are of great

use. For suppose that Cyphars were well

managed, there bee Multitudes of them

which exclude the Discypherer. But in

regarde of the rawnesse and unskillfulness

of the handes, through which they passe,

the greatest Matters, are many times carryed in the weakest Cyphars.

When electrical, particularly radio, transmission entered into the picture, additional hazards to

communications security had to be taken into

account, but many commanders failed to realize

how much valuable intelligence can be obtained

merely from a study of the procedures used in the

transmission of messages as well as from a study of

the direction and flow of radio traffic, the call signs

of the transmitting and receiving stations, etc., all

without solving the communications even if they

were in cryptic form. Following are two paragraphs

extracted from a document entitled German

Operational Intelligence, published in April 1946

by the German Military Document Section, a

Combined British, Canadian, and U.S. Staff:

Signal intelligence (i.e., communication

intelligence or COMINT) was a chief

source of information in the German

Army. In the eastern theater, where there

was offensive warfare primarily, the signal

intelligence service was well-organized

with well-defined purposes, efficient personnel, and adequate equipment. In the

course of the campaign, it was reorganized

to exploit to the fullest the success already

experienced, and, by 1943, there existed a

complete and smoothly functioning

machine sufficient to meet all demands.

(p. 8.)

* * * * * * *

Most of their signal intercept success came

from low-echelon traffic. Armored and

artillery radio nets passing operational

traffic were followed closely and were one

of the chief sources of signal intelligence.

Artillery radio nets were given first coverage priority. Apart from messages intercepted in code or in clear, signal procedure, peculiarities of transmitting, and

characteristics of Allied radio operators

provided enormous assistance in helping

to evaluate signal information. The

Germans noticed that call signs were often

the same for a unit over long periods and

that even frequencies remained

unchanged for weeks at a time. (p. 8.)

A great many examples of intercepted messages

of tactical content are cited in the aforementioned

document, which is replete with information of

deep interest, although the document was originally issued with the lowest security classification then

in use (U.S. “Restricted”; British-Canadian “FOR

OFFICIAL USE ONLY”). I wish there were time to

quote at greater length from this useful brochure.

Coming directly now to the history of the development of our cryptomaterials themselves, I hardly

need reiterate what was pointed out in previous lectures as to the profound effect of the advances in

the science and art of electrical communications in

the twentieth century. Those advances had a direct

effect upon military communications and an indiPage 139
rect effect upon military cryptology. Hand-operated

ciphers and, of course, code books became almost

obsolete because the need for greater and greater

speed of cryptographic operations became obvious

in order to match as much as possible the very 

great increase in the speed of communications

brought about by inventions and improvements in

electric wire and radiotelegraphy. The need for

cryptographic apparatus and machines thus very

soon became quite obvious, but it took quite some

time to satisfy that need in a manner that could be

considered to give adequate security for military

communications.

The history of the invention and development of

cryptographic devices, machines, and associated

apparatus and material is long and interesting. Let

us begin with a resumé of the earliest items ofimportance in that history.

Until the advent of electronic cipher machines,

most cryptographic apparatus and devices were

built upon or around concentric circular rotating

members such as cipher wheels, cipher disks, etc. A

very early, perhaps the earliest, picture of such a

device appears in a treatise by an Italian cryptologist named Alberti, whose Trattati in Cifra was

written in Rome about 1470. It is the oldest tract on

cryptography the world now possesses. Here’s a

photo of Alberti’s disk (fig. 105), but I won’t take the

time to explain it except to say that the digits 1, 2, 3,

4 were used to encipher code groups and to call

your attention to the fact that the letters of the

cipher or revolving alphabet were in mixed order.

In Porta’s book, first published in 1563 in Naples,

there appear several cipher disks; in the copy which

was given me as a gift by Colonel Fabyan, they are

still in working condition. Here is a picture of one of

them (fig. 106). In this version the device uses symbols as cipher characters. And apparently nobody

thought up anything much better for a long, long

time. It seems, in fact, that not only did no one

think up anything new or even some improvements

on the original Alberti or Porta disks, but those who

did any thinking at all on the subject merely

“invented” or “reinvented” the same thing again,

and that happened repeatedly in successive generations. For instance, in Lecture No. IV of this series

you were shown a picture of the cipher disk “invented” by Major Albert Myer, the first Chief Signal

Officer of the U.S. Army, who obtained a patent on

his invention in 1865. Here’s a picture of the patented disk (fig. 107) and the explanation of the invention (fig. 108). You may also remember that signalmen of the Confederate Signal Corps mechanized

the old Vigenère Square and put it out in the form

of a cylinder (see figures 65 and 66 of Lecture No.

Page 140

Fig. 105

Fig. 106
IV). The cipher disk used by the Signal Corps of the

U.S. Army from 1910 to 1920, that is, during the

period including our participation as a belligerent

in World War I, was nothing but a white celluloid

variation of the original Alberti parchment disk of

the vintage of 1470 (except that it was even simpler

than its progenitor, because in the latter the cipher

alphabets produced were mixed alphabets whereas

in the Signal Corps disk, the cipher alphabets are

simple reversed standard sequences (fig. 109). We

all know that it generally takes a pretty long time to

get a patent through the U.S. Patent Office, but the

ancient device was patented in 1924 by S.H.

Huntington (fig. 110): here you can see a great

improvement over the Signal Corps version – a

blank is added to both sequences so that the space

between words could be enciphered. Indication of

word space, as you have learned, is a fatal weakness

if seen in the cipher text; in the Huntington device

the spaces between words would be enciphered, but

the cipher text would have space signs, although

they would not correspond to the actual spaces

between words in the plain text. In the Huntington

device, the space signs in the cipher text would be a

bit misleading but not to an experienced cryptanalyst, who would soon realize that they do not actually represent “word space” in the plain text.

It is interesting to note that in 1936, during the

days when the German National Socialists were

banned as an organization in Austria, the Nazis

used this variation of the old disk – it had ten digits

on both the outer and the inner sequences for enciphering digits (fig. 111).

The first significant improvement on the old

cipher disk was that made by Sir Charles

Wheatstone in 1867, when he invented a cipher

device which he called The Cryptograph. He

described it in a volume entitled The Scientific

Papers of Sir Charles Wheatstone, published in

1879 by the Physical Society of London. Here is a

picture of the Wheatstone device in my private collection (fig. 112). What Sir Charles did was to make

the outer circle of letters (for the plain text) comprise the twenty-six letters of the alphabet, plus one

additional character to represent “space.” The inner

circle, for cipher equivalents, contains only the

twenty-six letters of the alphabet, which can be disarranged in a mixed sequence. Two hands, like the

hour and minute hands of a clock, are provided,

and they are under control of a differential gear

mechanism, so that when the long or “minute

hand” is advanced to make a complete circuit of the

letters on the outer circle, the short or “hour hand”

advances one space or segment on the inner circle.

In figure 112, for example, the plaintext letter G is

represented by the cipher letter A, that is, Gp = Ac.

If the long hand is now advanced in a clockwise

direction for one revolution, Gp will be represented

no longer by Ac but by Gc” the letter immediately to

the right of Ac on the inner circle. In encipherment

the long hand is always moved in the same direction (clockwise, for example), and its aperture is

placed successively over the letters on the outer circle according to the successive letters of the plaintext message, the cipher equivalents being recorded

by hand to correspond with the letters to which the

short hand points on each encipherment. In this

way, identical letters of the plain text will be represented by different and varying letters in the cipher

text, depending upon how many revolutions of the

long hand intervene between the first and subsequent appearances of the same plaintext letter.

Thus, with the alphabets shown in figure 112, and

with the initial setting Gp =Ac, the word “reference”

would be represented in cipher as follows:

REFERENCE

XZZZBGQAM,

in which it will be seen that repeated letters in the

plain text are represented by different letters in the

cipher text. Correspondents must naturally agree

upon the mixed alphabet used in the inner circle

and the initial positions of the two hands at the

beginning of the encipherment of a message. In

decipherment, the operator moves the long hand

again clockwise, until the hour hand points to the

cipher letter in the plaintext letter that is seen

through the aperture at the end of the long hand on 

Page 141
Page 142

Fig. 107
Page 143

Fig. 108
the outer circle. Thus, in the case of the example

given above, the cipher letters XZAABGQAM will

be found to represent the word REFERENCE.

During World War I, sometime in 1917, the

British army resuscitated Wheatstone’s cryptograph and improved it both mechanically and cryptographically. Here’s a picture of the device (fig.

113), in which it will be seen that there are now no

longer the “minute” and “hour” hands but a single

hand with an opening or window that simultaneously disclosed both the plain and the cipher letters.

When the single hand is turned, the inner circle of

segments, which are made of a substance upon

which letters may be written in pencil or in ink is

advanced eccentrically and against a similarly

made outer circle of segments. In this improvement

on the original Wheatstone device, both sequences

of letters are now mixed sequences. Making the

outer circle also a mixed sequence added a considerable degree of security to the cipher. When it was

proposed that all the Allied armies use this device

for field cryptocommunications and its security had

been approved by British, French, and American

cryptologists (both at GHQ-AEF and at

Page 144

Fig. 109

Fig. 110

Fig. 111

Fig. 112
Washington), an opportunity to agree or disagree

with the assessment of these cryptologists was

given me while still at Riverbank. I was able to show

that the modified Wheatstone cryptograph was still

insufficiently secure for military purposes, and the

devices, thousands of which had been manufactured and issued, were withdrawn. If you are interested in the method of solution I used, you will find

it in Riverbank Publication No. 20, entitled Several

Machine Ciphers and Methods for their Solution

(1918). A better method of solution was devised by

me about 1923.

Some years later, and almost by sheer good fortune, I learned that a cipher machine was in the

museum of a small town in Connecticut named

Hamden. I was interested and wrote to the curator

of the museum, requesting that he lend the device

for a short period to me as principal cryptanalyst of

the War Department. Imagine my astonishment

and pleasure when I unpacked the box upon its

receipt and found a device, beautifully made and

encased in a fine mahogany case, with its inventor’s

name, Decius Wadsworth, and the date, 1817,

engraved on the face of the machine, which was

nothing but another version of the Wheatstone

Cryptograph. Here’s a picture of it (fig. 114). There

are good reasons to believe that the model was

made by Eli Whitney. Mechanically, it was similar

to the British modification, except that the outer

sequence had thirty-three characters, the inner,

twenty-six, so that the differential gear instead of

operating on the ratio of 27 to 26 was now on the

ratio 33 to 26. Thus, Colonel Decius Wadsworth,

Page 145

Fig. 113

Fig. 114 Fig. 115

Fig. 116
who was then the first Chief of Ordnance of the U.S.

Army, had anticipated Wheatstone by over sixty

years in this invention. He also anticipated the

British army cryptologists of World War I by a

whole century in their modification of

Wheatstone’s original, because in the Wadsworth

device, too, there was only one hand and both

alphabets could be made mixed sequences. This is

very clearly shown in figure 115 as regards the outer

sequence, and I believe the inner one could also be

disarranged, but the picture does not clearly show

this to be the case, so that I am not sure as to this

point. I returned the device a good many years ago,

and it is now on display in the Eli Whitney Room

ofthe New Haven Historical Society’s Museum.

The next device I bring to your attention is

shown in figure 116, a device invented by a French

army reservist, Commandant Bazeries, who for

some ten years valiantly but unsuccessfully tried to

get the French army to adopt it. He included a

description of his device, which he called his

“Cryptographe Cylindrique” or “cylindrical cryptograph,” in a book published in 1901 in Paris.14 He

had, however, previously described his device in an

article entitled “Cryptographe à 20 Rondelles -

alphabets (25 lettres par alphabet),” published in

1891.15 In this device there is a central shaft on

which can be mounted twenty numbered disks on

the peripheries of which are differently mixed

alphabets of twenty-five letters each. The disks can

be assembled in some prearranged or key sequence

on the shaft, from left to right, but they can be

revolved thereon and then locked into position on

the shaft by pushing in the locking disk at the

extreme left. The first twenty letters of the plain text

of a message are first aligned, as seen in figure 116

(JE SUIS INDÉCHIFFRABLE = “I am indecipherable”); the disks are then locked into position so

that the whole assembly can be turned; and as

cipher text one may select anyone of the other

twenty-four rows of letters, which are recorded

then by hand on paper. Then the next twenty plaintext letters are aligned, one of the other twenty-four

rows of letters selected and recorded, etc. To decipher a message, the disks having been assembled

on the shaft in accordance with the prearranged or

key sequence, one takes the first twenty cipher letters, aligns and then locks them into position, and

then turns the whole cylinder, searching for a row

of letters which form intelligible text. There will be

one and only one such row, and the plaintext letters

are recorded. Then the next twenty letters of cipher

are aligned, etc.

Another French cryptologist, the Marquis de

Viaris, soon showed how messages prepared by

means of the Bazeries cylindrical cipher could be

solved.16 Maybe that is why Bazeries wasn’t too successful in his attempt to get the French army to

adopt his device. But in the United States there

were apparently none who encountered either what

Bazeries or de Viaris wrote on the subject. Captain

Parker Hitt, U.S. Army, whom I have mentioned in

a previous lecture, in 1915 invented a device based

upon the Bazeries principle but not in the form of

disks mounted upon a central shaft. Instead of

disks, Hitt’s device used sliding strips. Here is a picture of his very first model (fig. 117), which he presented to me sometime in 1923 or 1924. But I first

learned about his device sometime in 1917 while

still at Riverbank and solved one challenge message

put up by Mrs. Hitt, a Riverbank guest for a day. In

meeting the challenge successfully (which brought

a box of chocolates for Mrs. Friedman from Mrs.

Hitt), I didn’t use anything like what I could or

might have learned from de Viaris, because at that

time I hadn’t yet come across the de Viaris book. I

solved the message by guessing the key Mrs. Hitt

employed to arrange her strip alphabets. She wasn’t

wise to the quirks of inexperienced cryptographic

clerks: she used RIVERBANK LABORATORIES as

the key, just as I suspected she would. The device

she brought with her was an improved model: the

alphabets were on paper strips, and the latter were

glued to strips of wood, as seen in figure 118.

Captain Hitt brought his device to the attention

of the then Major Mauborgne, whom I have also

mentioned in a previous lecture and who was then

on duty in the Office of the Chief Signal Officer in

Washington. There is some question as to whether

Page 146
it was Hitt who first brought his device to

Mauborgne’s attention; Mauborgne later told me

that he had independently conceived the invention

and, moreover, had made a model using disks

instead of strips. I have that model, a present from

General Mauborgne many years later. It is made of

very heavy brass disks on the peripheries of which

he had engraved the letters of his own specially

devised alphabets. In 1919, after my return to

Riverbank from my service in the AEF, Mauborgne

sent Riverbank the beginnings (the first twenty-five

letters) of a set of twenty-five messages enciphered

by his device and alphabets. He also sent the same

data to Major Yardley, in G-2. Nobody ever solved

the messages, even after a good deal of work and

even after Mauborgne told us that two consecutive

words in one of the challenge messages were the

words “are you.” Many years later I found the reason for our complete lack of success, when I came

across the plain texts of those messages in a dusty

old file in one of the rooms occupied in the old

Munitions Building by the Office of the Chief Signal

Officer. Here is a picture of the beginnings of the

first six messages (fig. 119). Mauborgne, when I

chided him on the unfairness of his challenge messages, told me that he had not prepared them himself – he had an underling (Major Fowler was his

name, I still remember it!) prepare them. In our

struggles to solve the challenge messages, we had

assumed they would contain the usual sorts of

words found as initial words of military messages.

It was the complete failure by Riverbank and G-2 to

solve the challenge messages that induced

Page 147

Fig. 117

Fig. 118
Mauborgne to go ahead with the development of

his device. It culminated in what became known as

Cipher Device, Type M-94. Here is a picture of it

(fig. 120). That device was standardized and used

for at least ten years in the United States by the

Army, the Navy, the Marine Corps, the Coast

Guard, the intelligence operations of the Treasury

Department, and perhaps by other agencies.

In 1922, a wartime colleague, the late Captain

John M. Manly (professor and head of the

Department of English at the University of

Chicago) brought to my attention a photostat of two

pages of a holographic manuscript in the large collection of Jefferson Papers in the Library of

Congress. It described his invention entitled “The

Wheel Cypher,” and figure 121 is a picture of the

second page showing Jefferson’s basis for calculating the number of permutations afforded by the set

of thirty-six wheels of his device. He didn’t attempt

to make the multiplication; he didn’t have an electronic digital computer – for the total number is

astronomical in size. Jefferson anticipated Bazeries

by over a century, and the Hitt-Mauborgne combination by almost a century and a half.

It soon became apparent to both army and navy

cryptologists that a great increase in cryptosecurity

would be obtained if the alphabets of the M-94

device could be made variant instead of invariant.

There began efforts in both services to develop a

practical instrument based upon this principle. I

won’t take time to show all these developments but

only the final form of the one adopted by the Army,

Strip Cipher Device Type, M-138A (fig. 122). This

form used an aluminum base into which channels

with overhanging edges were cut to hold cardboard

strips of alphabets which could be slid easily within

the channels. It may be of interest to you to learn

that after I had given up in my attempts to find a

Page 148

Fig. 120

Fig. 119

Fig. 121
firm that would or could make such aluminum

grooved devices in quantity, Mrs. Friedman, by

womanly wiles and cajolery on behalf of her own

group in the Coast Guard, succeeded in inducing or

enticing one firm to make them for her. And that’s

how the first models of strip cipher devices made of

aluminum by the extrusion process came about,

and how the U.S. Army, by administrative cooperation on an interservice level and technical cooperation on a marital level, found it practical to develop

and produce in quantity its Strip Cipher Device,

Type M-138A. This was used from 1935 to 1941 or

1942 by the Army, the Navy, the Marine Corps, the

Coast Guard, et al., including the Treasury and

State Departments. It was used as a back-up system

even after the armed services as well as the

Department of State began employing much better

and more sophisticated cipher machines of high

speed and security.

Thus far we have been dealing with cipher

devices of the so-called “hand-operated” type. None

of them can readily be considered as being

“machines,” that is, apparatus employing mechanically driven members upon which alphabetic

sequences can be mounted so that constantly

changing sequences of cipher alphabets are produced. We come now to types of apparatus that can

be called machines, and one such machine is shown

in figure 123. It is called the Kryha machine, after

the name of its German inventor, who unfortunately committed suicide a few years ago, perhaps

because the last model of his improved machine

failed to impress professional cryptologists. The

Kryha has a fixed semicircle of letters against which

is juxtaposed a rotatable circle of letters. Both

sequences of letters can be made mixed alphabets

(the segments are removable and interchangeable

on each sequence). The handle at the right serves to

wind a rather powerful steel clock spring that drives

the rotatable platform on which the letters of the

inner circle are mounted. In figure 124 can be seen

something of the inner mechanism. The large wheel

at the right has segments that are open or closed,

depending upon the “setting” or key. This wheel

controls the angular displacement or “stepping” of

the circular rotatable platform. The initial juxtaposition of the inner or movable alphabet against the 

Page 149

Fig. 122
Page 150

Fig. 124

Fig. 123
outer or fixed one, as well as the composition of

these alphabets, is governed by some key or other

prearrangement. The cipher equivalents must be

recorded by hand. After each encipherment, the

button you saw in the center of the panel in figure

123 is pushed down, the inner wheel is advanced 1,

2, 3, 4 . . . steps, depending on the key, and the next

letter is enciphered, etc. The pictures I’ve shown

you apply to the latest model of the Kryha; as

regards the first model, which came on the market

sometime in the 1920s, a German mathematician

produced an impressive brochure showing how

many different permutations and combinations the

machine afforded. Here’s a picture of a couple of

pages of his dissertation (fig. 125), but even in those

days professional cryptanalysts were not too

impressed by calculations of this sort. With modern

electronic computers such calculations have

become even less significant.

Let us now proceed with some more complex

and more secure machines. In this next illustration

(fig. 126), you see a machine that represents a

rather marked improvement by a Swedish cryptographic firm upon the ones shown thus far. It is a

mechanico-electrical machine designated as

Cryptographe B-21. Here for the first time you see a

cryptographic machine provided with a keyboard

similar to that on an ordinary typewriter.

Depressing a key on this keyboard causes a

lamp to light under one of the letters on the

indicating bank above the keyboard. At the top of

this machine can be seen four wheels in front of two

rear wheels. The four front wheels are the rotating

elements that drive the two rear wheels; the latter

are electrical commutators that serve as connection-changers to change the circuits between the

keys of the keyboard and the lamps of the indicating board. There isn’t time to discuss in detail the

internal works that control the rotating elements

and ciphering wheels, of which you’ll see a glimpse

later, but I must show you the next step in the

improvement of such apparatus, which made it

possible to eliminate the really tedious job of

recording, by hand on paper, the results of operation. This was done by means of associating a typePage 151

Fig. 125

Fig. 126

Fig. 127
writer with the cryptocomponent. Here is a picture

(fig. 127) that shows the assembly – the B-21 connected to a Remington electric typewriter, modified

to be actuated by impulses from the cryptomachine.

Of course, it was natural that the next step would be

to make the recording mechanism an integral part

of the cryptomachine. This you can see in the next

picture (fig. 128a), in which the four rotating members referred to in connection with figure 126 and

which control the two commutators also mentioned

in connection with that figure are seen. The slidebar mechanism, in figure 128b, at the right, is called

the “cage” or “barrel,” and it controls the displacements of the printing wheel, causing the proper letter to be printed upon the moving tape seen at the

front of the machine.

Now we come to some very important new

types of electric cipher machines first conceived

and developed in Europe but very soon thereafter,

and probably independently, also in the United

States. In the cryptocomponent of these machines,

the electrical paths between the elements representing the plaintext characters and those representing their cipher equivalents are constantly varied by multiple connection-changers with the cryptocomponent. In early European models of this

type of machine, the connection-changers consisted of a frame upon which insulated wires were

mounted to connect in an arbitrary manner a series

of contacts on one side of the frame to a similar

number of contacts on the other side of the frame.

This frame was slid between two fixed contactbearing members, one on each side of the frame. By

sliding the frame between the two fixed members,

the paths between the opposite contacts on the latter could be varied as a whole set with a single

movement of the sliding frame. A connectionchanger of this sort is shown in schematic form in

figure 129a, where the sliding member 10 slides

between fixed members 11 and 12, thus changing

the electrical paths between the keyboard and the

printing mechanism. The connection-changer 10 is

moved to the left or right 1,2,3, . . . positions, as

determined by a cam mechanism. We won’t go into

this type of machine any further because it wasn’t

long before inventors saw the advantages of using,

instead of slideable connection-changers, mechanisms performing a similar function but of a rotatable nature that we now call “electric-rotors,” and

that rotate, usually step-by-step, between circular,

fixed, contact-bearing members called “stators.”

Rotors and stators of this type are shown in

schematic form in figure 129b, there being a lefthand stator labeled 1, three rotors labeled 2a, 2b,

2c, and a right-hand stator labeled 3. The connections leading away from stator 1 toward the left go

to the keys of the keyboard; those leading away

from rotor 3 toward the right go to the magnets of

the printer. About these elements we shall explain

some details presently.

Page 152

Fig. 128a

Fig. 128b
In Europe, the first machine using rotors and

stators was that developed by a German firm, the

Cipher-Machine Company of Berlin, and was

appropriately named the ENIGMA. Here’s a picture

of it, figure 129c, in which you see a keyboard, a set

of eight rotors juxtaposed in line, or, as we now generally say, “juxtaposed in cascade,” and a printer.

This machine was apparently too complicated for

practical usage and was superseded by a second

model, which also printed and was also unsuccessful. One of the difficulties with these two models

was that a multiple switch with many contacts to be

made simultaneously was required in order to

establish an operative encipher-decipher relationship, so that if in enciphering the letter Dp, for

example, the corresponding key on the keyboard is

depressed, and a cipher letter, say Fe, is printed;

then on deciphering the letter Fe, the corresponding key on the typewriter is depressed, and the

plaintext letter Dp will be printed. In this machine

this could be done only by making the current for

decipherment traverse exactly the same path

through the rotors and stators that it had traversed

in encipherment. This was the function of the multiple switch shown schematically in figure 129d, in

which a machine with only six characters (A to F) is

depicted. In the left-hand circuit diagram, Dp is

being enciphered and produces Fe; in the right

hand circuit diagram Fe produces Dp. But the

switching mechanisms 4 and 4’ in figure 129d make

things a bit complicated because they are within

one switching member that operates in one of two

positions, one for encipherment, the other for decipherment, and many contacts must be established

in one fell swoop, so to speak. I won’t go into further

details as to its construction because a clever inventor of that German firm came up with a new idea

which greatly simplified matters, in regard not only

to the cryptocomponent but also to the indicating

mechanism. We may quickly explain how the matter of simplifying the indicating mechanism was

accomplished, namely, by eliminating the printer

altogether and replacing it with a simple bank of

flashlight-type lamps. We’ll skip the third model of

the ENIGMA, which was only a slightly simpler version of the fourth model, which is shown in figure

130a. This one comprised a keyboard, a bank of

indicating lamps, and a set of rotors and stators, but

no printer.

In figure 130a is seen the machine with its coverplate down. At the front is the keyboard; above it,

the indicator board, consisting of twenty-six lamps

beneath glass disks upon which letters have been

inscribed. Above the indicator board are seen four

oval apertures with covers, through which letters

can be seen. To the right of each aperture can be

seen the peripheries of four metal scalloped wheels,

the first being unmarked but the next three being

labeled 1. A switch lever seen at the right can be set

to encipher, decipher, or neutral positions. In figure

Page 153

Fig. 129a

Fig. 129b

Fig. 129c
130b is seen the machine with the coverplate

removed, exposing the internal cryptocomponent.

Three rotors, labeled 4 in this figure, are seen, and

affixed to them are the scalloped metal rings, 

which are not labeled. A fourth scalloped ring,

labeled 11 in figure 130b, is affixed to another rotorlike member labeled 8 in that figure. This member

looks like an ordinary rotor in this picture but is

really a stator of special construction to be

described presently.

Perhaps it would be useful at this point to show

you what ENIGMA rotors look like and these can be

seen in figures 131a-c. In each of these rotors is a

circle of twenty-six equally spaced contact pins on

one face of the rotor (fig. 131a) and a circle of twenty-six equally spaced contact surfaces on the other

face (fig. 131b). Insulated wires connect the contact

pins on one face to the contact surfaces on the other

face, these connections being made in an arbitrary,

systematic, or unsystematic manner, depending on

certain circumstances into which we need not go.

When the rotors are juxtaposed as seen in figure

131c, the contact pins on one rotor are brought

against the contact surfaces on the adjacent rotor,

so that an electric current will traverse all three

rotors via a certain path. The large scalloped rings

are for setting the rotors in alignment manually

when they are juxtaposed and rotated to form a

portion of the key setting (see E*Z*R in figure 131c).

The toothed metal ring seen in figure 131a is associated with a cam mechanism so that a rotor will be

advanced one step when the preceding rotor has

made a sufficient number of steps to permit a cam

to fall into a notch in the ring. Sometimes a complete revolution will be necessary before this happens, depending on the initial keysetting. The first

rotor immediately to the left of the stator at the

extreme right in figure 131b, however, always

makes one step with each depression of the key on

the keyboard. The advance of the rotors is similar to

that of the wheels of a counter like that of the

odometer on your automobile.

We come now to the matter of simplifying the

cryptocomponent of the ENIGMA shown in figure

130b to eliminate the multiple switching mechanism shown in figure 129d, without much loss in

security (or so it would seem, at least). Let us see

how this simplification was accomplished in the

ENIGMA, by showing figure 129d, in connection

with the first ENIGMA model. For this purpose I

show you now figure 132, in which the encipherdecipher circuitry is clearly seen in a machine having, for illustrative purposes, only three rotors,

labeled 1, 2, 3, rotatable between two stators, the

one on the left labeled 4, that on the right labeled 5.

Stator 4 is fixed or nonrotatable in this model, and

it has twenty-six contacts on its left face, only two of

which are shown. These contacts are connected

fixedly to the keys of the keyboard and to the lamps

of the lampboard. Stator 5 is rotatable, but only

manually, and it has twenty-six contact surfaces on

its right face, only two of which are shown. But in

this stator the twenty-six contact surfaces are interconnected in pairs by thirteen insulated wires passing through the member. Thus, a current entering

one of the twenty-six contact surfaces on the right

face goes through the stator and returns to one of

the remaining twenty-five contact surfaces. For this

reason it is called a “reflector” and serves to return

a current that has come from one of the twenty-six

contacts on the fixed stator at the extreme right,

then through the rotors and into the reflector via

one path, returns through the rotors and back into

the stator via a different path, emerging at one of 

Page 154

Fig. 129d
the twenty-five other contacts on the left face of the

stator at the extreme right. This circuitry assures

that in a particular setting of the machine, if Yp =

Zc, for example, then Yp = Zc, that is, the cipher is

reciprocal. It also has as a consequence that no letter can be enciphered by itself, that is, Yp, for example, cannot be represented by Yc, no matter what

the setting of the cryptocomponent is; this is true of

all the other letters of the alphabet in regard to the

ENIGMA.

If you like, you may trace the path traversed by

the current in figure 132 in encipherment and decipherment, where Zp = Yc and Zp = Yc, but Zp cannot be represented by Zp, nor can Yp be represented by Yc. I have already told you briefly about how

the rotors are advanced. In the ENIGMA shown,

the total number of encipherments that can be

made before the key setting of the machine returns

to its original setting, as seen through the windows

I referred to a few moments ago when showing you

the first picture of the fourth model ENIGMA, is

16,900, viz, 263 – 262, and not 263, for technical

reasons I won’t go into now.

Power for the electrical circuits is provided by

small dry cells in the machine. This model enjoyed

a fair degree of financial success, but when Hitler

came into power further promotion and sales of the

ENIGMA were prohibited. Suffice it to say that it

became the basis for machines used by the German

Page 155

Fig. 130a

Fig. 130b

Fig. 131a Fig. 131b

Fig. 132

Fig. 131c
armed forces in World War II.

In the United States, in about 1910, a California

inventor named Edward H. Hebern (fig. 133) began

to develop cipher machines, but he was merely

traveling along roads that had this far led other

inventors nowhere. In about 1918 he struck out

along a new path in America. I don’t know whether

he independently conceived the idea of a machine

using an electric rotor or had in his research come

across patents covering very recently invented

European electrical cipher machines. At any rate,

Hebern’s first application for a patent covering a

rotor machine, which he called an “electric code,”

was filed on 31 March 1921, and a patent was issued

on 30 September 1924. Figure 134 shows the first

machine he had built. You will note that the cryptocomponent had but one rotor, and like the early

models of the ENIGMA, it was associated with a

printing mechanism, a typewriter operated electrically. Hebern’s cipher system was also similar in

nature with that of the first two ENIGMA models -

a full reversing switch was essential since the electric current had to traverse exactly the same path in

decipherment as it had in encipherment. I don’t

think he ever conceived the idea of using a reflector;

perhaps he was too late. At any rate, he never incorporated that idea in any of his machines. Moreover,

I don’t think he had any idea of the cryptologic

advantages and disadvantages of a cryptocomponent using a “single traverse” or “straight through”

system of rotors, as compared with one using a

“double traverse” or “twice through” system of

rotors with a reflector. But we won’t go into that

here, for it’s a pretty involved piece of business.

But Hebern’s rotors had a virtue not possessed

by those of the ENIGMA machines, and not incorporated in the rotors of the latter, namely, the

wirings of the rotors could be readily changed by

the user of the Hebern machine, a feature of great

importance in cryptosecurity (fig. 135). Hebern

interested our navy in his three-rotor model (fig.

136) and as a result of conferences with navy cryptanalysts he built the five-rotor model, which is seen

in figure 137. Another very important security feature I have thus far failed to mention about the

Hebern rotors was that they could be inserted in a

“right-side up” or in an “upside-down” position in

the machine, which could not be done with the

ENIGMA rotors. The navy liked the five-rotor

model, even though it was not a printing machine,

assuming properly that this could be added later

on. Therefore, the navy placed a purchase order for

two such machines on 30 July 1921 and was considering purchasing a rather large number of them

later. Lieutenant Strubel, then chief of the Navy’s

Code and Signal Section of the Office of Naval

Communications but now a retired vice admiral,

asked me to study the machine for its cryptosecurity. The Navy had but two machines, neither of

which could be made available, so I induced the

Chief Signal Officer to buy a couple of them for

Army study. The order was placed on 7 October

1924. The rotor wirings of the Army’s machines

were altogether different from those of the Navy, a

fact I discovered simply by asking Strubel to encipher a few letters on his machine, using settings I

specified. After some study I reported that in my

opinion the security of the machine was not as great

as the Navy thought. The result was a challenge,

which I accepted. The Navy gave me ten messages 

Page 156

Fig. 133
Page 157

Fig. 134

Fig. 135 Fig. 136
put up on its machine, and I was successful in solving them. There isn’t time to go into the methods

used, but if you are interested you can find them

described in my brochure entitled Analysis of a

Mechanico-Electrical Cryptograph, Part I (1934),

Part II (1935).

Hebern built several more models for Navy, and

these had printing mechanisms associated with

them, but Navy dropped negotiations with Hebern

when it became obvious that he was not competent

to build what Navy wanted and needed. Navy then

established its own cryptographic research and

development unit at what is now known as the

Naval Weapons Plant in Washington. Army developed at the Signal Corps Laboratories at Fort

Monmouth a machine known as Converter M-134,

and here’s an illustration (fig. 138) showing what it

looked like. Army and Navy went separate ways in

such work for a number of years, but finally, in 1938

or 1939, close collaborating brought as a result an

excellent machine that was developed and produced in quantity by the Teletype Corporation in

Chicago. This machine was distributed and used

very successfully by all our armed forces from 1940

to the end of World War II and for some years

thereafter. In accordance with Navy nomenclature,

it was designated as the ECM Mark II, ECM standing for “electric cipher machine”; in the Army it was

designated as the SIGABA, in accordance with a

nomenclature in which items of Signal Corps cryptographic material were then given short titles with

the initial trigraph SIG.

The ECM-SIGABA is a rather large machine

requiring a considerable amount of electric power

and much too heavy to be carried about by a signal

operator performing field service. It was safeguarded with extreme care and under strictest security

regulations during the whole period of World War

II operations. None of our allies was permitted even

to see the machine, let alone have it. The British had

their own electric cipher machine, which they called

TYPEX. In order to facilitate intercommunication

between U.S. and British forces, adaptors were

developed so that messages could be exchanged in

cipher between American and British units. This

system of intercommunication worked satisfactorily and securely.

Certain improvements in the method of usage

and the development of special components, to be

associated with the ECM-SIGABA for automatic

decipherment by perforated tapes, were introduced

during the wartime employment of these machines.

But the ECM-SIGABA as originally developed and

produced became obsolete some years after the

close of hostilities when newer and better machines

developed by NSA cryptologists and engineers

replaced them, but not because there were ever any

indications that messages enciphered on the

Page 158

Fig. 137

Fig. 138
machine had been deciphered by the enemy. As a

matter of historical fact, it may be stated that all

enemy efforts to solve such messages were fruitless,

and it is also a fact that no machines were ever captured by the enemy; nor were there ever any suspicions that a machine had been exposed to enemy

inspection at any time. Once and only once were

there any apprehensions in this regard, when

through a careless disregard of specific instructions, a truck and an attached trailer in which this

machine and associated material were housed were

stolen during the night when parked in front of the

headquarters of the 28th Division during the Battle

of the Bulge. A great search was instituted, during

the course of which a river was diverted, and the

trailer, with all its contents intact, was found resting

on the former bed of the diverted stream. The

episode terminated in court-martial proceedings,

and there were no more incidents of this sort. Let

me add that such apprehensions as were entertained at the time of this temporary loss of custody

of the machine were based not upon the possibility

that its usefulness was at an end but upon the fear

that the Germans would make “Chinese copies” of it

and thus be in a position to turn our very valuable

weapon against us.

About five years before the SIGABA was put

into service, the Army’s need for a small cipher

machine for field use became obvious. The strip

cipher system was not suitable for this purpose, nor

was the Army’s first keyboard-operated electrical

rotor machine, Converter M-134, suitable, for reasons already indicated in connection with the

SIGABA. The sum of $2,000 was allotted by the

Army to the Chief Signal Officer for the development of a cipher machine small enough to be suitable for field usage but also affording adequate

security. The funds were naturally turned over to

the Signal Corps Laboratories (SCL) at Fort

Monmouth, New Jersey, for this development. The

military director of the laboratories, spurning all

proffered technical guidance or assistance from the

Signal Intelligence Service (SIS) and deciding that

his staff had sufficient know-how without outside

assistance, developed a machine that required no

electricity, being allmechanical. On its completion

the model was sent to the Signal Intelligence

Service for a cryptosecurity test. Two short messages were enciphered by the Chief of the SIS, using

settings of his own selection. He then handed the

messages and the model over to me as technical

director, and I turned them over to two of my assistants. The reason for turning over the model with

the messages was that it must be assumed that

under field conditions machines will be captured.

One of the two test messages was solved in about

twenty minutes; the other took longer – thirty-five

minutes. This test brought an ignominious end to

the SCL development, brought about by the failure

on the part of the military director of the SCL to recognize that cryptographic invention must be guided

by technically qualified cryptanalytic personnel.

Unfortunately, all the available funds had been

expended on this unsuccessful attempt; none was

left for a fresh start on a development with technical guidance from the SIS.

It was about this

time that a small

mechanical machine

which had been

developed and produced in quantity by

a Swedish engineer

in Stockholm named

Hagelin (fig. 139)

was brought to the

attention of the Chief

Signal Officer (CSO)

of the U.S. Army by a

representative of the

Hagelin firm. The

SIS was asked to

look into it, and as technical director, I turned in an

unfavorable report on the machine for the reason

that although its cryptosecurity was theoretically

quite good, it had a low degree of cryptosecurity if

improperly used – and practical experience had

taught me that improper use could be expected to

occur with sufficient frequency to jeopardize the

security of all messages enciphered by the same setPage 159

Fig. 139
ting of the machine, whether correctly enciphered

or not. This was because the Hagelin machine operates on what is termed the key-generator principle,

so that when two or more messages are enciphered

by the same key stream or portions thereof, solution of those messages is a relatively simple matter.

Such solution permits recovery of the settings of the

keying elements so that the whole stream can be

produced and used to solve messages that have

been correctly enciphered by the same key settings,

thus making a whole day’s traffic readable by the

enemy. I tried to assure the CSO that my opinion

was not motivated by a factor commonly called

“NIH” – “not invented here” but I was overruled by

my military superiors, and properly so, because

neither the SIS nor the SCL had developed anything

that was better than the Hagelin machine, or even

as good, with all its mechanical deficiencies and

cryptographic weaknesses taken into consideration. Accepting, though somewhat reluctantly, the

well-considered directive of the CSO, the SIS pointed out where improvements could be made, and the

desired modifications were incorporated in the

machine, which became known as the Converter M209. Over 100,000 of them were manufactured in

1942-1944 by the Smith-Corona Typewriter

Company at Groton, New York. Here’s an illustration (fig. 140a) showing the machine, which was

extensively used by all our armed forces during

World War II, and here’s another (fig. 140b) showing its internal mechanism. It turned out that under

field conditions the fears upon which I had based

my personal rejection of the Hagelin machine

proved to be fully justified – a great deal of traffic in

it was solved by the Germans, Italians, and

Japanese. If I was chagrined or suffered any

remorse when I learned about the successful enemy

attacks on M-209 traffic, those feelings were generated by my sense of having failed myself to think up

something better than the M-209 despite the shortsighted attitude of the military director of the SCL.

With the introduction of printing telegraph or

teleprinting machines for electrical communications, the need became pressing for a reliable and

practical cryptographic mechanism to be associated

or integrated with such machines. The first apparatus of this sort in the United States, shown in this

photo (fig. 141), was that developed by the

American Telephone and Telegraph Company in

1918, as a more or less simple but ingenious modification of its ordinary printing telegraph. First, a

few explanatory words about the basic principles of

the modern teleprinter may be useful. This principle employs what is called the “Baudot Code,” that

is, a system in which permutations of two different

elements taken in groups of five are employed to

represent characters of the alphabet. Curiously

enough, Francis Bacon was the first to employ such

a “code” way back in the early seventeenth century,

and I showed you the one he used in Lecture No. II

(see figure 31). These two elements in Bacon’s

Page 160

Fig. 140a

Fig. 140b
“code” were a’s and b’s; he used but 24 of the 32

permutations available (25=32). For electrical communications the two elements may be positive and

negative currents of electricity, or the presence and

absence of current, the latter system often referred

to as being composed of “marking’” and “spacing”

elements, respectively. The illustration in figure 142

depicts the Baudot or “five-unit code” in the form of

a paper tape in which there are holes in certain

positions transverse to the length of the tape. The

holes are produced by a perforating mechanism;

the small holes running the length of the tape are

“feed-holes” by means of which the tape is

advanced step by step. You will note that there are

five levels on which the perforations appear. The

letter A, for example, is represented by a perforation only on the 1st and 2nd levels, the 3rd, 4th and

5th levels remaining unperforated; the letter I is

represented by holes in positions 2 and 3, no holes

on the other three levels, etc. The English alphabet

uses twenty-six of the thirty-two permutations; the

remaining six permutations are used to represent

the so-called “stunt characters,” which I will now

explain. The third and fourth characters from the

right-hand end of the tape are two permutations

labeled “letters” and “figures,” respectively. These

are equivalent to the “shift and “unshift” keys on a

typewriter keyboard, for “lower” and “upper” case.

When the “letters” key is depressed, the characters

printed are the twenty-six letters of the alphabet (all

capital letters); when the “figures” key is depressed,

the characters represented are similar to those

printed on a typewriter when the “shift” key is

depressed. The second, third, and fourth permutations at the left-hand end of the tape are also stunt

characters and represent “line feed,” “space,” and

“carriage return,” and they perform electrically in a

teleprinter what is done by hand on a typewriter:

“line feed” causes the paper on which the message

is printed to advance to the next line; “space” does

exactly what depressing the space bar on a typewriter does, etc. When there are no holes anywhere

across the taps, the character is called a “blank”

or “idling” character – nothing happens: the

printer does no printing, nor is there any “stunt”

functioning by the printer, but the tape merely

advances.

In modifying the standard printing telegraph

machine to make it a printing telegraph cipher

machine, or to put the matter in a slightly different way, in developing the printing telegraph

cipher machine, the American Telephone and

Telegraph Company was fortunate in having the

services of a twenty-three-year old communications engineer named Gilbert S. Vernam (fig.

143), who conceived a brilliant principle and an

automatic method for enciphering teleprinter

communications. The principle and method

turned out to be so useful and valuable, not only

in the United States but also internationally, that

it has come to bear his name and is often referred

to as the “Vernam principle,” the “Vernam rule,”

the “Vernam mod-2 addition,” etc. Vernam saw

that if in accordance with some general but

invariant rule the marking and spacing elements

of a five-unit code group were combined one by

Page 161

Fig. 141

Fig. 142
one with those of another five-unit code group,

which would serve as a keying group, and the

resultant five-unit group transmitted over a circuit

and combined at the receiver with the same keying

group in accordance with the same general rule,17

the final result would be the original character.

Vernam conceived the idea early in 1918 or perhaps

late in 1917. I have a copy of Vernam’s circuit diagram, dated and witnessed on 27 February 1918,

but the application for a patent thereon, with his

name as inventor, was filed in the U.S. Patent Office

on 13 September 1918, and Patent No. 1,310,719

was granted on 22 July 1919, covering the invention

entitled a “Secret Signaling System.”

The following more detailed description of

Vernam’s patent on the foregoing cipher system is

extracted from a paper18 written by one of the

AT&T Company’s engineers [R.D. Parker] who was

associated with Mr. Vernam at the time the invention was conceived and who, a few years after

retirement from that company, became one of

NSA’s consultants:

This patent describes an “on-line” system,

each character being enciphered, immediately transmitted, and in turn deciphered

without delay at the receiving terminal.

Thus, characters of a message in perforated tape form are automatically combined

with other or key characters which are

transmitted over the circuit. At the receiver an identical group of key characters is

used to provide signals for combination

with the arriving signals, character by

character, to produce the original message. The combining rule for these operations disclosed in the patent was one in

which like code elements produced

“spaces” and unlike elements, “marks,” as

shown below.

The cipher message tape prepared in this

way is unintelligible in form and may be

sent to the receiving station by messenger

or by mail, or if desired, it may be transmitted by wire or radio and reproduced by

another machine perforator at the receiving point. The cipher tape is there run

through the message transmitter, where

its characters combine with those of a

duplicate key tape to reproduce the original message, which will be printed out in

page form and in “plain text.”

LENGTH OF KEY TAPE

With the system as described above, the

key tape must be at least as long as the sum

of all the message tapes used with it, as the

messages will lose their secrecy to some

extent if the key tape is used repeatedly.

The use of a short repeating key may give

sufficient secrecy for some uses, however.

A roll of tape 8 inches in diameter contains

about 900 feet of tape and would serve to

encipher about 18,000 words counting five

printed characters and a space per word,

without repeating the key. If sent at a average speed of 45 words per minute, this

number of words would require 400 minutes or nearly 7 hours to transmit.

In order to reduce the amount of key tape

required for handling large amounts of

traffic, the “double key” system was

devised.19 In this system two key tapes are

Page 162

Fig. 143
used, the ends of each tape being glued

together to form a loop preferably about

seven feet in circumference. The tapes

should differ in length by one character or

by some number which is not a factor of

the number of characters in either tape. A

separate transmitter is used for each tape

and the characters of the two key tapes are

combined, by a method similar to that

shown in [figure 144], with those of the

message tape to form the cipher message.

The result is the same as though the two

key tapes were first combined to produce a

long single nonrepeating key, which was

later combined with the message tape.

This long, single key is not, strictly speaking, a purely random key throughout its

length as it is made up of combinations of

the two original and comparatively short

key tapes. The characters in this key do not

repeat in the same sequence at comparatively short regular intervals, however, as

would be the case if only one key tape loop

were used.

The number of characters in this equivalent single key is equal to the product of the

number of characters in the two tape

loops, and may easily exceed 600,000

before any part ofthe key begins to repeat.

Ifproper care is taken to use the system so

as to avoid giving information to the

enemy regarding the lengths of the two key

tape loops or their initial settings and to

avoid the possibility of ever reusing any

part of the resultant single key, this system

is extremely difficult to break even by an

expert cryptanalyst having a large number

of messages and full knowledge of the construction of the machine and its method of

operation.

The foregoing double-key-tape system was

placed into operation in 1918 on three start-stop

circuits that were used for intercommunication

among four stations serving Washington, New

York, Hoboken, and Norfolk, and that, according to

Parker [see footnote 20 below], “continued in operation for many months, even after the end of the

war.” In addition, a Signal Corps Company was

organized to go to Europe with new equipment for

installation of printing-telegraph circuits in France.

This Signal Company was about ready to sail when

the armistice was signed on November 11,1918.

On my return to Riverbank in April 1919 upon

being demobilized, I became an interested party in

a rather warm argument conducted by letters

exchanged between Colonel Fabyan, the Chief

Signal Officer, the Director of Military Intelligence,

and the War Department, regarding the cryptosecurity of the cipher printing telegraph system as

used by the Signal Corps. The argument ended by

successfully meeting a challenge by the Signal

Corps to prove Fabyan’s contention. The challenge

consisted in sending Fabyan on 6 October 1919, and

requesting him to solve, the cipher tapes of about

150 messages selected from one day’s traffic in the

system. On 8 December 1919 Fabyan sent a

telegram to the Chief Signal Officer notifying him

that solution had been accomplished. In order to

prove that this was true, I sent a perforated ciphermessage tape to each of the officers named above.

In order to decipher these messages, the Chief

Signal Officer had to use his own key tapes, thus

proving that Riverbank not only had solved the system but had recovered both key tapes that had been

employed in enciphering the challenge messages,

so that Riverbank was in a position to produce the

plain text of any of the latter on request, if further

Page 163

Fig. 144
proof of solution were needed or desired. I wrote a

monograph on the solution, consisting of a basic

paper of twenty-one typewritten pages, an

Addendum 1 of ten pages, an Addendum 2 of twenty-five pages, and an Addendum 3 of six pages; a

copy of each of these documents was sent to

Washington. The solution was accepted with mixed

feelings in Washington, especially on the part of

Brigadier General Marlborough Churchill, the

Director of Military Intelligence, who had signed a

letter to the Chief Signal Officer, dated 8 August

1918, prepared by Captain Yardley to the effect that

the cipher system in question “is considered by this

office to be absolutely indecipherable.”20 General

Churchill had the duty and courtesy to write a congratulatory letter to Colonel Fabyan, dated 24

March 1920, the Imal paragraph of which is as follows:

Your very brilliant scientific achievement

reflects great credit upon you and your

whole personnel. It would be impossible to

exaggerate in paying you and Riverbank

the deserved tribute for this very scholarly

accomplishment.

The paper by Mr. Parker (see footnote 18) closes with the following final paragraph:

Perhaps some day Mr. Friedman will tell

of the part that he and the Riverbank

Laboratories played in the cryptanalytic

phase of this development.

Mr. Parker was not aware that what he suggested had been done not only once but twice. The Ilrst

time was immediately after the solution when

copies of the writeup mentioned a moment ago had

been sent to Washington where they had met the

fate that often happens to documents of limited or

special technical interest – complete disappearance

in the voluminous files of bureaucracy. The second

time was soon after the end of hostilities in World

War II, when it was discovered that a certain outfit

I won’t name was using the double-tape keying system for its teleprinter communications. I rummaged through my own files and uncovered the

handwritten manuscript of certain parts of what I

had written at the close of the successful solution of

that system while at Riverbank. My second writeup

is a classified document, dated 21 July 1948, the

subtitle of which is “Can Cryptologic History

Repeat Itself?” It is possible that this writeup can be

made available to those of you who are interested in

reading it, ifproper authority grants permission.

Mr. Parker’s paper (see footnote 18) devotes a

good deal of space to the contention that the only

reason why the double-tape keying method was

adopted was that the Signal Corps and specifically

its representative, Colonel Mauborgne, “complained about the difficulties that might be experienced in the preparation and distribution of onetime random key tapes and seemed inclined to disapprove of the proposed system because of these

difficulties. Since the system, when properly used,

seemed obviously to be one that gave absolute

secrecy, a discussion arose on the value of the system and on methods that might be devised for the

production and distribution oflong one-time key

tapes having characters arranged at random.”

Parker points out that the original method of use

contemplated the use oflong tapes ofthis nature

and that he and his associates felt the problem 

of producing and distributing long tapes “while 

presenting a challenge, was not impractical.” I am

glad to admit they were right, because during

World War II and for years afterward tapes of this

nature were produced by special machinery (in

some cases as many as five copies being perforated

and the sections numbered automatically in a single operation.) Distribution of and accounting for

the tapes proved practical, too, and aside from 

an occasional error involving the reuse of a 

once-used tape, absolutely secure intercommunication by radio printing telegraphy was assured and

was used between and among large headquarters

where the volume of traffic justified the use of this

equipment. The principal advantage was the simplicity of crypto-operations – no rotors to be set, no

setup of rotors to be enciphered, no checking of

Page 164
equipment by deciphering the message before

transmission, etc.

The AT&T Company Printing Telegraph Cipher

equipments purchased by the Signal Corps were

withdrawn soon after Riverbank proved the double-key-tape system insecure. The machines went

into storage, when in due course most of them were

dismantled. But after I left Riverbank at the end 

of 1920 and had joined the Chief Signal Officer’s

staff in Washington, I induced the Chief Signal

Officer to resuscitate two equipments. These I

employed, believe it or not, in compiling codes,

called Division Field Codes, for use in training or in

an emergency. I won’t undertake to explain how I

performed this stunt, for it was a stunt, but it

worked very successfully. The codes were duly

printed, issued, and used until there was no longer

any need for codes of this type.

Cipher printing telegraphy was placed upon the

shelf and more or less forgotten by Signal Corps

communications engineers from 1920 until soon

after Pearl Harbor. However, the leading members

of the SIS maintained a theoretical cryptanalytic

interest in such equipment, and in 1931 there came

an opportunity to test such theories as were developed by them when a machine produced by the

International Telephone and Telegraph (IT&T)

Company evoked the interest of the Department of

State as a possible answer to the needs of that

department for rapid and secure cryptocommunications by radio. The secretary of state requested

the secretary of war to study the machine. which

was to be associated with a standard teleprinter,

and to study it only from the point of view of security. For this purpose messages enciphered by the

chief of the Communications and Records Division

of the Department of State were provided. Here are

two pictures of the teleprinter attachment (figs.

145a and 145b). It is a source of satisfaction to be

able to tell you that the SIS quickly solved the test

messages and therefore reported that the machine

was quite insecure; but it is with much regret that I

must now tell you who invented and developed the

machine. It was a retired officer of the Signal Corps,

none other than my old friend Colonel Hitt. I was as

embarrassed to tell him about the results of our test

as he was to force himself to listen to what I had to

say about the inadequacies of his brainchild. As is

so often the case, when a competent technician has

to neglect his technical studies because of the pressure of administrative duties, he unfortunately

finds it very difficult to keep abreast of new developments and progress in a field in which he was at

one time an expert. The IT&T Company, having

spent a great deal of money on the development of

a machine that hardly presented any room at all for

improvement because the principles underlying it

were so faulty, dropped further work on it. Colonel

Hitt, I am glad to say, readily survived the disappointment and was well enough in 1942 to be able

to return to active duty during World War II and

retired a second time at the end of hostilities. He

lives a quiet life now, on a small farm near Front

Royal, Virginia.

Page 165

Fig. 145a

Fig. 145b
Beginning about 1938, Mr. Frank B. Rowlett,

one of my associates, and I kept urging that there

was or would be real need for new and improved

machines for protecting teleprinter communications. There was a complete lack of interest in such

apparatus; but what was perhaps a more important

factor in the failure to continue such work in this

field was the lack of Signal Corps funds for research

and development for such work.

Our more or less sudden entry into World War

II after 7 December 1941 immediately brought a

great need for cipher printing telegraphy, especially for radio communication, but there was no apparatus for it whatever – not a single one of those AT&

T Company machines of 1918-1920 was in existence. But the SIS did have drawings in readiness,

and the development of the machines was given as

a priority task to the Teletype Corporation, because

that firm had proved that it had the necessary

know-how when it produced the SIGABA-ECMs for

us. The Navy had less need for cipher printing

telegraphy than the Army because the use of printing telegraphy by radio was then not practicable for

ships at sea. However, the Navy did have a need for

such apparatus for its land communications and

joined the Army in the procurement thereof. The

machines were produced with a remarkable speed

by the Teletype Corporation. Most of them were

allotted to the Army, a few to the Navy. The Army

called the machine the SIGCUM, the Navy called it

CSP-1515. Under heavy use in service, improvements were made in regard to both mechanical and

electrical features and to methods of keying, the use

of indicators, etc. But I must tell you that before

those machines became available in quantity there

was only one recourse: we went back to the use of

double-key-tape method using standard teletype

apparatus. The cipher was practically the same as it

was in 1920, but we had safer methods of key-tape

production and indicators for their use. The SIS

and the equivalent unit in the Navy were not happy

because operators’ errors left messages open to

solution, so that when the new cipher machines

were ready they were pressed into service as soon as

possible, priority given to circuits with heavy traffic.

Cryptographic equipments of the foregoing type

fall in the category of apparatus for protecting literal cryptocommunications because the latter

employ letters of the alphabet; but apparatus for

protecting cifax transmissions, that is, picture or

facsimile transmissions, and apparatus for protecting ciphony transmissions, that is, telephonic communications, were also developed. But there isn’t

time to go into details with regard to machines and

apparatus for these last two categories of cryptoequipment, although the history of their development is rather fascinating and very important. I

cannot refrain, however, from adding that, in every

case except one, the apparatus was produced by

commercial research and development firms with

direct guidance from the cryptologists of the Army

and the Navy. The one exception is, I believe, in the

case of the extremely highsecurity ciphony system

and equipment developed and built by the AT&T

Company. It was called SIGSALY. There were six

terminals, each of which cost over $1,000,000. But

NSA cryptologists and engineers have produced

smaller and better equipments based upon

SIGSALY principles, and such equipments are

bound to play extremely important roles in any

wars in the future.

So much for the history of the developments

and progress in cryptographic apparatus at this

point. I shall return to that phase of cryptologic history before the close of this lecture. Right now I

shall say a few words about the history of the developments and progress in cryptanalytic apparatus.

The solution of modern cryptocommunication

systems has been facilitated and, in some cases,

made possible only by the invention, development,

and application of highly specialized cryptanalytic

machinery, including apparatus for intercepting

and recording certain types of transmission before

cryptanalysis can even be undertaken. One must

understand the basic nature of the problem that

confronts the cryptanalyst when he attempts to

solve one of these modern, very complex cryptosystems. First of all, he must be given the cryptocommunications in a form that makes them visible for

Page 166
inspection and study. Usually they are characters

(letters or numbers) in the case of literal communications, or they are electrical signals of a recordable

type in the case of cifax or ciphony communications. Next, he must have available to him instrumentalities that will assist him in his analytical

work, such as machinery for making frequency

counts, comparisons of sequences, etc., and this, in

the case of complex systems, must be done at high

speed. Cryptanalysis of modern cryptosystems

requires testing a very great number of assumptions and hypotheses because sometimes astronomically large numbers of possibilities, Le., permutations and combinations, must be tested one

after the other until the correct answer is found.

Since the advent of high-speed machinery for such

purposes, including electronic digital computers

about which so much is being heard and read nowadays, the cryptanalyst isn’t discouraged by these

astronomically great numbers of possibilities.

Perhaps long before my time, cryptanalysts in

Europe discovered that the use of sliding strips of

paper could sometimes facilitate reaching a solution to a cryptanalytic problem, but so far as I am

aware the very first cryptanalytic aid made in the

United States is the one shown in figure 146, which

is a picture of what I made at Riverbank and which

I called the Polyalphabet. It was useful in solving

ciphers which today are regarded as being of the

very simplest types. When I came to Washington

after leaving Riverbank, I wasn’t troubled by a

plethora of ideas for cryptanalytic aids – I was preoccupied with devising and inventing cryptographic aids and machines. But I did now and then develop and tryout certain ideas for cryptanalytic aids,

frequency counters, comparison or coincidence

machinery, and the like. Why didn’t I think of IBM

machines? I did, but what good did that do? Did the

Signal Officer have any such machines – or even

one dollar for their rental? You know the answer to

that without my spelling it out. There wasn’t any

use in even suggesting that IBM machines could be

of assistance to me – remember, now, that I’m talking about the years from 1921 to 1933, and in the

last-named year we were in the depths of a great

economic depression. But one day in the summer of

1934 I learned by a devious route (the Army and the

Navy were not then sharing secrets) that the Navy

Code and Signal Section had an IBM machine or

two, and my chagrin was almost unbearable.

Not long afterwards I learned that a certain

division of the Office of the Quartermaster General

in the Munitions Building had an IBM installation

which had been used for accounting purposes in

Page 167

Fig. 146
connection with the CCC – the Civilian

Conservation Corps, established to provide work

and subsistence for young men who could find no

jobs in the depression. I also learned that a new

officer had just been assigned to head that particular division – and that he just had no use for the

newfangled ideas of his predecessor and wanted to

get rid of those nasty IBM machines. But the contract with IBM still had some months to run before

the lease expired, and either the machines would sit

idle or the government would lose money by terminating the contract before the due date of expiration. This annoyed me, but it also gave me an idea,

and I wrote the following memorandum:

30 October 1934

Major Akin:

In many years service here I have never

once “set my heart on” getting something I

felt desirable. But in this case I have set my

heart on the matter because of the tremendous load it would lift off all our backs.

The basic idea of using machinery for code

compilation is mine and is of several years’

standing. The details of the proposed system were developed in collaboration with

Mr. Case of the Int. Bus. Machines Corp.

I regard this as one of my most valuable

contributions to the promotion of the

work for which we are responsible.

Please do your utmost to put this across

for me. If you do, we can really begin to do

worthwhile cryptanalytic work.

Attached to the memo was a brief explanation

amounting to what I’ve told you about that IBM

installation in the Office of the Quartermaster

General. Note that I placed the emphasis upon the

burden that would be lifted from cryptographic

work by using the IBM machinery, thus leaving

more time for cryptanalytic work. This was because

the responsibilities of the SIS for cryptanalytic

operations were at that time restricted purely to

theoretical studies. Studies on cryptanalytic work

on foreign cryptosystems had been a responsibility

of G-2 of the General Staff until 1929, when that

responsibility had been transferred to the Chief

Signal Officer and the Signal Corps. But the Signal

Officer had very little money to use for that purpose, and besides that, the army regulation applicable thereto specifically restricted cryptanalytic

operations on foreign communications to wartime.

And more to the point was that there was no material to work on even if funds had been available,

because the Army had at that time no intercept stations whatever, anywhere in or outside the United

States. But that’s another story, and I’ll proceed to

the next point, which is that my memo to Major

Akin produced results. Just a half month after I

wrote and put it in his “in” basket, I got the

machines moved from the Office of the

Quartermaster General to my own warren in the

Office of the Chief Signal Officer! That memo must

have been potent magic.

Once having demonstrated the machines’ utility to the Chief Signal Officer, the almost prematurely terminated contract with IBM was renewed –

and soon expanded. I don’t know how we could

have managed without such machines during

World War II.

We built or had built for us by IBM and other

concerns adaptors to work with standard IBM

machines; we constructed or had constructed for us

by commercial firms highly specialized cryptanalytic apparatus, machines and complex assemblies of

components. Under wartime pressures fantastic

things were accomplished, and many were the

thrills of gratifying achievement when things that

just couldn’t be done were done - and were of high

importance in military, naval, and air operations

against the enemy.

Even were time available, I couldn’t show you

pictures of some of the high-class gadgets we used;

neither is it permissible to say more than I have

already said about them, even though it is no longer

Page 168
a deep secret that electronic computers are highly

useful in cryptologic work.

To the layman the exploits of professional

cryptanalysts, when those exploits come to light, as,

for example, in the various investigations of the

attack on Pearl Harbor, are much more fascinating

than those of cryptographers, whose achievements

in their field appear in comparison to be dull or

tedious to the layman. But long consideration of the

military importance of COMSEC as against

COMINT leads me to return to something I mentioned at the very beginning of this lecture, when I

made a statement to the effect that cryptography

and cryptanalysis represent the obverse and reverse

faces of the same single coin. In closing this lecture,

I will expand that statement a bit, and in doing so

perhaps formulate a dictum which we may call the

law governing the minting and usage of the cryptologic combat coin. It would run something like this:

When an officer is selected to command a fighting unit, an efficient appointing authority gives him

and entrusts into his care a top secret, magic talisman of great potency, a coin which is called his

cryptologic combat coin, and which, as is usual in

the case of all but trick coins, has two faces, a

COMINT face and a COMSEC face. When given to

him that coin should be in mint condition; it should

be bright and shiny on both faces, and he should

strive his utmost to keep them both that way. If, to

begin with, he is given a coin that is tarnished a bit

on both faces, he is really starting out with a great

handicap, no matter how good he and his forces are

in respect to size, equipment, training, and ability.

If he keeps both faces bright and shiny, he stands a

good chance of winning a battle even if his forces

are inferior in size, etc., compared with those of the

enemy. But if he lets either face of his coin become

dull from indifference, carelessness, or ignorance,

he will almost surely lose the battle, even if his

forces are superior in size, etc., compared with

those of his enemy.

As a remarkable example of the validity of the

foregoing dictum, an example that comes directly

from the two Japanese navy officers who wrote

Midway: The Battle that Doomed Japan (see footnote 11), let me quote the initial paragraphs of the

Preface to their book (p.xiii):

For Japan, the Battle of Midway was

indeed a tragic defeat. The Japanese

Combined Fleet, placing its faith in “quality rather than quantity,” had long trained

and prepared to defeat a numerically superior enemy. Yet at Midway a stronger

Japanese force went down to defeat before

a weaker enemy.

Not only were our participating surface

forces far superior in number to those of

the enemy, but the initiative was in our

hands. Nor were we inferior, qualitatively,

in the crucial element of air strength,

which played the major role throughout

the Pacific War. In spite of this we suffered

a decisive defeat such as the modern

Japanese Navy had never before experienced or even dreamed possible.

Earlier in this lecture I quoted two other paragraphs from this same book, in which the Japanese

authors make perfectly clear the reasons for the loss

of the Battle of Midway, reasons which have also

been stated by other writers. The cryptologic combat coin our navy entrusted to Admiral Nimitz was

highly polished and bright on both sides; the one

the Japanese navy entrusted to Admiral Yamamoto

was dull on both sides to begin with. Admiral

Yamamoto not only didn’t know how tarnished it

was, but lost his life because of his ignorance a couple of years later. Neither he or his superiors had

the experience and knowledge that were necessary

to polish up that coin. It took almost ten years for

the truth of that dictum I formulated for you a

moment ago to become clear to the Japanese navy.

Had they taken quick and full advantage of the

unfortunate leakage of the vital COMINT facts soon

after the Battle for Midway, they could and perhaps

would have come to the proper conclusions long

before they did. Who knows what the results might

Page 169
have been, and the effect thereof, on the outcome of

the war in the Pacific?

Hardly anything of importance in the cryptologic battles of World War II escaped the attention of

Winston Churchill, who even way back in 1915,

when he was First Sea Lord of the British Navy in

World War I, had taken a great interest in cryptology. He made the following final comment on the

Battle of Midway, a comment that is impressive in

its guarded revelations and in its restraint:21

One other lesson stands out. The American

Intelligence system succeeded in penetrating the enemy’s most closely guarded

secrets well in advance of events. Thus

Admiral Nimitz, albeit the weaker, was

twice able to concentrate all the forces he

had in sufficient strength at the right time

and place. When the hour struck this

proved decisive. The importance of secrecy and the consequences of leakage of

information are here proclaimed.

It will probably seem to many of my listeners

and readers that I have paid more tributes to the

achievements of our navy cryptanalysts in World

War II than to those of their army and air force

opposite numbers. If I have done so, I can only say

in extenuation that three factors are here involved.

First, as regards my apparent overlooking of the

contributions of the USAF, I need but remind you

that it wasn’t until after the war was all over that the

Army Air Corps became autonomous; before then

the technical achievements of cryptanalysts of that

Corps were merged with those of the army. Second,

as a member of the Army’s Signal Intelligence

Service, and then the Army Security Agency during

World War II, it is fitting that somebody other than

I blow the trumpets in celebration of our army’s

cryptanalytic achievements. All I will say is that

they were as important as those of our navy, but for

various reasons they have not received much publicity, which is just as well from the point of view of

national security. As a matter of fact, the publicity

regarding our navy’s cryptologic successes comes

very largely from former enemy officers and from

the various official investigations into the attack on

Pearl Harbor, and not from any U.S. Navy personnel. Third, there has been very little leakage with

regard to the army’s cryptanalytic successes except

such as can also be traced back to those Pearl

Harbor investigations. General Eisenhower’s

Crusade in Europe has not one word to say on 

the subjects of signal intelligence, cryptanalysis,

codes, ciphers, or signal security, etc., although 

he does make a few rather caustic remarks about

the failures and errors of his own intelligence 

staff. General Bradley’s book is equally reticent on

these subjects, but I cannot refrain from quoting

one rather amusing episode having to do with

COMSEC:

To identify hills, road junctions, and towns

without our giving our plans away in the

event of an enemy tap on the wire, I had

key features numbered on my war map

and gave copies of those numbers to the

division commanders. It was a makeshift

private code, lax enough to cause Dickson

[Bradley’s G-2] to worry over the security

of our plans.

One morning when I called Major General

Terry Allen, he referred to an obscure

crossroad by its number in this private

code.

“Just a minute, Terry,” I said. “I can’t find

that number on my map.”

“Well, listen carefully, Brad,” he said. “The

enemy may be listening in. I’ll say the

name of the place as fast as I can.”

Dickson overheard this conversation and

threw up his hands. “Security wouldn’t be

much of a problem,” he said, “if only there

were fewer generals in the army.”

General Hap Arnold’s book I’ve mentioned

before and have taken one extract from it. There are

Page 170
several others I might have used, but they are not

too significant in revelations. One volume in the

history of the U.S. Army in World War II, entitled

“The Signal Corps,” contains a few references to the

achievements ofthe Signal Intelligence Service, but

these, too, are not very illuminating. In only one

book by a former U.S. army officer, Colonel Robert

S. Allen, entitled Lucky Forward: The History of

Patton’s Third Army,

22 do I find a specific reference to the help SIS gave Patton. In telling about

Patton’s signal officer, Colonel Hammond, Allen

writes:

One of his ace units was the SIS. A radiointerception agency, commanded by Major

Charles Flint, a young, trigger-smart

expert, it worked closely with G-2 on a dual

mission: maintaining a vigilant security

check on friendly communications and

intercepting enemy messages. The unit

performed outstandingly in both fields.

Its reports plugged up an unwitting leak

from a Mechanized Cavalry source, capable of revealing important troop-movement information to the enemy. And at a

critical period in the Battle of Bastogne,

the unit broke a German coded message

that enabled heavy losses to be inflicted

upon the redoubtable 5 Para Division. The

SIS was particularly fruitful in breakthroughs and fluid situations when the

enemy was on the run and had to use

radio.

The foregoing extract is, of course, far from

spectacular. Indeed, I imagine that it will hardly

bring forth more than a polite yawn from many

members of an audience that has already learned

about the sensational revelations made during the

various Pearl Harbor investigations and about

those famous letters that General Marshall wrote to

Governor Dewey. But there remains this much

more to be said: the achievements of our army’s

cryptologic units both in Washington and in the

field, as well as certain still undisclosed top secret

successes of our navy’s units ashore and afloat, are

locked away in archives, where they will probably

remain for a long, long time. More than this I am

not at liberty to tell you in this lecture.

With this statement I bring this series to a

rather undramatic but I hope meaningful close. I

will wind it up by paraphrasing the last sentence of

the introduction to that important book The Battle

of Midway, from which I have quoted at some

length. The introduction was written by Admiral

Nobutake Kondo, the senior living commander of

the former Imperial Navy, who participated in that

battle: I close this series with the hope that my lectures will serve as material for criticism and reflection.

NOTES

1. (New York: Henry Holt and Co., 1951), 474.

2. The 79th Congress, 2nd Session, Senate

Document No. 244, (Washington: The Government

Printing Office, 1946),232.

3. Ibid., 514.

4. General Albert Wedemeyer, Wedemeyer Reports

(New York: Henry Holt and Company, 1958),430.

5. A good bibliographical survey of items concerning

the attack up to the year 1955 will be found in the following: Louis Morton, Pearl Harbor in Perspective, U.S.

Naval Institute Proceedings, Vol. 81, No.4, Whole No.

626, April 1955,461-8.

6. The Memoirs of Cordell Hull (New York: The

MacMillan Co.), Vol. II, 998, 1013, 1035, 1055, 1056-7,

1060, 1063, 1068, 1074, 1077, 1087, 1092, 1095, 1096,

1099-100.

7. Henry L.Stimson and McGeorge Bundy, On Active

Service in Peace and War (New York: Harper &

Brothers, 1947),391-94, 454-5.

8. Herbert Feis, The Road to Pearl Harbor

(Princeton: The Princeton University Press, 1950), vii,

and 219-340, Passim. (See index: under “Magic” on

350.) 9. Husband E. Kimmel, Admiral Kimmel’s Story

(Chicago: Henry Regnery Co., 1954).

10. Sherman Miles, “Pearl Harbor in Retrospect,”

The Atlantic Monthly, Vol. 182, No. 1, July 1948,65-72.

11. Midway, The Battle that Doomed Japan: The

Japanese Navy’s Story, by Matsuo Fuchida and

Matasake Okumiya (Annapolis: U.S. Naval Institute

Page 171
Publication, 1955), 131, and 232. Admiral Morrison actually wrote:

“Midway was a victory of intelligence bravely and

wisely applied.” See Vol. IV of his History of U.S. Navy

Operations in the Pacific: Coral Sea, Midway, and

Submarine Actions, May-August 1942. (New York:

Little, Brown, 1944), 185. It is interesting to note that

Admiral Morrison, in an article entitled “Lessons of

Pearl Harbor” published in the Saturday Evening Post,

October 28, 1961, concludes, “It was the setup at

Washington and at Pearl, not individual stupidity, which

confused what was going on. No one person knew the

intelligence picture; no one person was responsible for

the defense of Pearl Harbor; too many people assumed

that others were taking precautions that they failed to

take.”

12. Admiral Halsey's Story (New York: McGrawHill, 1947), 155-157.

13. The Two Bookes of the proficience and advancement of Learning, (London, 1605), 61. This book is commonly known as The Advancement of Learning. Some

18 years later Bacon saw no reason to change his comment in his De Augmentis Scientiarum, (London, 1623).

In fact, he strengthened it by making it read: “... but the

rawness and unskillfulness of Secretaries, and Clarks, in

the Courts of Princes, is such that many times the greatest matters are committed to futile and weak Cyphers.”

(Gilbert Wats’ translation, 1640, 270.)

14. Les Chiffres secrets devoiles.

15. Comptes Rendus, Marseilles, Vol. XX, 160-65.

16. L’art de chiffrer et de dechiffrer les depeches

secretes, (Paris, 1893), 100.

17. In this system, which uses only two different

symbols or elements, the so-called “binary code,” the

combining rule is its own inverse.

18. R. D. Parker, “Recollections Concerning the Birth

of One-Time Tape and Printing-Telegraph Machine

Cryptography,” NSA Technical Journal, Vol. I, No.2,July

1956, 103-14.

19. By L.F. Morehouse, an A.T. & T. Company equipment engineer. See u.s. Patent No. 1,356,546, “Ciphering

System,” granted 26 October 1920-W.F.F.

20. The letter consisting of a single paragraph stated:

“1. The mechanical means of enciphering messages with

an arbitrary, meaningless running key of 999,000 letters, provided no two messages are enciphered at the

same point on the tape as explained to Major

Mauborgne, Signal Corps, and Captain Yardley, Military

Intelligence Branch, by officials of the American

Telegraph and Telephone Company, is considered by

this office to be absolutely indecipherable.”

21. The Hinge of Fate, Vol. IV (Boston: Houghton

Mifflin Co., 1950), 252-53.

22. (New York: The Vanguard Press, Inc., 1957), 56.

The author makes some quite caustic comments 

about the failure of the intelligence staffs to make use of

the the intelligence they were furnished. They are worth

reading.

Page 172
MAGIC WAS THE WORD FOR IT

U.S. citizens discovered last week that perhaps

their most potent secret weapon of World War II

was not radar, not the VT fuse, not the atom bomb

– but a harmless little machine that cryptographers

painstakingly constructed in a hidden room at Fort

Washington.

With this machine, built after years of trial and

error, of inference and deduction, cryptographers

had duplicated the decoding devices used in Tokyo.

Testimony before the Pearl Harbor Committee had

already shown that the machine – known in Army

code as “Magic” – was in use long before December

7, 1941, had given ample warning of the Jap’s sneak

attack – if only U.S. brass hats had been smart

enough to realize it (Time, December 10). Now

General Marshall continued the story of “Magic’s”

magic. It had:

Enabled a relatively small U.S. force to intercept

a Jap invasion fleet, win a decisive victory in the

Battle of the Coral Sea, thus saving Australia and

New Zealand.

Given the U.S. full advance information on the

size of the Jap forces advancing on Midway,

enabled the Navy to concentrate ships which otherwise might have been 3,000 miles away, thus set up

an ambush which proved to be the turning-point

victory of the Pacific war.

Directed U.S. submarines unerringly to the sea

lanes where Japanese convoys would be passing.

By decoding messages from Japan’s

Ambassador Oshima in Berlin, often reporting

interviews with Hitler, given our forces invaluable

information on German war plans.

UNEASY SECRET

So priceless a possession was Magic that the

U.S. high command lived in constant fear that the

Japs would discover the secret, change their code

machinery, force U.S. cryptographers to start all

over again.

General Marshall had a long series of bad

moments after U.S. flyers, showing a suspicious

amount of foresight, shot down Admiral

Yamamoto’s plane at Bougainville in 1943. Gossip

rustled through the Pacific and into Washington

cocktail parties; General Marshall got to the point

of asking the FBI to find an officer “who could be

made an example of.” (The FBI, fearful of looking

like a Gestapo, refused.)

Once a decoder was caught in Boston trying to

sell the secret. Once, well-meaning agents of the

Office of Strategic Services ransacked the Japanese

Embassy in Lisbon, whereupon the Japs adopted a

new code for military attachés. This code remained

unbroken more than a year later.1 The worst scare

of all came during the 1944 presidential campaign,

when George Marshall heard that Thomas E.

Dewey knew the secret and might refer to it in

speeches (see below).

Yet for all these fears, the Japs never discovered

that the United States was decoding their messages.

Even after the surrender the Army still used Magic

as a guide to occupation moves: though it had once

been planned to send a whole army into Korea,

Magic showed that a single regiment would be

enough.

Page 173

Appendix I

From Time, 17 December 1945
SECRET KEPT

The letter, on stationery of the Chief of Staffs

Office, bore a bold heading: TOP SECRET. FOR

MR. DEWEY’S EYES ONLY. Candidate Thomas E.

Dewey, his curiosity piqued, read rapidly through

the first two paragraphs:

I am writing you without the knowledge of

any other person except Admiral King

(who concurs) because we are approaching a grave dilemma in the political reactions of Congress regarding Pearl Harbor.

What I have to tell you below is of such a

highly secret nature that I feel compelled

to ask you either to accept it on the basis of

your not communicating its contents to

any other person and returning this letter

or not reading any further and returning

the letter to the bearer.

Tom Dewey looked up from the typewritten

page. As he did, the word cryptograph, a few paragraphs below, flashed into his vision like a red traffic light. He made his decision quickly, folded the

letter, handed it back. Colonel Carter W. Clarke (in

mufti), who had flown from Washington to Tulsa to

catch up with Tom Dewey’s campaign, went back,

his mission uncompleted.

YOU HAVE MY WORD

It was September 1944. The campaign train

rolled up through the Midwest, returned to Albany.

A few days later, Tom Dewey received another visit

from Colonel Clarke.2

The Colonel, again in civilian clothes, handed

over another letter from General Marshall. The

General had changed his mind somewhat:

I am quite willing to have you read what

comes hereafter with the understanding

that you are bound not to communicate to

any other person any portions on which

you do not now have or later receive factual knowledge from some other source than

myself. . .. You have my word that neither

the Secretary of War nor the President has

any intimation whatsoever that such a letter has been addressed to you. . . .

THE LOCKED FILE

This time Tom Dewey read on. As he turned the

pages, he became the first man outside the high

command to know the full story of “Magic” and

what it was accomplishing in the war against the

Japs (see above). The letter closed with a plea:

I am presenting this matter to you, for

your secret information, in the hope that

you will see your way clear to avoid the

tragic results with which we are threatened in the present political campaign.

Tom Dewey locked the letter in his files, went

back to his electioneering. Though he had known

before that the United States had cracked the Jap

code, had suspected that this information cast

grave doubts on Franklin Roosevelt’s role before

Pearl Harbor, he held his tongue. The War

Department’s most valuable secret was kept out of

the campaign.

MEETING AT A FUNERAL

Recounting this story at the Pearl Harbor hearing last week, General Marshall recalled that he and

Tom Dewey had never discussed the matter in person until they met at Franklin Roosevelt’s funeral

last April: “I asked Mr. Dewey to come with me to

the War Department and I showed him current

Magic showing Japanese movements. His attitude

was friendly and gracious.”

Had Marshall ever told Franklin Roosevelt of

the letters to Dewey? Said Marshall: “The President

died without knowing of it.”

Page 174
SECRET LOST

The Pearl Harbor Committee blithely tossed

away one still-secret U.S. weapon. George

Marshall’s letters to Governor Dewey (see above)

mentioned that the United States, with the help of

the British, had decoded German as well as

Japanese messages. George Marshall begged the

Committee to cut out these references. The

Committee refused.

Publication of the letters thus gave the Germans

their first knowledge that their code had been broken. It was also a breach of diplomatic confidence

with the British, who had let the United States in on

the secret on the understanding that it would be

kept.

ANATOMY OF A CONFUSION

Up to the witness stand stepped Lieut. General

Leonard T. Gerow, chief of the Army’s War Plans

Division in 1941, to accept full blame for one of

Pearl Harbor’s most egregious errors. On

November 27, a sharp warning of impending hostilities had gone out from General Marshall to Lieut.

General Walter C. Short in Hawaii. On November

28, General Short replied that he had ordered an

alert against sabotage – which was like saying he

had a butterfly net ready for a tiger. Yet his reply

was never challenged by Washington. Why?

Explained General Gerow: he thought the 

Short message was an answer to other communications. Said he: “If there is any responsibility in the 

War Department for failure. . . I accept that responsibility.”

Then up stepped General Marshall himself to

take part of the blame. He didn’t recall seeing the

Short message; he should have. “That was my

opportunity to intervene and I didn’t take it,” he

confessed. “Just why, I do not know.”

FOURTEEN POINTS

The week’s testimony also shed light on the

warning that came too late – the message Walter

Short received on December 7 at 2:58 p.m. Hawaii

time informing him that the Japs were on the way.

On the night of December 6, Major General

Sherman Miles, Chief of Intelligence, received 

from “Magic” decoders the first thirteen points of

the strongly worded, final Jap diplomatic note

being sent from Tokyo to its envoys in Washington.

Next morning, some time between 7 and 

8 o’clock, an assistant telephoned that he had

“important” information. General Miles reached

his office at 9 o’clock.

General Marshall had risen early, breakfasted at

8, looked over the Sunday papers, gone out for 

a horseback ride. (He usually rode for 50 minutes.)

He was in the shower when an urgent message

arrived by telephone from General Miles’ assistant.

He finished his bath, dressed quickly and 

went straight to the War Department. The time:

11:25 a.m.

WHO’S CONFUSED?

A hastily gathered staff meeting decided that

the Jap note meant war, that a warning should go

immediately to Hawaii, the Philippines, the West

Coast, the Canal. General Marshall called Admiral

Harold R. (“Betty”) Stark, then Chief of Naval

Operations. “Betty” Stark thought by some obscure

reasoning that further warnings would “only confuse” field commanders.

General Marshall wrote out a warning anyway,

called Admiral Stark again to read it. Stark decided

on second thought that the warning might as well

go to Navy commanders as well. General Marshall

sent it on to the Signal Corps that promised, according to General Miles, that it would be delivered in

20 minutes. It was then 11:50 a.m.; the attack was

one hour and ten minutes away.

Page 175
Instead of 20 minutes, the Signal Corps took

eight hours and 28 minutes to get the message to

Short (by commercial cable instead of Army radio).

Nobody had bothered to check up on the Signal

Corps; the General Staff took for granted that the

message was going full speed ahead.

Why hadn’t General Marshall used the telephone? His explanation: he knew that many phone

calls – including transatlantic talks between

Franklin Roosevelt and Winston Churchill – had

been tapped; he feared that the Japs would intercept his call and label it an “overt act.” Anyway, he

said, even if he had phoned he would first have

called the Philippines, where he thought the real

danger lay.

Said George Marshall: “We thought Hawaii was

the most improbable [target] of all. . . . I was

inclined to feel the hazards were too great and they

would not risk it.”

Page 176
The Letters from General Marshall to

Governor Dewey, 25 and 27 September 1944

The Marshall-Dewey correspondence is so

important in cryptologic history that I feel the

whole of it should be included even in this brief history. When the letter was written, it was, of course,

TOP SECRET and it was only under great pressure

from certain members of the Joint Congressional

Committee that General Marshall revealed its contents.3 Thus, it came into the public domain not

only on the very day that General Marshall was

forced to place it in evidence – its publication

caused a great sensation in the newspapers – but

also when the forty volumes of the hearings of that

committee were published and put on sale by the

Superintendent of Documents of the Government

Printing Office. The disclosure of the contents of

the Marshall-Dewey correspondence was indeed

such a sensation that Life printed the whole of it in

its issue of 17 December 1945, with the following

introduction:

MARSHALL-DEWEY LETTERS

General Told Candidate We Had Broken Jap

Code

During the 1944 election campaign General

George C. Marshall wrote two letters to Republican

candidate Thomas E. Dewey, telling him that Army

cryptographers had broken the Japanese “ultra”

code. This fact was first revealed in a story by Life

Editor John Chamberlain, which appeared in Life,

Sept. 24. Marshall’s purpose, Chamberlain wrote,

was to forestall Dewey’s revelation of that fact in a

possible attack on the Roosevelt administration’s

Japanese policy before Pearl Harbor. The actual

text of the letters emained secret until last week,

when General Marshall appeared before the

Congressional committee investigating Pearl

Harbor and made the letters public. They appear

below.

When he had finished reading the first two

paragraphs of the first letter, Governor Dewey

stopped because, as the Chamberlain article reported, “the letter might possibly contain material

which had already come from other sources, 

and that anyway, a candidate for President was in

no position to make blind promises.” General

Marshall sent the letter back again with an 

introduction which relieved the governor of binding

conditions. This time Dewey read the letter and

after much thought and discussion decided not to

make use during the campaign of any information

he previously had.

First Letter

TOP SECRET

(FOR MR. DEWEY’S EYES ONLY)

25 September 1944

My Dear Governor:

I am writing you without the knowledge of

any other person except Admiral King

(who concurs) because we are approaching a grave dilemma in the political reactions of Congress regarding Pearl Harbor.

What I have to tell you below is of such a

highly secret nature that I feel compelled

to ask you either to accept it on the basis of

your not communicating its contents to

any other person and returning the letter

or not reading it any further and returning

the letter to the bearer.

Page 177

Appendix II
I should have preferred to talk to you in

person but I could not devise a method

that would not be subject to press and

radio reactions as to why the Chief of Staff

of the Army would be seeking an interview

with you at this particular moment.

Therefore, I have turned to the method of

this letter, to be delivered by hand to you

by Colonel Carter Clarke, who incidentally

has charge of the most secret documents of

the War and Navy Departments.

In brief, the military dilemma resulting

from Congressional political battles of the

political campaign is this:

The most vital evidence in the Pearl

Harbor matter consists of our intercepts of

the Japanese diplomatic communications.

Over a period of years our cryptograph

people analyzed the character of the

machine the Japanese were using for

encoding their diplomatic messages.

Based on this, a corresponding machine

was built by us which deciphers their messages.

Therefore, we possessed a wealth of information regarding their moves in the

Pacific, which in turn was furnished the

State Department – rather than, as is popularly supposed, the State Department

providing us with information – but which

unfortunately made no reference whatever to intentions toward Hawaii until the

last message before Dec. 7, which did not

reach our hands until the following day,

Dec. 8.

Now the point to the present dilemma is

that we have gone ahead with this business

of deciphering their codes until we possess

other codes, German as well as Japanese,

but our main basis of information regarding Hitler’s intentions in Europe is

obtained from Baron Oshima’s message

from Berlin reporting his interviews with

Hitler and other officials to the Japanese

Government. These are still in the codes

involved in the Pearl Harbor events.

To explain further the critical nature of

this setup which would be wiped out

almost in an instant if the least suspicion

were aroused regarding it, the Battle of the

Coral Sea was based on deciphered messages and therefore our ships were in the

right place at the right time. Further, we

were able to concentrate our limited forces

to meet their advances on Midway when

otherwise we almost certainly would have

been some 3,000 miles out of place.4

We had full information of the strength of

their forces in that advance and also of the

smaller force directed against the

Aleutians which finally landed troops on

Attu and Kiska.

Operations in the Pacific are largely guided by the information we obtain of

Japanese deployments. We know their

strength in various garrisons, the rations

and other stores continuing available to

them and what is of vast importance, we

check their fleet movements and the movements of their convoys.

The heavy losses reported from time to

time which they sustain by reason of our

submarine action largely results from the

fact that we know the sailing dates and the

routes of their convoys and can notify out

submarines to lie in wait at the proper

point.

The current raids by Admiral Halsey’s carrier forces on Japanese shipping in Manila

Bay and elsewhere were largely based in

timing on the known movements on

Japanese convoys, two of which were

Page 178
caught, as anticipated, in his destructive

attacks.

You will understand from the foregoing

the utter tragic consequences if the present political debates regarding Pearl

Harbor disclose to the enemy, German or

Jap, any suspicion of the vital sources of

information we now possess.

The Roberts report on Pearl Harbor had to

have withdrawn from it all reference to

this highly secret matter, therefore in portions it necessarily appeared incomplete.

The same reason which dictated that

course is even more important today

because our sources have been greatly

elaborated.

As a further example of the delicacy of the

situation, some of Donovan’s people (the

OSS), without telling us, instituted a secret

search of the Japanese Embassy offices in

Portugal. As a result the entire military

attaché Japanese code all over the world

was changed, and though this occurred

over a year ago, we have not yet been able

to break the new code and have thus lost

this invaluable information source, particularly regarding the European situation.

A recent speech in Congress by

Representative Harness would clearly suggest to the Japanese that we have been

reading their codes though Mr. Harness

and the American public would probably

not draw any such conclusion.

The conduct of General Eisenhower’s campaign and of all operations in the Pacific

are closely related in conception and timing to the information we secretly obtain

through these intercepted codes. They

contribute greatly to the victory and

tremendously to the saving of American

lives, both in the conduct of current operations and in looking toward the early termination of the war.

I am presenting this matter to you, for

your secret information, in the hope that

you will see your way clear to avoid the

tragic results with which we are now

threatened in the present political campaign. I might add that the recent action of

Congress in requiring Army and Navy

investigations for action before certain

dates has compelled me to bring back the

corps commander, General Gerow, whose

troops are fighting at Trier, to testify here

while the Germans are counterattacking

his forces there. This, however, is a very

minor matter compared to the loss of our

code information.5

Please return this letter by bearer. I will

hold it in my secret file subject to your reference should you so desire.

Faithfully yours,

G.C. Marshall

Second Letter

TOP SECRET

(FOR MR. DEWEY’S EYES ONLY)

27 September 1944

My Dear Governor:

Colonel Clarke, my messenger to you of

yesterday, Sept. 26, has reported the result

of his delivery of my letter dated Sept. 25.

As I understand him you (A) were unwilling to commit yourself to any agreement

regarding “not communicating its contents to any other person” in view of the

fact that you felt you already knew certain

of the things probably already referred to

in the letter, as suggested to you by seeing

the word “cryptograph,” and (B) you could

not feel that such a letter as this to a

Presidential candidate could have been

Page 179
addressed to you by an officer in my position without the knowledge of the

President.

As to (A) above I am quite willing to have

you read what comes hereafter with the

understanding that you are bound not to

communicate to any other person any portions on which you do not now have or

later receive factual information from

some other source than myself. As to (B)

above you have my word that neither the

Secretary of War nor the President has any

intimation whatsoever that such a letter

has been addressed to you or that the

preparation or sending of such a communication was being considered.

I assure you that the only persons who saw

or know of the existence of either this letter or my letter to you dated Sept. 25 are

Admiral King, seven key officers responsible for security of military communications, and my secretary who typed these

letters.

I am trying my best to make plain to you

that this letter is being addressed to you

solely on my initiative, Admiral King having been consulted only after the letter was

drafted, and I am persisting in the matter

because the military hazards involved are

so serious that I feel some action is necessary to protect the interests of our armed

forces.

(The second letter then repeated substantially

the text of the first letter except for the first two

paragraphs.)

Life failed to note that the last two sentences in

the penultimate paragraph of the “First Letter”

were omitted from that paragraph in the “Second

Letter,” but there is no explanation for the omission.6 Perhaps it was simply for the sake of brevity,

but this seems improbable.

In my first lecture I called attention to the fact

that the account given in the Time article gives

credit to Army cryptanalysts for providing the

secret intelligence “which enabled our navy to win

such spectacular battles as those of the Coral Sea

and Midway, and to waylay Japanese convoys,”

whereas the credit for the communications intelligence which enabled our navy to win those battles

was produced by Navy cryptanalysts. One cannot

blame the editors of Time for making such a bad

error because the source of the error can be traced

directly to General Marshall’s letter itself. Several

years ago I asked my friend Colonel Clarke, who,

you will recall, carried General Marshall’s letter to

Governor Dewey, how such an error had crept into

General Marshall’s letter and was told that the letter that had been prepared for General Marshall’s

signature did not meet with the General’s wholehearted approval and that the General himself had

modified it. Perhaps that is how the error to which

I have referred crept into it. One could hardly

expect General Marshall to be entirely familiar with

the technical cryptanalytic details involved in what

he wanted to tell Governor Dewey, nor should one

criticize him for not being able, in his very busy

days and under very heavy pressure of events, to

bear in mind or even to know about the differences

between the enemy systems worked upon by the

respective and separate Army and Navy cryptanalytic organizations. It is of course possible, indeed it

may be, that in the cases of certain important naval

operations valuable COMINT came from messages

read by Army cryptanalysts, and this may be what

confused General Marshall in implying that all the

credit belonged to them because of their solution of

the Japanese highest-level diplomatic cryptosystems, the one that used the so called “Purple Code,”

which wasn’t a code but a cipher machine.

Since the period during which the disclosures of

the joint congressional investigation were made,

disclosures which were disastrous so far as the

important accomplishments of the two services

before and after the Pearl Harbor attack in the field

of communications intelligence, much has been

written and is now in the public domain regarding

Page 180
those accomplishments, but fortunately no technical details of significance have been disclosed.

NOTES

1. While I have no recollection of the Boston business. I shall never forget the Lisbon incident. – W.F.F.

2. “A few days later...” But note that the first letter is

dated 25 September 1944, the second, 27 September. It

is possible that Colonel Clarke was unable to deliver the

letter, but my recollection is that he did deliver it the very

next day.- W.F.F.

3. So far as I am aware it has neither been ascertained nor disclosed, if known, who gave Governor

Dewey the information. But it is a fact that as a patriotic

citizen, he acceded to General Marshall’s request – he

made no use whatever of the vital secret information

during the campaign or after it. Time’s account specifically states that Dewey “held his tongue. The War

Department’s most valuable secret was kept out of the

campaign”. I know this to be true.- W.F.F.

4. In regard to this and the succeeding four paragraphs, see my comment below (p.129).

5. The last two sentences in this paragraph were

omitted from the Second Letter. See footnote 6.

6. The sentence beginning “I might add. . .” and the

one beginning “This, however is. . .” were omitted.

Page 181
Page 182
Allen, Robert S. Lucky Forward: The History of

Patton’s Third Army. New York: The Vanguard Press,

Inc., 1957.

Bacon, Sir Francis. Advancement of Learning.

London, 1604.

Bacon, Sir Francis. The Advancement of Learning.

(Translated by Gilbert Wats, 1640).

Bacon, Sir Francis. De Augmentis Scientiarum.

London, 1623.

Bakeless, Colonel. John. Turncoats, Traitors and

Heroes. Lippincott, 1959.

Bates, David H. “Lincoln in the Telegraph Office,”

Century Magazine. Vol. LXXIV, Nos. 1-5, MaySeptember, 1907.

Bates, David H. Lincoln in the Telegraph Office.

New York: Appleton-Century Company, 1907, reprinted

1939.

Battles and Leaders of the Civil War. New York: The

Century Co., 1884, 581.

Bazeries. Les Chiffres secrets dévoilés. Paris, 1901.

Bazeries. “Cryptographe à 20 Rondelles - alphabets

(25 lettres par alphabet),” Comptes Rendus. Marseilles,

Vol. XX, 1891.

Bradley, General Omar. A Soldier’s Story. New York:

Henry Holt and Co., 1951.

Brown, J. Willard. The Signal Corps, U.S.A., in the

War of the Rebellion. Boston: U.S. Veteran Signal Corps

Association, 1896.

Budge, Dr. E.A. Wallis. The Rosetta Stone. Trustees

of the British Museum, 1922.

Champollion, Jean Francois. Hieroglyphic

Dictionary.

Champollion, Jean Francois. Egyptian Grammar.

Churchill, Winston. The Hinge of Fate, Vol. IV.

Boston: Houghton Mifflin Co., 1950.

“The Cipher Dispatches.” The New York Tribune.

Extra No. 44, New York, (14 January) 1879. [Tilden scandal]

Counter-espionage, or keys for all secret communications. Paris 1793.

Drioton, Prof. Étienne. Revue D’Égyptologié, Paris,

1933.

Drioton, Prof. Étienne. “Decipherment of Egyptian

Hieroglyphics,” La Science Moderne. August 1924.

Ellis, Kenneth L. The Post Office in the Eighteenth

Century: A Study in Administrative History. London:

Oxford University Press, 1958.

Falconer, James. Cryptomenysis Patefacta: Or the

Art of Secret Information Disclosed Without a Key.

London, 1685.

Feis, Herbert. The Road to Pearl Harbor. Princeton:

The Princeton University Press, 1950.

Friedman, William F. American Army Field Codes

in the American Expeditionary Forces during the First

World War. Government Printing Office, 1942.

Friedman, William F. Analysis of a MechanicoElectrical Cryptograph, Part I (1934), Part II, 1935.

Friedman, William F. Field Codes Used by the

German Army During the World War. 1919.

Friedman, William F., and Elizebeth S. The

Shakespearean Ciphers Examined. Cambridge

University Press, 1957.

Fuchida, Matsuo, and Matasake Okumiya. Midway,

The Battle that Doomed Japan: The Japanese Navy’s

Story. Annapolis: U.S. Naval Institute Publication, 1955.

Giverge, General. Cours de Cryptographie. 1925.

Gregory, Lieutenant Colonel J.F. Telegraphic Code

to Insure Secrecy in the Transmission of Telegrams.

Government Printing Office, 1886.

Gylden, Yves. Chifferbråernas Insatser I

Världskriget Till Lands. [Translation by William F.

Friedman, The Contribution of the Cryptographic

Bureaus in the World War. Government Printing Office,

1936.]

Halsey, Fleet Admiral William F. Admiral Halsey’s

Story. New York: McGraw-Hill, 1947.

Hassard, John R.G. “Cryptography in Politics,” The

North American Review. Vol. CXXVIII, No. 268, March

1879. [Tilden scandal]

Page 183

BIBLIOGRAPHY

[for Friedman Lectures]
Haswell, John H. “Secret Writing,” Century

Magazine, Vol. LXXXV, November 1912.

Hitt, Captain Parker. Manual for the Solution of

Military Ciphers. Fort Leavenworth, Kansas: Army

Service Schools Press, 1916.

Holden, Edward S. The Cipher Dispatches. New

York, 1879. [Tilden scandal]

Hull, Cordell. The Memoirs of Cordell Hull. New

York: The MacMillan Co.,1948.

James, Admiral Sir William. The Eyes of the Navy.

London: Methuen & Co., 1955.

Kimmel, Husband E. Admiral Kimmel’s Story.

Chicago: Henry Regnery Co., 1954.

Mauborgne, 1st Lieutenant. J.O. An Advanced

Problem in Cryptography and its Solution. Fort

Leavenworth, Kansas: Army Service Schools Press, 1914.

Mendelsohn, Captain Charles J. Studies in German

Diplomatic Codes Employed During the World War.

Government Printing Office, 1937.

Miles, Sherman. “Pearl Harbor in Retrospect,” The

Atlantic Monthly. Vol. 182, No.1, July 1948.

Morison, Admiral Samuel E. History of U.S. Navy

Operations in the Pacific. Vol. IV: “Coral Sea, Midway,

and Submarine Actions, May-August 1942.” New York:

Little, Brown, 1944.

Morton, Louis. Pearl Harbor in Perspective. U.S.

Naval Institute Proceedings, Vol. 81, No. 4, Whole No.

626, April 1955.

Myer, Colonel. Albert J. A Manual of Signals: for the

use of signal officers in the field. Washington, D.C.:

Signal Officer of the Army, 1864.

O’Brien, J .E. “Telegraphing in Battle,” Century

Magazine. XXXVIII, September 1889.

Parker, R.D. “Recollections Concerning the Birth of

One-Time Tape and Printing-Telegraph Machine

Cryptography.” NSA Technical Journal. Vol. 1, No.2,

July 1956.

Plum, Colonel William R. The Military Telegraph

during the Civil War. Chicago, 1882.

Poe, Edgar Allan. “The Gold Bug.”

Several Machine Ciphers and Methods for their

Solution. Riverbank Publication No. 20, 1918.

Slater, Robert. Telegraphic Code to Ensure Secresy

[sic] in the Transmission of Telegrams. 1870. [a.k.a.

Slater’s Code]

Stern, Philip Van Doren. Secret Missions of the Civil

War. New York: Rand McNally and Co., 1951

Stimson, Henry L., and McGeorge Bundy. On Active

Service in Peace and War. New York: Harper &

Brothers, 1947.

Taylor, Dr. Charles E. “The Signal and Secret Service

of the Confederate States,” Confederate Veteran, Vol.

XL, August-September 1932.

Time, 17 December 1945.

Tuchman, Barbara. The Zimmermann Telegram.

New York: Viking Press, 1958.

U.S. House Miscellaneous Documents, Vol. 5, 45th

Congress, 3rd Session, 1878-79. [Tilden scandal]

Viaris, Marquis de. L ‘art de chiffrer et déchiffrer les

dépêches secrètes. Paris, 1893.

Wedemeyer, General Albert C. Wedemeyer Reports.

New York: Henry Holt and Company,1958.

Wheatstone, Sir Charles. The Scientific Papers of Sir

Charles Wheatstone. London: Physical Society of

London, 1879.

Wimsatt, Professor W.K. “What Poe Knew About

Cryptography,” Publications of the Modern Language

Association of America. New York, Vol. LVIII, No.3,

September 1943.

Yardley, Herbert O. The American Black Chamber.

Indianapolis: Bobbs-Merrill Co., 1931.

Young, Dr. Thomas. “Studies on the Rosetta Stone,”

Encyclopaedia Britannica. Vol. 4, 1819.

Page 184
Editor’s Note: From a reprint in Cryptologic

Spectrum (Vol. 4, No.1), Winter 1974.

PROLOGUE

When I joined the U.S. Army to enter the cryptologic service of my adopted country on February

11, 1941, William F. Friedman was already a legendary figure in my eyes. I had read two early

papers of his, “L’indice de coincidence et ses applications en cryptographie” and “Application des

méthodes de la statisque à la cryptographie,” when

I was living in Paris in 1934, concertizing as a flute

soloist throughout Europe while privately pursuing

an active hobby of cryptology, which I felt would be

my niche when the time came for me to enter the

army. (Besides the U.S. Army, I was also liable for

service in the Greek, Egyptian, and Turkish armies,

and barely missed being in one of the latter.) As a

member of the original group of twenty-eight students in the Cryptographic School at Fort

Monmouth, New Jersey, I was overjoyed when I

found that Mr. Friedman’s texts on military cryptanalysis were to be our Old and New Testaments

combined.1

I did not meet William Friedman until after our

school moved in October of 1942 to Vint Hill Farms

Station, Warrenton, Virginia. The previous summer

I had been promised a direct commission by the

Headquarters staff of Fort Monmouth. At that time

I was, as a senior private first class – I had the rank

that went with the job – head of the language

department and taught Italian and cryptanalysis

and, since I was presumably indispensable on

weekdays, pulled KP only on Saturdays and

Sundays. Tired of waiting, I went to Officer

Candidate School and graduated with my class in

August 1942.

It was at Vint Hill that Mr. Friedman first paid

us a visit, and we were all properly impressed at the

dapper figure with the Adolphe Menjou moustache,

the characteristic bow tie, and the two-tone blackand-white shoes – the cryptologic giant who asked

the most searching questions and understood our

answers even before we had finished our explanations. Having been at Vint Hill for fourteen months

and, thinking that I might be stuck there for the

duration of the war (I was Chief Instructor in cryptanalytics, with several hundred students in the

school), I seized the opportunity, when Mr.

Friedman again visited us, to ask him to get me out

of there. In two weeks I was transferred to

Arlington Hall Station, where I was to have been

assigned to Mr. Friedman for four months to write

a course in operational cryptanalysis and then to

have been sent to Europe. The army, though, has a

wonderful way of working. The officer to whom I

was to have reported was on leave; I reported to the

wrong officer, was sent to the wrong building,

found myself two weeks later enrolled in a Japanese

course, and it was made perfectly clear that my destiny was eventual service in the Far East. Mr.

Friedman discovered my predicament too late to do

anything about it, so after a year at Arlington Hall I

went to New Delhi as an Assistant Signal

Intelligence Officer for the China-Burma-India

Theater. When the war was over, I was sent as a

junior captain to Leavenworth (to the Command

and General Staff College – not to that other place).

When I graduated in February 1946, Mr. Friedman

requested my assignment to the Army Security

Agency (ASA), and I was detailed as his technical

assistant.

FRIEDMAN THE MAN

My respect and admiration for the man for

whom I worked increased with every contact and

Page 185

The Legendary William F. Friedman

LAMBROS D. CALLMAHOS
discussion. At first, our relationship was most formal – “Captain C.” and “Mr. Friedman.” Later on it

became “Cal” and finally “Lambros,” but it was

always “Mr. Friedman.” It took Mark Rhoads, his

administrative assistant and colleague of long

standing, a dozen years to call him “Bill”; and Mr.

Friedman was “Bill” only to his friend and respected colleague Brigadier John H. Tiltman, to the

Chief, ASA, and to a handful of senior military 

officers. To the rest, including his closest associates

of the early ‘30s – Solomon Kullback, Frank

Rowlett, and Abraham Sinkov – he was always 

“Mr. Friedman” – even when they were not in his

presence.

I used to speak of him affectionately as “Uncle

Willie” when not within earshot; the sobriquet

caught on and became widespread at Arlington

Hall, and when he learned of the appellation he was

amused. But once, at an Agency party when the two

of us were by ourselves at the canape table and I

called him “Uncle Willie,” I was made aware of my

impertinence. One simply did not take liberties

with WFF.

Mr. Friedman’s desk in his private office in

Headquarters Building at Arlington Hall was about

fifteen feet from mine in the outer office, but much

of our daily contact was in the form of written

notes. I would screen incoming technical papers

and pass on to him those meriting his personal

attention, with a buck slip on top. He would buck

notes back and forth to me, sometimes exchanging

six or seven notes: Mr. Friedman was fond of written records. Since he did superior work himself, he

expected that all those around him would also do

the same, without question. Compliments were

hard to come by. Once, when I did something evidently worthy of particular notice, he wrote on a

note, “Capt. C. – Good!” I poked my head into his

door and inquired solicitously, “Are you ill, Mr.

Friedman?” “No, why?” he replied. I answered,

“You wrote ‘Good’ on your note.” He laughed, and

from then on he allowed himself an occasional

complimentary adjective that greatly added to the

psychic income that was already mine in having the

privilege of working with him. On another occasion

when I outlined what I thought was an especially

good idea, he listened patiently and, when I had finished, said: “That’s fine. I have a patent on that.” At

another time I received his compliments on an original procedure, until I found out a couple of weeks

later that he had already written about it and had

forgotten about it, so I embarrassedly brought it to

his attention. Homerus nutat.

As an army captain, I was very proud to work

for Mr. Friedman, in view of what he had done and

was doing for his country. Always a stickler for le

mot juste, he abhorred imprecise or inelegant language. Once, when I did not use the term “repetition” when he felt that I should have, he said:

“Don’t ever use ‘repeat’ as a noun again!” When I

found that the dictionary recognized the use of

“repeat” as a noun, I was a bit miffed, but I swallowed my pride and was very careful in the future

how I expressed myself to the Great One. On another occasion, when he came across the cover name

ICKY in a technical report he blew his top, exclaiming that this word made him puke [sic].

Mr. Friedman had complete faith in his subordinates – otherwise, he felt, they wouldn’t be working for him. He took for granted that I knew all that

was necessary to know about cryptanalysis – a most

flattering compliment, but unrealistic. One day a

paper came through on a most complicated and

abstruse phase of a technical matter about which I

comprehended not even the title. I shrugged my

shoulders and bucked the paper to him, feeling that

this certainly was one matter with which I should

have absolutely nothing to do, especially since three

leading technicians of the Agency differed among

themselves as to the merits of technical points. To

my horror, Mr. Friedman bucked the paper back to

me with a note, “Captain C.: please study and prepare comments for me.” I was frantic. But I spent

the next three days working eighteen hours a day,

did some historical research on the problem, spoke

with technicians on the project, fortunately came

up with a refutation of points held by the author of

the paper, discovered a new approach, and drafted

Page 186
a substantive reply worthy of William Friedman. It

wasn’t until many years later that I told Mr.

Friedman how that one paper made me sweat

blood – he of course had blithely assumed that I

was versed in all matters of cryptanalysis, including

that one.

When I was first assigned to Mr. Friedman’s

office, I was living in a room on the third floor of

Headquarters Building: my family was still in New

Jersey, where they had been while I was overseas,

as apartments were almost impossible to obtain in

the immediate postwar years in Washington. I was

working two shifts: the day shift for Mr. Friedman,

the swing shift for me. With Mr. Friedman’s knowledge and permission, I went systematically through

all his files, reading hundreds of technical reports

over a period of many months, trying to remember

all I could in this unparalleled opportunity for

acquiring a comprehensive technical education.

The effort paid off when my boss asked me about

things I had already digested and on which I was

now knowledgeable: my ready answers strengthened his conviction of the extent of my cryptanalytic knowledge. Mr. Friedman was meticulous in his

work habits, whether on staff policy papers or in

technical exposition. He would first think out the

problem or situation in broad outlines, and then

would map out points a, b, c, . . . .n in logical progression, with clarity of exposition and the greatest

attention to detail. He wasted but little time or

motion, and especially on technical matters he

knew instinctively when he was on the wrong track

– a splendid attribute for any cryptanalyst. He had

immense drive, and knew how to organize his colleagues for the most effective teamwork to achieve

the maximum efficiency of effort.

In his technical writings, Mr. Friedman was a

man of punctilio. In the first book that he wrote for

the U.S. government, Elements of Cryptanalysis, a

little gem of 157 pages published in May 1923 by the

Office of the Chief Signal Officer, he brought order

into the chaos of cryptologic exposition of previous

authors in the public domain. This work he expanded in the late 1930s into his classic textbooks,

Military Cryptanalysis, Parts I-IV. He had a flair

for the dramatic, as witnessed by the following

extract from one of his technical papers2 in which

he not only had two successive sentences ending

with exclamation marks, but threw in some italics

for good measure:

A set of fifty test messages, each twentyfive letters in length and beginning at the

same initial enciphering juxtaposition,

was submitted by Mr. Burdick. By superimposing the messages the writer solved

them and completely reconstructed both

basic alphabets by applying and extending the principles of indirect symmetry of

position that were discovered by Mr.

Burdick himself! It is not often that a

cryptanalyst unknowingly discovers the

very weapon that deals the deathblow to

his own brainchild!

It’s too bad that not many tellers of cryptologic tales

emulate the patterns set by the Master.

On a couple of occasions in the early 1950s, I

received brief handwritten notes from Mr.

Friedman asking me to do something or other

which I felt really wasn’t necessary. So I just let the

notes go by, hoping he would forget about them.

Several weeks later, he asked me what I had done

about the items, and I lost no time in doing what he

asked me to do in the first place, marvelling at his

memory. Much later I found out his secret: he kept

carbon copies of everything he wrote in longhand,

no matter how brief! I was shocked: I never really

got over what I considered to be a very unethical

and underhanded way of doing business. After he

retired in 1955, I was bold enough to tell him of my

feelings, and he got a kick out of my reaction to his

craftiness.

Mr. Friedman had a fine sense of humor, but his

was a passive one, enjoying others’ overt actions.

He was particularly fond of me and enjoyed my

company, considering me a character (this proves

that Mr. Friedman was not always infallible in his

Page 187
judgment), and after he retired and we became fast

friends I was able to pull his leg (in private, of

course!) and treat him more irreverently than anyone else dared. Only once, however, did I overstep

my bounds. He never liked to think of eventual

death, and I had the temerity to suggest to him that

after he passed on to the Great Beyond he should

will his body to NSA so we could stuff him and prop

him up in a corner of the cafeteria. Needless to say,

that went over like a lead balloon.

I used to smoke Roi Tan Golfers, little cigars

about 3 1/2” long. Once in the late ‘50s when I was

visiting Mr. Friedman at his home, he asked, “Why

do you smoke those little cigars?” I replied that I

liked their taste and convenient size. “You know,

somebody might think that’s an affectation,” he

said, as he dipped into his engraved silver snuff box.

I asked him if I might try some of his snuff, gingerly placed some in each nostril, sneezed, blew my

nose (into a handkerchief), and found that it was a

pleasant sensation. So for the next dozen years I

gave up smoking in favor of snuff, and I collected

over 170 varieties from all over the world. What

bothered me, though, was that as soon as I had gotten hooked on snuff, he quit. Now that’s no way for

a pusher to act, I thought. (I myself quit in 1971, one

less vice in my repertoire.)

In the years after his retirement, Mr. Friedman

used to call me several times a week. The phone

would ring, I’d pick up the receiver, and a voice

would say “Cal?” I would reply, “Yes, Mr.

Friedman.” At other times the voice would say,

“Professor?” and again I would reply, “Yes, Mr.

Friedman.” Once, however, when I picked up the

phone and all I heard was someone clearing his

throat, I said, “Yes, Mr. Friedman,” and he was too

startled for words: he never got over it. How could

I explain to him that a musician’s ear could recognize the “harrumph” of a particular speaker? This is

closely correlated with linguistic talent, and Mr.

Friedman was not conversant with any language

other than English; but that did not prevent him

from achieving significant successes with cipher

messages in Japanese and other languages.

Mr. Friedman often relived his earlier years,

and he found mine a willing ear as he recounted his

early triumphs and successes. His career was rich in

experiences, richer perhaps than anyone in the

cryptologic world has had, before or since. I would

ask him about technical points, and he would outline for me a particular solution that he had accomplished years before. I sincerely regret not taking

notes of our discussions, for somebody should have

been a Boswell to his Johnson.

During the last several years of his life, I was

Mr. Friedman’s close confidant. There were times

when he felt depressed, that the world was no

damned good, and that he really hadn’t done anything to make it a better place to live in. Of course I

vehemently disagreed, pointing out all he had done

for his country (as if he didn’t know!). He often

asked my advice on various matters, technical and

nontechnical, so I proposed that he retain me as an

advisor for a dollar a year: after all, he didn’t have

to take my advice, but if he paid me he would

respect me more. Several months ago Mrs.

Friedman found among her husband’s effects a

note reading “Pay Cal a dollar a year.”

Mr. Friedman always had a very inquiring and

discerning mind. He was a bibliophile, a gentleman, and a true scholar. He was astute in judging

character, and he could read his adversaries like a

book. He was, as I have indicated before, very sensitive on interpersonal relationships, and he relished the friendship and acquaintance with high

persons in the government and in industry, both

here and abroad. He was an elegant dresser, prided

himself on his ability as a ballroom dancer, and was

a golfer of no mean stature.

FRIEDMAN THE CRYPTOLOGIST

William Friedman was blessed by phenomenal

luck throughout his entire career as a cryptanalyst

– everything he touched turned to plain text, a sort

of latter-day Midas. But since this luck was so consistent it couldn’t have been luck; on the other

hand, it must have been luck. He was a young man

Page 188
when he started, and therefore had the courage of

his convictions and the boldness of youth. He started young enough not to be scared of the magnitude

of the problems facing him: had he been a Ph.D.

with three or four years’ postgraduate training, he

could have been ruined. His definition of a cryptogram was simply a secret message that was meant

to be solved, just that. Time and again he shouldn’t

have been able to solve a particular message or a

cryptosystem, but he did: the odds were against

him, but luck was with him. That is, luck tempered

by logical insight and remarkable intuition. Some of

his early solutions may seem almost childish by

present-day standards, but William Friedman was

the first child of any age to arrive at those solutions.

He wasn’t disturbed by the apparent odds

against him: after all, even a simple substitution

cipher in a literal system involves 26! (= 4.03 X

1026) possible alphabets, and it can be demonstrated that, if there existed a computer capable of 

testing one million alphabets per second, even if 

we have a thousand of these computers it would

take over one billion years to run the gamut of 

all the alphabets. He might have countered that,

since there is a .5 probability of success halfway

through, he would expect results after only 500 

million years.

There is no least common denominator of what

makes a brilliant cryptanalyst: he can be a mathematician, but he may just as likely be an archaeologist, a chemist, a biologist, a musician, a gambler, a

painter, or a cook – in short, just about anything.

Now Mr. Friedman’s background in mathematics

was slight: college freshman mathematics. Even if

he computed odds incorrectly, it didn’t make any

difference because he would forge ahead in his

blissful ignorance and solve the problem anyway.

On several occasions he told me that if he had had

more of a mathematical background, he might not

have been able to solve some of the things he did.

Mr. Friedman may not have been a mathematician,

but he had superb mathematical feeling and

insight, inventing techniques that were missed by

mathematicians working on the problem. A classic

example of his innovative abilities was in his solutions of the Hebern machine in 1923, the first solution in history of a wired-rotor cipher machine. He

postulated that there were ninety-one billion alphabets involved when there were really only forty-five

billion, and – in spite of his modest mathematical

background – originated an important theory of

coincidence and, with only ten messages, arrived at

a solution of the machine.

I told Mr. Friedman of an anecdote I used to

relate to the students in my classes as an example of

his lack of mathematical profundity, but stressing

to them that this had absolutely no bearing on his

prowess as a cryptologist. In his 1923 work,

Elements of Cryptanalysis, he gave on p.105 three

72-letter transposition messages with the following

footnote:

As an example of a most remarkable coincidence, note the appearance of the word

CIPHER in the cipher text of the third message. Theoretically, such an event will happen, as a result of chance, once in 266 (=

308,916,776) times. The word CIPHER

does not appear in the plaintext message at

all!

What Mr. Friedman did not note was (1) that

the cipher texts did not approach the appearance of

random text but were composed of a good assortment of letters as found in English plain text; (2)

that, in calculating probabilities, he did not take

into account in which message, nor at what position

in that message, the word should be; and (3) that he

was not even looking for that particular word in the

first place. Mr. Friedman always got a charge when

I related this anecdote. To offset this mathematical

lapse, though, it must be remembered that his

paper written in 1920, The Index of Coincidence

and Its Applications in Cryptography, was the pioneer paper in cryptomathematics.

As a simple example of the perpetual luck which

plagued him, a case may be cited of a 443-letter

cryptogram submitted to the War Department for

Page 189
solution.3 The cipher text factored to ten alphabets,

and Mr. Friedman unerringly selected equivalents

for plaintext E in some of the alphabets when the

next highest cipher values were only one or two tallies less than the supposed E plain, and he derived

five other values scattered sporadically in the cipher

message. At this point he focused his attention on

the beginning of the text, which he had thus far

deciphered as _ _TTH_ _ _ _. It must begin, said

Friedman, with the words BUT THOUGH – and it

did. Well, I assure you, dear reader, that this will be

the first and last time you will ever encounter a

message beginning with BUT THOUGH: the

Friedman luck paid off again.

Another unbelievable piece of luck occurred in

1917 when Mr. Friedman was at Riverbank

Laboratories in Geneva, Illinois, where he was

employed as a geneticist mating fruit flies (or

rather, helping them to mate). The British knew of

a geared disk cipher device invented much earlier

by Sir Charles Wheatstone that was regarded as

absolutely indecipherable if the sequences for both

plain and cipher components were unknown. The

British did not dare use it earlier in World War I,

because if the Germans captured it they too would

have the indecipherable cipher. But now, since the

United States had entered the war, the British

decided to use this device for joint U.S.-British

communications since its indecipherability was

acknowledged by both London and Washington.

But somebody in Washington suggested that perhaps it might be wise to have the device tested by

William Friedman at the Riverbanks Laboratories,

which were operated by a wealthy eccentric named

Colonel George Fabyan, who had a quasi-official

relationship with the government.4 Accordingly,

five very short test messages – a most unrealistic

test – were sent to Friedman, and by a process that

remains a mystery to this day he was able to

scrounge out from the cipher texts the sequence for

the cipher component, a numerical-key columnar

transposition-mixed sequence based on the word

CIPHER. But now he was stumped, since he didn’t

quite know what to do next (it wasn’t until 1923 that

he discovered the principle of reduction to monoalphabetic terms, which would have made the problem a very simple one). But he called in one member of his staff, his wife Elizebeth, told her to give

him the first word that occurred to her. He said

“cipher,” and she replied “machine.” Sure enough,

the plain component was a numerical-key columnar transposition-mixed sequence based on

MACHINE. And one of the messages read, 

“This cipher is absolutely undecipherable.” The

solution went back to the British and, although

11,000 of the devices had been manufactured, they

were never used.

Mr. Friedman returned to Riverbank

Laboratories after the war: he had been in France as

a member of the Code and Cipher Solving Section,

G2 General Headquarters, American Expeditionary

Forces. At Riverbank occurred a third example of

how he was hounded by incredible luck. The AT&T

Corporation had devised a very complicated cipher

teleprinter, adjudged to be beyond the realm of

solvability. But though (there, I did it!) the system

was good indeed, there was still a Friedman to be

reckoned with. Accordingly, a set of 150 cipher

tapes was dispatched to Riverbank, and for six

weeks, sometimes working twelve hours a day,

Friedman and his staff of six studied the traffic. His

staff was disheartened: this was the first time 

they had spent such a length of time on a system

without solving it, and they wanted to quit.

Friedman, though, was sure that his methods were

correct — therefore was it not possible that either

he or one of his assistants had made an error in

transcribing the punched tapes into characters on

paper? He asked them to hang on for one more

week to review their work. Sure enough, in checking, he discovered that one character had indeed

been omitted accidentally in transcribing one of the

tapes – but that character was at a very crucial

point. Within minutes, he made an entry into the

plain text, and the system was solved.5 To make the

solution even more convincing, a punched tape was

laboriously prepared by hand and sent to

Washington with the proper indicators: when the

tape was set on their machine and the message

read, it gave the proof of the solution.

Page 190
All of these wonders William Friedman accomplished without the benefit of any machine aids

whatsoever. In fact, during Riverbank days he

invented the very first mechanical cryptanalytic aid

made in the U.S. It was called the “polyalphabetic

wheel” and consisted of the twenty-six letters A

through Z on a rubber-faced wheel that, when

inked, could be used for running down the alphabet

from a predesignated initial letter. The device was

improved by assembling ten such wheels together

so that the plain-component sequences could be

completed on ten letters at a time, but this required

the services of a muscular cryptanalyst to bear

down on the roller.

On January 1, 1921, Mr. Friedman began a sixmonth contract with the U.S. Army Signal Corps to

prepare cryptographic systems, and the contract

was renewed for another six months. In 1922 he

was hired as the sole cryptanalyst in the Signal

Corps, with a cauliflower-eared ex-professional

boxer as a secretary. Until April 1, 1930, the entire

cryptologic organization of the U.S. Army consisted

of only Mr. Friedman and one clerk typist. During

that first week in April, the Signal Intelligence

Section was expanded by the addition of three

young high school mathematics teachers recruited

by Mr. Friedman as junior cryptanalysts: Solomon

Kullback, Frank Rowlett, and Abraham Sinkov,

who were to remain in cryptologic work, making

notable contributions for over three decades and

rising to high positions in NSA and its predecessor

organizations.6

An amusing story is connected with a challenge

message submitted to the Signal Corps in 1933 by a

New York lawyer representing his client, a poor

devil who had bought, for $100,000, the North

American rights to a cipher machine invented by

Alexander von Kryha of Germany. The machine

was touted by the inventor as absolutely indecipherable, and a German mathematician had

demonstrated that the number of ways in which a

message could be enciphered was 2.29 X 1082, a figure 100 million times as large as the number of

atoms in the universe. Friedman had studied the

machine earlier, and had demolished it along with

everything he studied. After an exchange of correspondence with the lawyer, Friedman told his superior that it might be a profitable training exercise

for his subordinates if the 200-word challenge were

accepted. Accordingly, the lawyer prepared a message enciphered on the machine, the alphabets and

initial setting being secret. The message, in triplicate as requested, was on February 24, and datestamped “Feb 24 AM 11:12,” with the notation in

Friedman’s handwriting, “Commenced work.

W.F.F .” And then over the date-time stamp “Feb

24 PM 2:43,” was the cryptic notation, “Solved.

W.F.F.” Elapsed time: 3 hours and 31 minutes, less

50 minutes for lunch – 2 hours and 41 minutes! A

letter with the decipherment and the keys was sent

to the lawyer that afternoon. This solution in 2

hours and 41 minutes is remarkable not only

because of the absence of any machine aids at that

time,7 but particularly so for the light it throws on

Mr. Friedman’s direction and organization of the

cryptologic effort of his three assistants. As a result

of this solution, the Signal Intelligence Section

gained renewed respect and – far more important –

recognition at the highest army levels and increased

fiscal support.8

Cryptologic literature in the 1930s was woefully

inadequate.9 Mr. Friedman therefore embarked on

a program of translating foreign works in the public domain, and of publishing technical reports of

the solution of cryptosystems studied, in order to

begin collecting a body of literature for training

cryptanalysts in the years to come. As a consequence, during an eight-year period in the 1930s

the members of the Signal Intelligence Section

(numbering not more than eight at any one time,

including student officers) wrote over sixteen books

of expository technical works in cryptanalysis.10

Friedman systematized the art, and unfolded the

science in his classic four volumes, Military

Cryptanalysis, Parts I-IV. When Kullback,

Rowlett, and Sinkov were recruited, they spent

their first two years with Mr. Friedman in a course

of study, consisting of a series of cryptanalytic problems prepared by the latter; the textbook was

Page 191
Elements of Cryptanalysis, then the finest work

extant. In 1931 1st Lieutenant Mark Rhoads was

assigned to Mr. Friedman for one year to learn all

there was to know about cryptography and cryptanalysis. Towards the end of his year, Lieutenant

Rhoads wrote a memo to the Chief Signal Officer

saying that one year was insufficient to learn all

there was to know about cryptology: it would take

two years. Consequently, Rhoads was kept on for a

second year and became the instructor for 1st

Lieutenant W. Preston Corderman, who was

assigned for a two-year tour. The Signal

Intelligence School was formally established, and

Lieutenant Corderman (later to become Chief,

Army Security Agency) was the instructor for the

next student, and so on for a number of student

bodies consisting of two each. Thus was established

the groundwork of scientific cryptanalytic training.

Friedman studied many proposals for cryptographic systems, embracing both manual and

machine methods, demolishing everything that

came his way. Good cryptographic ideas were hard

to come by, as requirements were stiff and standards high. One machine that was studied, the

IT&T cipher machine with ten large cam wheels for

teleprinter encipherment, had a period of 8.65 X

1014: the inventor and his sponsors claimed that

cryptograms produced by the machine were practically, if not absolutely, indecipherable without the

key. It took almost four years to construct the

machine, at a cost of approximately $100,000 – but

it took Friedman and his staff less than three hours

to break it. In another case, an ingenious machine

fractionated a plaintext letter into two parts, subjected these fractional parts to a complex substitution, and finally recombined the parts to produce a

single cipher letter: this was a brilliant idea that did

not long withstand Friedman’s scrutiny. In addition

to his ability to destroy everyone else’s ciphers,

Friedman was able to invent a number of cryptographic systems for his country that would withstand sophisticated attack by enemy cryptanalysts.

For his inventions Congress in 1956 awarded him

$100,000 in compensation for profits he might

have realized if the patents had not been held secret

by the government.

Because of Mr. Friedman’s foresight and pioneering efforts in cryptanalysis, cryptanalytic training, data processing machine utilization, and cryptanalytic organization, the U.S. Army was fully prepared to meet the cryptologic challenges of World

War II. Friedman took part in all these aspects during the war and continued to make notable contributions. After the war a most spectacular role of

cryptanalysis was revealed in the hearings held by

the joint congressional committee on the investigation of the Pearl Harbor attack. At that time it was

made public that shortly before the war the United

States, in a brilliant stroke of cryptanalysis, had

been able to reconstruct the Japanese cipher

machine which was used for the highest-level diplomatic communications, enabling this traffic to be

read throughout the war. The successful solution of

this machine, known by its cover name as the PURPLE machine, represented eighteen months of

intensive study by a group of U.S. Army cryptanalysts under the direction of William F. Friedman.

Mr. Friedman continued after the war as

Director, Communications Research, under whom

I was privileged to work as an army officer. With

the establishment of the Armed Forces Security

Agency in 1949, he became Chief of the Technical

Division, and I was once again working for him, but

this time in civilian clothes. In 1952 the National

Security Agency was created; he was now Technical

Consultant to the Director, and two years later was

named Special Assistant to the Director, the post he

held until his retirement in 1955, after over thirtyfive years of service with United States cryptologic

activities.

EPILOGUE

His inventions and many achievements won for

Mr. Friedman the nation’s highest awards and a

reputation as one of the world’s leading cryptologists. In 1944 he was presented the War

Department’s highest decoration, the Exceptional

Page 192
Civilian Service Award; in 1946 he was awarded the

Presidential Medal for Merit; and in 1955 Mr. Allen

Dulles, then Director of Central Intelligence, presented him the National Security Medal, the country’s highest award for contributions to the national security. He was the author of many classified

publications and training texts, of articles in scholarly journals, and of the articles on cryptology in the

1927 and 1954 editions of the Encyclopaedia

Britannica. With his wife (who was for years a cryptologist with the Treasury Department), he wrote

the book The Shakespearean Ciphers Examined,

for which they were awarded the Folger

Shakespeare Literary Prize and the Fifth Annual

Award of the American Shakespeare Festival

Theater and Academy.

On Sunday, November 2, 1969, William

Frederick Friedman died quietly at his home in

Washington, D.C., and was buried with full military

honors in Arlington Cemetery. The legendary figure

is with us still – in the works he left behind, in the

science he created, and in the inspiration he

bequeathed to his colleagues and friends.

NOTES

1. The way I got into the Cryptographic School was

no accident. I paid a courtesy call on my New York City

draft board complete with waxed mustache, goatee, big

black hat, Chesterfield coat, spats, gloves, and cane, like

something out of a Dumas novel. When I showed them

the list of 40-some works on cryptology I had read in

preparation for eventual military service, the board sent

me to Army Headquarters in Church Street, and they in

turn sent me to Governor’s Island, where G-2 arranged

for what I thought was to be Army service of one year in

the Cryptographic School.

2. .”The Principles of Indirect Symmetry of Position

in Secondary Alphabets and Their Application in the

Solution of Poly alphabetic Substitution Ciphers,” Office

of the Chief Signal Officer, Washington, 1935.

3. L.D. Callimahos and W.F. Friedman, Military

Cryptanalytics, Part II, 108-113.

4. Fabyan’s title was an honorary colonelcy conferred by the governor of Illinois for Fabyan’s participation as member of the Peace Commission that negotiated the Treaty of Portsmouth, which terminated the

Russo-Japanese War in 1905. One of Fabyan’s fields of

interest was cryptography, and in the latter part of 1916

he established a Department of Ciphers at Riverbank,

first headed by Miss Elizebeth Smith and later by Mr.

Friedman, who took over both the Department and Miss

Smith. The Department of Ciphers conducted cryptanalytic work for the State, War, Navy, and Justice

Departments, since at the time none of these organizations had any cryptanalytic units whatsoever until the

Army established a unit (under Herbert O. Yardley) in

the latter part of 1917.

5. For Mr. Friedman’s own account of this solution,

see “Can Cryptologic History Repeat Itself?” NSA

Technical Journal, Vol. XVIII, No.3, Summer 1973.

6. In selecting his personnel, Mr. Friedman picked

the three persons from the civil service list who had

made the highest scores on the mathematics examination.

7. It was not until 1936, after Mr. Friedman’s continued insistence, that the Army obtained its first IBM data

processing machines for cryptologic purposes.

8. For the story of this solution in detail, see L.D.

Callimahos, “Q.E.D. – 2 Hours, 41 Minutes,” NSA

Technical Journal, Vol. XVIII, No.4, Fall 1973..

9. Cryptologic literature in the 1970s is woefully

inadequate.

10. In a memorandum that I sent on June 14, 1960,

to the Director of Training, NSA, I pointed out that by

comparison NSA should have published 3,200 books in

the last eight years, but that the true figure was less than

sixteen, or one-half of one percent of the productivity of

the early Army effort.

Page 193
Page 194

Lambros Callimahos won world renown as a flute virtuoso

before serving in the Army cryptologic unit in World War II.

He was technical assistant to Mr. Friedman, with whom he collaborated on the classic texts, Military Cryptanalytics, Parts III. He was the author of many monographs, studies, and articles, including one on cryptology in the Encyclopaedia

Britannica. For over twenty years Mr. Callimahos taught the

Agency’s most advanced course in cryptanalysis, Intensive

Study Program in General Cryptanalysis. At the time of his

death in October 1977, Mr. Callimahos had taught 32 classes

and over 270 students.
[Editor’s Note: This article, published in the

Smithsonian magazine of June 1987, is republished

with the permission of the author.]

Toward the end of World War I, the British

Army began manufacturing thousands of small

cipher machines, “Pletts Cryptographs,” for use by

the Allied forces. The British asked the American

forces to use them as well. No one in the French,

British, or American military had been able to

break the ciphers; the machine had a mechanism

that regularly altered the ciphering scheme, so the

first a might be turned into an f and the next a into

an r.

Just to be sure that it was safe from enemy

codebreakers, the American military passed it on to

a remarkable husband-and-wife team in Illinois for

testing. William and Elizebeth Friedman received a

package with five telegram-length messages. It took

them all of three hours to break the lot, after which

they returned them to London, solved. The first of

the five messages read: “This cipher is absolutely

indecipherable.”

Few ciphers were ever indecipherable to the

Friedmans. By the end of his life, William Friedman

was recognized as the greatest maker and breaker

of secret messages in history – the Harry Houdini

of codes and ciphers. Repeatedly, he accepted challenges to solve “unbreakable” ciphers, and succeeded. The papers he wrote brought cryptology, an

ancient skill as obscure as witchcraft, into the scientific age. The team he trained and supervised

broke into Japan’s highest diplomatic cipher just

before World War II; not only did the group penetrate the secret, it built a deciphering machine that

worked as well as Japan’s cipher machine.

Elizebeth Friedman provided exceptional assistance to the U.S. Coast Guard and Navy, unraveling

secret messages from rumrunners during

Prohibition, narcotics traffickers during the 1930s,

and enemy agents during wartime. True to the

shadowy world of intelligence work, the pair

shunned publicity and avoided discussing their

work – even with each other.

Neither had planned a career of codebreaking.

In keeping with the strangeness of their profession,

it all began at a peculiar place called Riverbank

Laboratories. The Riverbank estate, located on the

Fox River in a small suburb west of Chicago, was

the magnificent hobby of Colonel George Fabyan,

an eccentric millionaire who had retired from cotton trading early in the century. Here, on 600 wellkept acres, Fabyan’s stable of hired scientists pursued whatever he found interesting or worthwhile,

from sound waves to cryptology to plant genetics.

In the evenings, they enjoyed the genteel life of the

“minor idle rich,” in Elizebeth’s words. Other

employees tended his greenhouses, livestockbreeding operation, Dutch windmill, Japanese garden, and caged vegetarian bears. A monkey and

other pets had free access to Fabyan’s house, which

was also notable for its furniture hung from the

ceiling by chains.

Page 195

Breaking Codes Was This Couple’s

Lifetime Career

JAMES R. CHILES

Eccentric millionaire George

Fabyan built up

a brain trust at

Riverbank.

[Photo as in file]
Fabyan, a large and loud man with iron-gray

hair who wore frayed formal clothes in the city and

a sort of horseman’s outfit in the country, “had

great natural gifts of energy and dynamism,” the

Friedmans wrote later. “He also had the trick of

parroting other people’s jargon; his conversation

was usually impressive – superficially, anyway.”

In the spring of 1915, Fabyan went hunting for a

geneticist to improve crop strains. A professor at

Cornell suggested William Friedman, a graduate

student in genetics. Friedman, who had been born

to a Russian Jewish family in 1891 and brought to

America as an infant, was preparing for a future in

biology. When Fabyan offered him the job,

Friedman asked him what he raised on his estate. “I

raise hell,” Fabyan replied. Friedman signed on at a

hundred dollars a month as head of Riverbank’s

Department of Genetics and began work the following September, taking up quarters in an upper floor

of the windmill. In a short time Fabyan had him

planting oats by the light of the moon, to see

whether the phases made any difference.

The other half of the Friedman team, Elizebeth

Smith, graduated from Hillsdale College in

Michigan in 1915 with an English degree, and a year

later sought work in Chicago. At the Newberry

Library, a staff member mentioned to her that a

George Fabyan was looking for somebody to study

Shakespeare and offered to call him at his Chicago

office. Fabyan arrived in his chauffeured limousine

and insisted that Elizebeth come to the estate

immediately. “He was the kind of man who did not

take ‘no’ for an answer,” she would reminisce. That

evening she met Elizabeth Wells Gallup, a woman

who had convinced Fabyan that Francis Bacon was

the real author of Shakespeare’s plays and sonnets

and that Bacon had hidden a number of secret messages inside the original printed copies. Elizebeth

agreed to assist Mrs. Gallup in this unusual project.

And so began the Friedmans’ long involvement

in the esoteric world of ciphers and codes. For most

of the rest of us, here’s the difference between the

two: in a typical cipher (such as the Pletts

Cryptograph solved by the Friedmans in 1918) each

letter of the original message is changed into another letter or symbol according to some orderly

scheme. To decipher the message, it helps to know

that e is the most frequently used letter in English.

With additional knowledge of the language and

guesses based on the context of the emerging message, the rest of the alphabet follows.

Most ciphers, however, are vastly more complicated than a single substitution: e will be represented by different symbols at different points in the

message. A basic way to accomplish this is to assign

each letter of the alphabet a number: a is 1, b is 2,

and so on. Then we add a key, a regularly repeating

group of characters or words superimposed onto

the message. Say we want to send the word “trouble,” and our key is “fast.” It works like this:

Message:

20(T) 18(R) 15(0) 21(U) 2(B) 12(L) 5(E)

Key:

6(F) 1(A) 19(5) 20(T) 6(F) 1(A) 19(5)

Total them:

26 19 34 41 8 13 24 

. . . and you have a cipher that your nosiest neighbor probably couldn’t break. Your cousin on the

other end will know the key, subtract it, and then

distill the message. But it wouldn’t even make

lunchtime recreation for a cryptologist, who would

aim a barrage of statistics at it and solve it in minutes.

A code is different. A typical code takes ideas in

the message – words or even whole phrases – and

changes them into something else, usually groups

of numbers taken out of a codebook resembling a

small dictionary. To compose a coded message, the

sender first writes what he intends to say (“Attack is

imminent”) and then looks up the words in his code

Page 196
book. “Attack” is 1140, and “imminent” is 4539.

And that’s his message: 11404539. To further confound the enemy, the sender might scramble the

signal by using a key to encipher those numbers, by

switching around the order, or both. The receiver

must have an identical code book and know anything extra the sender has done to scramble the

number groups.

Codes and ciphers go back many centuries.

Ancient Greek commanders scrambled messages

by wrapping a strip of parchment or leather around

a tapered staff in a tight spiral and writing their

message down the length of the staff; unwound, the

strip displayed a jumble of illegible letter fragments. A few centuries later, Julius Caesar wrote to

associates in a simple cipher that took each letter of

the message and substituted the letter three places

farther down in the alphabet. Islamic people were

the first to figure out how to attack ciphers in an

organized way. During the Renaissance many

European countries began setting up full-time

codebreaking bureaus, called black chambers, to try

to read each other’s messages.

In 1623 Francis Bacon contributed a new kind

of cipher to this busy scene, one that used only the

letters a and b to represent the entire alphabet. In

the table he set out, aaaaa stood for A, aaaab for B,

aaaba for C, and so on. He called it the biliteral

alphabet, and described how it could be disguised

in an ordinary paragraph by using two different

type-faces: one typeface representing a, and the

other b.

Which brings us to Elizabeth Wells Gallup’s

Bacon-as-Shakespeare theory. It rested on two

piers: Bacon had indeed invented the biliteral

cipher, and the original printed folios of

Shakespeare’s plays employed an odd variety of

typefaces.

Mrs. Gallup believed herself able to take printed lines from the plays and identify each character

as either an a or a b typeface. Consulting the table

that Bacon had published in 1623, she transformed

each group of five a’s and b’s into a letter of the

alphabet. The revelations she concocted were voluminous – one-fifth the length of the plays themselves – and sensational. Bacon, she claimed, not

only wrote the plays but also was an illegitimate son

of Queen Elizabeth I and the rightful heir to the

throne. She convinced Fabyan to spend thousands

of dollars digging holes around London, hunting for

buried manuscripts. (Decades later, the Friedmans

presented evidence that demolished the hiddenmessage theory. The peculiar typefaces were due to

the economical habits of English printers, who preferred to repair old type rather than replace it.)

William Friedman spent time on the Bacon

project as a photographer, taking close-up pictures

of typefaces. Then, over the winter of 1916-17, with

the approach of war, he turned over his genetics

work to an assistant and joined Elizebeth in studying everything they could find on secret writings.

Not much was available: the American literature,

for example, consisted of a couple of short works by

military men, and two articles and a story by Edgar

Allan Poe. “We had a lot of pioneering to do,”

Elizebeth wrote later. “Literary ciphers may give

you the swing of the thing, but they are in no sense

scientific. There were no precedents for us to follow.” In May 1917 the two married.

Meanwhile, Fabyan was bringing in coded

diplomatic messages from unfriendly powers; he

had offered his services free to the government,

which had accepted. For almost a year, until the

creation of the Army’s Cipher Bureau, Riverbank

was the only organization in the country capable of

working out secret messages.

Among the most interesting problems to arrive

at the large cottage where the Riverbank codebreakers worked were the cases involving the

Hindu plotters. The first case was delivered personally by an official of Scotland Yard, who carried an

attaché case packed with dozens of intercepted letters. For several years the Germans had been

encouraging the aspirations of independence held

by Indian citizens, on the theory that any trouble

Page 197
Indian radicals could stir up would siphon British

strength from the war. Some of these radicals lived

in the United States, and they had been passing

cryptic messages around regarding arms shipments

and internal politics.

One of the Hindu systems the couple broke into

was a code that used numbers to indicate words

and letters from a book that both sender and receiver had available. The cryptic number groups came

in clusters of three, and the middle section always

contained a 1 or a 2; that indicated a two-column

page, probably a dictionary. The frequent use of

some number groups indicated certain common

words like “the” and “of.” The first break was 99-2-

14 in the code – page 99, the second column, the

14th word – which they concluded from context

was “you.” That led to 99-2-17, which the couple

guessed was near enough in the dictionary to be

“your.” Eventually they managed to make out nearly every word without having the actual dictionary

at hand. Still, it was important to somehow obtain

the dictionary for the upcoming trial of 135 Hindus

in San Francisco. The Riverbank group polled large

numbers of booksellers without results. Finally,

having arrived in San Francisco to testify at the

trial, William went into a university bookstore in

Berkeley. He described what he was seeking (which

must have been quite interesting in itself), and an

employee dug around and produced the second volume of a German-English dictionary published in

1880. A quick check of the pages showed that this

was, indeed, the book. 

By late 1917 the Army had created its own

Cipher Bureau, and the flow of intercepts to

Riverbank ended. Fabyan, determined to stay in the

center of the action, arranged for the Friedmans to

conduct classes in cryptography for Army officers.

Soon after the classes ended, William accepted

a first lieutenant’s commission in the Army and left

for France. He spent the first five months of the war

with General Pershing’s staff, concentrating on

breaking into the German codebooks. It was

enough time to learn some important things about

how armies employed codes and ciphers in

wartime, and what could go wrong. For example, he

observed that the German messages often began

and ended with ritualized phrases, and that when a

new code or cipher was introduced, the enemy’s

clerks were most likely to make a serious error

(called a “bust” in the trade), exposing the system.

The following spring, William and Elizebeth

returned to Riverbank. There William returned to

the studies he had started before he left for Europe,

which Fabyan issued as individual volumes in his

Riverbank Publications series. In 1920 Friedman

finished No. 22, titled The Index of Coincidence

and Its Applications in Cryptography. This booklet, says David Kahn, author of The Codebreakers,

“must be regarded as the most important single

publication in cryptology. It took the science into a

new world.” Friedman went beyond simple counts

of letter frequency to discover techniques for applying statistical methods to cryptanalysis.

If you take any two lines of English text and

place one above the other, so that each letter lines

up with the one above or below it, there will occasionally be places where the same two letters

appear in a vertical column. Friedman found that,

for English, this coincidence consistently occurs in

6.67 columns out of every 100, or about seven percent of the time. He also found that this rate, the

Index of Coincidence, is unique for each language.

Such information can be very useful to a cryptanalyst with several enciphered messages from the

same source. Usually these ciphers would be created using the same key, but the sender will have

enciphered each message by starting at a different

place in the key, according to some rule previously

arranged between him and the receiver. Using the

Index of Coincidence, the cryptanalyst can place the

messages one above the other and, by sliding them

back and forth, find the right “fit” – an indication

that the key in the top message is vertically aligned

with the same key in all the messages below it. Once

the messages are aligned according to their key, he

can work from message to message knowing that

each letter in a vertical column has been enciphered

Page 198
with the same key letter as all the other letters in

that column.

Shortly after this breakthrough, the Army

offered to employ the Friedmans as civilian “code

experts” for a six-month trial period. With a few

wary glances backward at Fabyan, wondering

whether his tenacious grasp would reach to

Washington, they left Riverbank for good and started military contract work in Washington, D.C.,

early in 1921.

In 1922, the War Department hired William

permanently as chief codebreaker. Over the next

few years he solved several “unbeatable” ciphers

produced by machines. One of these, developed by

Edward Hebern, foretold the hellish complicated

cipher machines that would dominate the next two

decades. It used five movable rotors to scramble

electrical signals between a keyboard and a set of

glow lamps showing the enciphered letters. William

had to determine the ciphering scheme and then

reconstruct much of the internal wiring. “He was

discouraged to the point of blackout,” Elizebeth

said later. “Probably he sat for six weeks before he

thought of a way to attack it. . . It was all resolved in

the end by the Index of Coincidence.”

The Hebern solution was particularly important, says Louis Kruh, coauthor of Machine

Cryptography and Modern Cryptanalysis,

because that machine “introduced a whole new

concept of encipherment. It was the forerunner of

any decent cipher machine between then and

beyond World War II. Some of the report that he

wrote on the solution is still classified today.”

Page 199

(For the solution, see page 201)

The best way to appreciate the codebreaker’s trade is to attack a secret message. The following

cipher uses letter-for-letter substitution, and all punctuation and word spacing have been preserved. You will have to tabulate the cipher letters by how often they occur, and then guess at the

plaintext letters they stand for. The way to do this is to compare the frequency of the cipher letters to the frequency of letters in common English. On average, the most common letter in

English is E,followed by T, 0, A, N, I, R, S, H, D, L, U, C, M, P, F, Y, W, G, B, V, K, J, X, Z and finally Q. Try to identify the most common letters first, then fill in the rest by context.
The latter part of that decade was exciting for

Elizebeth. Her code breaking began in earnest in

1927 as a “special agent” on loan from the

Department of Justice to the Coast Guard, which

was struggling to enforce the Volstead Act against a

flood of smuggled shipborne liquor from the

Bahamas, Canada, and elsewhere.

The rumrunners’ system required radio communications for rendezvous points, warnings, and

prices. It was this encoded and enciphered radio

traffic that Elizebeth attacked. The early messages

were elementary and quick to break. But as time

went on and profits climbed, larger and more

sophisticated syndicates took over the distribution

network, and coding systems became more and

more elaborate. In the first three years she and her

assistants solved 12,000 messages using dozens of

different schemes. In 1934 her decoding, and the

detective work it inspired, cleared up a major diplomatic problem between the United States and

Canada dating to 1929. She proved from old

telegrams that the I’m Alone, a Canadian-flag

schooner shelled and sunk by the Coast Guard in

the Gulf of Mexico, had been secretly owned by an

American smuggling ring.

Elizebeth, now working for the Treasury

Department, was a star witness in a large and

expensive trial in New Orleans of top officials of a

Canadian outfit that controlled most of the liquor

smuggling via the Gulf of Mexico and the Pacific

She deciphered and decoded cryptic radio messages that made prosecution possible.

The Friedman family, which by now included a

son and a daughter, was aware that their mother’s

contact with organized crime had its dangers.

Recalls daughter Barbara Atchison, “I remember

Dad jesting once, when Mother was late getting

home, that she might have been taken for a ride.”

And, in fact, while the I’m Alone case was under

way, agents of the Treasury Department kept her

under constant protection. Elizebeth broke open

the code-ciphers used by narcotics smugglers. Her

contributions to several sensational trials, and the

associated convictions, earned her much unwanted

attention from the press: “U.S. Woman Helps

Smash Drug Ring” and “Key Woman of the T-Men,”

read two headlines.

War came and her work changed again. She

devised a code system for William (Wild Bill)

Donovan as he was organizing the Office of

Strategic Services, and deciphered messages from

German spies in Allied lands.

All this time William had been equally busy, but

his work was well hidden from public view. In 1930

his responsibilities changed abruptly from the

bookish work of composing codes. It was prompted

by the closing of the Black Chamber, a cooperative

codebreaking effort of the State Department and

the Army that had evolved from the Army’s old

Cipher Bureau. The Black Chamber had decoded

messages between Tokyo and the Japanese

embassy, and in early 1929 Herbert Hoover’s new

secretary of state, Henry Stimson, had removed his

department’s funding upon hearing about it. Years

later, in his autobiography, he justified his action by

saying that diplomats should not engage in such

activities because “gentlemen do not read each

other’s mail.” The Army quietly transferred the

activities from the State Department to a new unit

in the War Department, the Signal Intelligence

Page 200

Elizebeth

leaves D.C.

home to testify

against smugglers whose

codes she

cracked.
Service (SIS). Friedman took charge as chief civilian cryptanalyst.

One of William’s principal tasks was to train a

new generation of experts to make and break codes,

because all of the Black Chamber’s personnel had

dispersed. He started in the spring of 1930 with

four spaces. He selected Frank Rowlett, a teacher

from a small town in Virginia; Solomon Kullback

and Abraham Sinkov, mathematicians from New

York City; and John Hurt, the nephew of a congressman and an expert in Japanese.

The new team combed the files of the Black

Chamber for useful information on Japanese cryptology. They read Friedman’s booklets and worked

through problems he concocted. He gave them

assignments such as solving the Hebern cipher

machine. “His teaching was such that we developed

on our own,” recalls Abraham Sinkov. “He just

looked in from time to time to see how we were

doing.”

They operated on slim budgets – bringing their

own pencils and writing on the back of old weather

reports to save paper – but within two years they

had progressed enough for Friedman to present

them with the real thing: encrypted radio communications between Japanese diplomats.

By this time the Japanese knew that America

had been reading secret diplomatic radio traffic. To

protect its highest-level communications, Japan

quickly switched to the new electromechanical

cipher machine, “Angooki Taipu A,” or “Red” to the

Americans. It used a combination of wheels, rings,

and a rotor to scramble clear messages into a complex cipher. In 1935 the Army ordered Friedman’s

group to concentrate on breaking the system; by

1936 they were able to read the messages.

The passion for cryptology spilled over into the

Friedmans’ home life. William created a cipher

game for children called “The Game of Secrecy” and

tried it out on his son, John. He printed holiday

greeting cards with cipher messages.

The most inventive of these pastimes were the

progressive dinner parties hosted by the

Friedmans. They divided their guests – a unique

blend of codebreakers, newspapermen and scientists – into teams, and held the first course at one

restaurant. “While they were eating, the restaurant

owner gave them a piece of paper containing a clue

about the next place to go,” recalls John Friedman.

“They’d go to five or six restaurants. . . The first

team to return home, won a prize.”

William amused his children with enigmatic

behavior. “He would come down to Sunday breakfast with six different ties on,” remembers his

daughter, Barbara, “He had a terrific sense of

humor and whimsy, and women absolutely adored

him.”

Friedman had to leave most of his social life

behind, however, when the Japanese decided to

replace the the Red machine with something much

more secure. Labeled “Purple” by the SIS, the

machine first contributed messages to Japan’s

radio circuits in February 1939. Unlike its predecessors, Purple used a type of switch identical to

those used in automatic telephone exchanges to

accomplish the main work of the encipherment.

While dozens of others did the detailed statistical analysis necessary, William labored alone in his

office on portions of the problem. He worked obsessively. The fear of failure – of what the Japanese

were up to behind the screen of Purple – followed

him home every night. “He’d be up until two or

three in the morning,” Elizebeth recalled later.

“Sometimes I’d awaken and find him down in the

kitchen making a Dagwood sandwich in the middle

of the night.” She remembered that her husband

never discussed his difficulties with Purple, not

even on the day in the fall of 1940 when the deciphering first succeeded. (For years, all he would tell

his son, John, about his job was that he “worked for

the Army.”)

The team spent a total of eighteen months puzzling out the mechanism and the nest of wiring

Page 201
from their calculations on how the original machine

converted plaintext to cipher. Then, out of $684.65

worth of parts, they went ahead and built their own

reconstruction of the Purple machine.

The Purple disclosures (codenamed “Magic”)

proved extremely valuable during the war.

Ironically, says David Kahn, Magic “had its greatest

effect on the war against Germany, not Japan,

became we were getting a great deal of information

that the Japanese ambassador in Berlin was sending back to Tokyo.” For example, the ambassador,

Baron Oshima, described Germany’s new jet fighters in detail, and he listed German troop strength in

the Balkans. Oshima even cabled a close description of the Normandy defenses in late 1943.

Unfortunately, Magic did not clearly reveal the

Japanese intention to attack Pearl Harbor – signals

only indicated an impending crisis between

America and Japan.

Codebreaking definitely changed the course of

the war. The Allies made three major breakthroughs in all: the Japanese diplomatic cipher,

Purple; the main German military cipher called

“Enigma,” which was broken by the Polish and

British; and the Japanese fleet code, broken by the

U.S. Navy, which made possible many American

victories including the Battle of Midway. What

made the breaking of Purple so extraordinary, says

author Louis Kruh, is that the SIS had no pieces of

the machine to study. When the team studied genuine Purple components after the war; he adds,

they found that, out of all the thousands of soldered

connections, “only two wiring connections turned

out to have been interchanged.”

Due largely to overwork on Purple, William suffered a mental breakdown at the turn of the year,

and spent the next three months recovering in

Walter Reed Hospital. Though the hospital recommended he return to duty, shortly afterward the

Army discharged him from service. He served out

the war as a civilian, organizing attacks on new

cipher systems and rapidly training more cipher

personnel.

“The war years were horrendous,” recalls his

daughter. “He was very, very involved in his work. I

remember being worried to death about Dad.”

Attacks of depression severe enough to require psychiatric treatment or hospitalization would return

again.

Wartime associates remember William as

demanding and brilliant. “When working on a

problem,” recalls Frank Rowlett, “he was inclined

to develop a plan of attack which he usually followed meticulously until the problem was either

solved or it could be established that the attack

would not be successful. His memory was excellent

and he had a most unusual ability to grasp the complexity of a problem.” Lambros Callimahos, a concert flutist who became a codebreaker in 1942,

remembered Friedman as the “dapper figure with

the Adolphe Menjou mustache, the characteristic

bow tie, and the two-tone black-and-white shoes.”

Friedman was notoriously meticulous, even to the

point of keeping carbon copies of handwritten

notes. Judy Friedman, his daughter-in-law,

remembers her first weekend visit with the family.

John had forewarned her that if his father failed to

criticize her language, that meant she hadn’t made

the grade. Throughout the weekend, there was not

a single comment from William about her speech.

Judy was crushed. Then, upon leaving the house, he

leaned close and whispered, “My dear, you made

five grammatical errors this weekend,” and proceeded to elaborate on them. Nothing could have

pleased her more.

After the war, the Army restored William’s rank

and he served as a top-ranking cryptanalyst in the

various agencies leading up to the present National

Security Agency (NSA). In 1956 Congress awarded

him $100,000, partly in compensation for many of

his inventions that were so sensitive and useful that

the military had kept them off the market. One of

these, a mechanism he had developed with Frank

Rowlett, was the basis of the SIGABA machine,

which the U.S. military used as its top-level enciphering device during World War II. The Axis never

penetrated its messages.

Page 202
William retired officially from the NSA in 1955

but continued to undertake various special and

highly secret missions. His relations with the NSA

were stormy at times; he believed the Agency sometimes mistreated him and that it snooped excessively into citizens’ communications. The NSA, in

turn, occasionally saw him as a security risk; in

1958 three NSA employees appeared at his Capitol

Hill house and carried off a stack of papers.

Elizebeth finished her professional career as a

consultant for the International Monetary Fund,

setting up a secure communications system there.

Toward the end of their careers (William died in

1969 and Elizebeth in 1980), the couple returned to

the unlikely project that had first seduced them into

the world of cryptography – the Shakespeare problem. Their incisive book, titled The Shakespearean

Ciphers Examined, won them a Folger Shakespeare

Library award in 1955. And in a classic demonstration of their life’s work, Elizebeth and William

Friedman included a hidden biliteral cipher on

page 257 of the book. Buried in an italicized phrase,

using two different typefaces, is their final verdict

about the whole controversy: “I did not write the

plays. F. Bacon.”

Page 203

Solution to cipher on page 197:

This is a sample of ordinary English. But don’t

assume that all English must follow the letter-frequency counts. For instance, an author named

Ernest Vincent Wright wrote a full-length novel

titled Gadsby without using the letter E a single

time. This incredible feat has not been duplicated.

To appreciate Wright’s achievement, try writing a

note to a friend without using the letter E.
Page 204
Editor’s Note: Reprinted from the Special Issue of

Cryptologic Spectrum, December 1980.

Elizebeth Smith Friedman, the widow of

William F. Friedman and herself a pioneer in U.S.

cryptology, died on 31 October 1980 in Plainfield,

New Jersey, at the age of 88. Coauthor (with her

husband) of The Shakespearean Ciphers

Examined and author of many technical papers,

she was employed at various times by the U.S.

Treasury Department, the U.S. Army, the U.S.

Navy, the Canadian government, and the

International Monetary Fund. Mrs. Friedman

served the U.S. as a cryptologist in both World

Wars, and in the period between she won distinction for her work on international drug and liquor

smuggling cases.

The youngest of nine children of John M.

Smith, a Quaker dairyman and banker, and his wife

Sopha Strock Smith, Mrs. Friedman was born in

Huntington, Indiana, in 1892.1 She attended

Wooster College briefly and graduated from

Hillsdale College in Michigan, where she majored

in English.

While working at the Newberry Library in

Chicago in 1916, Mrs. Friedman was recruited by

George Fabyan to work on his 500-acre estate –

Riverbank – at Geneva, Illinois, to aid Mrs.

Elizabeth Wells Gallup in her attempt to prove that

Sir Francis Bacon wrote Shakespeare’s plays and

sonnets. Fabyan, a wealthy textile merchant who

maintained laboratories in acoustics, chemistry,

and genetics, had established a Department of

Ciphers, which consisted of a staff of fifteen who

lived on the estate.

It was at Riverbank that Elizebeth Smith met

William F. Friedman, head of Fabyan’s Department

of Genetics at the time. They were married in May

1917 and worked together at Geneva, the only cryptologic laboratory in the country, solving messages

that government agencies sent from Washington.

During World War I, they developed courses in

cryptology and trained U.S. Army officers and civilians.

After William Friedman’s service with the

American Expeditionary Force in Europe, the

Friedmans returned to Riverbank, but in 1921 they

moved to Washington where they both were

employed by the War Department.

It was Elizebeth Friedman’s own work for various branches of the government that brought her to

prominence, first as assistant cryptanalyst for the

War Department in 1921-22 and then as cryptanalyst for the U.S. Navy in 1923, which led to her work

for the U.S. Treasury Bureau of Prohibition and

Bureau of Customs. Most of her professional career

was spent working against such international

enterprises as smuggling and drug running. She

broke up criminal syndicates and interrupted millions of dollars worth of illegal business. Although

her work itself was not dangerous, on several occasions when she was called to testify, the government supplied her with bodyguards.

Her early career began during the era of

Prohibition, when rumrunners turned to radio and

encoded messages to control their offshore operations. Mrs. Friedman was established in the Coast

Guard office in Washington, D.C., to work on rumrunners’ traffic. In her first three years she solved

12,000 messages as special agent of the Bureau of

Foreign Control, originally in the Department of

Justice. In 1928 she was transferred to the Customs

Investigative Service in the Bureau of Customs,

Page 205

Elizebeth Smith Friedman

1892-1980
Treasury Department, which eventually became the

Bureau of Narcotics.

During 1928-30 her cases centered on smuggling operations in the Gulf of Mexico and on the

Pacific Coast. She appeared as an expert witness in

several cases in Galveston and Houston, Texas, and

in New Orleans, Louisiana. In 1933 she was the star

prosecution witness in the New Orleans Federal

Court as cryptanalyst for the Coast Guard, testifying

to her solutions of messages from the Consolidated

Exporters Company, Prohibition’s largest and most

powerful bootlegging ring – messages that connected ringleaders to the actual operations of the rumrunning vessels. Her evidence at the trial indicted

thirty-five rumrunners for conspiracy to violate the

National Prohibition Act.

Her arguments for the establishment of a

seven-man cryptanalytic section at headquarters

was approved by Congress in 1931, and in the following years she solved not only bootlegging messages but also those of other highly organized

smuggling gangs.

Another outstanding case involved messages of

opium dealers. In 1937 the Canadian government

sought her help. She went to Vancouver to testify in

the trial of Gordon Lim and several other Chinese.

Their secret messages dealing with opium smuggling were cast in a complicated system involving a

code she solved without knowing Chinese. They

were convicted and sentenced to seven years’

imprisonment, where, as a Pacific Coast columnist

observed, they would have plenty of time “to devise

a code that a woman couldn’t break.”

In 1934 some of her solutions helped to extricate the United States from an embarrassing diplomatic tangle in the I’m Alone case, establishing a

point of international law. The ship, built in Canada

for the liquor trade, was sighted by a Coast Guard

cutter on 23 March 1929, near the Louisiana coast.

When the I’m Alone refused to honor the “heave to

and be searched” signals, the cutter chased it into

international waters and sank it with its Canadian

flag still flying. Members of the crew were rescued,

but for the loss of the vessel and its cargo, the

Canadian government filed a claim against the

United States for $365,000, based on the presumption that vessel and cargo were Canadian owned.

American officials contended that the I’m Alone

belonged to New Yorkers. International sentiments

were aroused, and the U.S. embassy in Paris was

stormed as a result of what was considered

American high-handedness. However, with

Elizebeth Friedman’s decryption of twenty-three

coded messages subpoenaed from telegraph company files addressed from Belize, British Honduras,

to an unregistered code address in New York, the

mystery was solved, the owner of the ship captured,

and American ownership fully established.

Another case in which Mrs. Friedman’s solutions proved crucial was the Doll Woman Case,

solved in 1944. Mrs. Velvalee Dickinson, an antique

doll dealer in New York City, was eventually found

guilty of spying for the Japanese government.

Suspicion of her activities while a member of the

Japanese-American Society arose from a letter containing coded information hidden in obscure phrases about naval vessel movement in Pearl Harbor.

After her service as a cryptologist with the government in World War II, Mrs. Friedman, working

as a consultant, created communications security

systems for the International Monetary Fund.

The Friedmans’ earlier interest in Shakespeare

led to a lifelong battle against the doctrine supported by invalid decipherments of Shakespeare’s plays,

which others used to attempt to prove that Bacon

was the author. They collaborated on a manuscript

entitled “The Cryptologist Looks at Shakespeare,”

subsequently published as The Shakespearean

Ciphers Examined, which won awards from the

Folger Shakespeare Library (1955) and the

American Shakespeare Theater and Academy. In

this work, the Friedmans dismissed such Baconians

as Mrs. Gallup and Mr. Ignatius Donnelly with a

combination of technical skill and literary grace

that won the book recognition far beyond those

Page 206
interested in the subject. It is generally regarded as

the definitive work on the subject, if not the final

word.

In 1938 Mrs. Friedman received an honorary

LL.D. from Hillsdale College. 

After her husband’s death in 1969, Mrs.

Friedman spent her retirement compiling a bibliography of his work and library for presentation to the

George C. Marshall Research Library in Lexington,

Virginia. It is considered the most extensive private

collection of cryptologic material in the world.

NOTES

1. The spelling of Mrs. Friedman’s first name was

chosen by her mother, who wanted no one to call her

daughter “Eliza.”

Page 207
Page 208
Page 209

ADFGVX Cipher: 109-112

Advancement of Learning, The: 29, 172, 183

AEF Staff Code: 127

Aeneas Taciticus: 20

Alberti, Leon Battista: 140-141

Alexander, General E. P.: 25, 48, 55, 61, 73, 75, 86-87,

191

Alexander, General J. H.: 87

Alfred the Great: 21

American Black Chamber, The: 95, 98-99, 184

American Expeditionary Forces (AEF) cryptosystems,

WW I: 124

American Lake Series (codes): 125

American River Series (codes): 125

American Shakespeare Theater and Academy Award:

206

American Telephone and Telegraph (AT&T) Company:

162, 165-166, 190

Andre, Major John: 38

Archbishop of Naples: 22

Arlington Hall Station: 185

Armed Forces Security Agency: 192

Army Cipher Bureau (See Cipher Bureau)

Army Security Agency: 170, 185, 192

Army Signal Corps: 56, 134, 191

Arnold, Benedict: 38-39

Arnold, General Hap: 170

Atchison, Barbara Friedman: 200

AT&T (See American Telephone and Telegraph

Company)

Bacon, Sir Francis: 14, 29-33, 139, 160, 183, 196-197,

203, 205-206

Bakeless, Colonel John: 35-39, 183

Barker, Captain William N.: 76

Bates, David Homer: 67-68, 84-86, 183

Battle of Tannenberg: 25, 123-124

Baudot Code: 160

Bazeries, Commandant: 105, 146, 148, 183

Beckwith: 59, 86

Bell Telephone Laboratories: 17

Benjamin, Judah P.: 35, 42, 58, 77

Biblical ciphers: 20

Bi-literaire Alphabet: 31

Biliteral cipher (Bacon): 32, 197

Blackstone, Sir William: 35

Booth, John Wilkes: 77

Bradley, General Omar: 133, 170, 183

Breasted, James Henry: 17

Bridges, Philip: 78-79

British Black Chamber: 112, 115

Brown, J. Willard: 66, 80-84, 87, 183-184

Budge, Dr. E.A. Wallis: 46, 48, 183

Buell, Major General D.C.: 79-80, 130

Bureau of Customs: 205

Bureau of Foreign Control: 205

Bureau of Narcotics: 206

Bureau of Prohibition: 205

Burnside, Major General Ambrose E.: 84-85

Byrd, William: 13

Caesar, Julius: 21, 197

Caesar, Augustus: 30-31

Callimahos, Lambros: 194, 202

Cameron, Simon: 57, 64, 67

Carnet Reduit: 118

Cartouches: 46-48

Casablanca Conference: 137

Chamberlin, General: 6

Champollion, Jean Francois: 43, 46, 51, 183

Charlemagne: 21

Charles the First: 21, 29

Church, Dr. Benjamin: 35

Churchill, Brigadier General Marlborough: 164

Churchill, Winston: 170, 176

Cicero: 21

Cifax: 11, 166-167

Cifrario Militare Tascabile: 121

Cipher Bureau: 27, 110, 197-198, 200

Cipher Device, Type M-94: 148

Cipher-Machine Company of Berlin: 153

Index
Page 210

Ciphers: 7-9, 19, 22-24, 26, 28, 30, 33, 35-36, 52, 55-56,

61, 63-64, 67-69, 73-76, 80, 84, 87, 91-92, 94-96, 98-

100, 105, 108, 108-110, 112, 118, 121, 123, 130, 135, 140,

145, 167, 170, 183-184, 192-193, 195-200, 203, 205-206

Ciphony: 11, 166-167

Civision: 11

Clarke, Colonel Carter W.: 135, 174, 178-181

Cleopatra: 46-48

Clinton, Sir Henry: 35-42

Clock Cipher: 21

Coast Guard: 148-149, 195, 200, 205-206

Code and Cipher Solving Section: 109, 190

Code and Cipher Systems, Revolutionary War: 35-36

Code and Signal Section (Navy): 167

Code Compilation Service: 125

Codes: 4, 6-9, 9, 25, 27, 35, 52, 55-56, 61, 70-71, 76, 82,

84, 97-100, 109-110, 113-118, 121, 124-125, 127, 130,

134-135, 138, 165, 170, 178-179, 183-184, 188, 195-198,

200-201

COMINT: 6, 10-11, 134-136, 139, 169, 180

Communications and Records Division (Department of

State): 9, 91, 95, 149, 165

COMSEC: 10-11, 133-134, 137, 169-170

Confederate cipher systems: 74-75

Confederate Signal Corps: 55, 58, 61, 63, 75, 86, 140

Confederate States Cipher Key: 73

Converter M-134: 158-159

Converter M-209: 160

Coral Sea, Battle of: 5, 173, 178, 180, 184

Corderman, W. Preston: 192

Court Ciphers: 24

Cryppy, Dr.: 3, 43

Cryptanalysis: 6, 10, 13, 15, 17, 23, 44, 48, 87, 81, 101,

106, 112, 115, 124-125, 133, 137, 166-167, 169, 170, 185-

187, 189, 191-192, 194, 198-199

Cryptogram: 3, 7-10, 13, 15, 72, 78-79, 85, 105, 112, 189

Cryptographe B-21: 151

Cryptographe Cylindrique: 146

Cryptographer: 7

Cryptographic Clerk: 7-8

Cryptographic devices, history and development: 25,

133, 140

Cryptography: 3, 6-8, 13, 15, 17, 19-25, 27, 37, 42, 48,

50-52, 60, 64, 77, 86-87, 91-92, 99, 102, 108-109, 115,

123, 125, 133, 140, 169, 183-184, 189, 192, 198-199, 203

“Cryptologist Looks at Shakespeare, The”: 206

Cryptology: 1-7, 9-11, 14-15, 17, 22-23, 27, 29, 33, 36,

43, 51-52, 56, 60, 64, 91, 95, 100, 105, 107, 115-117, 121-

122, 124-125, 133, 137, 139-140, 170, 185, 192-195, 198,

201, 205

CSP-1515: 166

Davis, President Jefferson: 75, 80 

De Augmentis Scientiarum (Bacon): 31, 183

Deciphering: 4, 7-8, 13, 20, 24, 51, 67, 70, 80, 83, 93,

105, 118, 122-124, 127, 153, 164, 178, 195, 201

Decrypt: 7, 17

Demotic Script: 44

Deuxieme Bureau: 112

Dewey, Admiral George: 4, 102, 135, 171, 173-175, 177,

179-180

Dewey, Governor Thomas E.: 173-174, 177

Dickinson, Velvalee: 206

Division Field Codes: 165

Doll Woman Case: 206

Donnelly, Ignatius: 206

Donovan, William: 179, 200

Drioton, Prof. Étienne: 50, 52, 54, 183

ECM (Electric Cipher Machine) Mark II: 158

ECM-SIGABA: 158-159, 166, 202

Egyptian Hieroglyphics: 43, 46, 48, 50-51, 183

Elements of Cryptanalysis: 187, 189, 192

ELINT: 10-11

Encoder: 8

Encoding: 8, 24, 42, 115, 178

Enciphering: 7-8, 14, 24, 63, 76, 86, 97, 102, 116, 118,

122, 125, 141, 153, 161, 163, 187, 202

Encrypt: 7-8

ENIGMA: 153-156, 202

Fabyan, Colonel George: 107-109, 140, 163-164, 190,

195-199, 205

Falconer, James: 64, 183

Federal Signal Corps: 61, 78, 87

Feis, Dr. Herbert: 136

Field Codes No.1, 2, 3: 109, 116-118, 125, 130, 165, 183

“Field Codes used by the German Army During the

World War”: 109, 118

Fishel, Edwin C.: 76, 78

Folger Shakespeare Library Award: 203

Franklin, Benjamin (cipher system): 35, 42

French Army Cipher Bureau: 110, 118-119, 146

French Black Chamber (See Deuxieme Bureau)
Page 211

French cryptosystems, WWI: 24-25, 28, 42-43, 95-96,

105, 110, 112, 115, 118-119, 124, 130, 144, 146, 195

Freeman, Douglas S.: 83

Friedman, Barbara (See Atchison, Barbara Friedman)

Friedman, John: 201

Friedman, Judy: 202

Front Line Code: 125

Galileo: 13

Gallup, Elizabeth Wells: 196-197, 205-206

Garamond: 32

GEHEIMKLAPPE: 116

George C. Marshall Research Library: 207

George III: 29

German Code and Cipher Solving Section: 109

German diplomatic codes, WWI: 113-115, 184

German military cryptocommunications, WW I: 115

Gerow, Lieutenant General Leonard T.: 175, 179

Givierge, General: 112

Grant, General Ulysses S.: 59, 72-74

Greely, General A.W.: 99

Greene, Major General Nathaniel: 41

Gregory, Colonel J. F.: 97-98, 183

Gripsholm Castle: 21

Grosvenor, Colonel William M.: 92

Gylden, Yves: 115

Hagelin, Boris: 159-160

Halleck, Major General H. W.: 79-80, 82, 130

Halsey, Fleet Admiral William F.: 138

Hassard, John R.G.: 92-94, 183

Haswell, John H.: 93, 182

Hatted Code: 71, 115, 117, 125

Hayes-Tilden election: 91-92

Hebern, Edward H.: 199

Hebern Cipher Machine: 201

Hitt, Captain Parker: 108-109, 146-148, 165, 184

Holden, Professor Edward S.: 92-94, 98, 112, 184

House, Colonel Edward M.: 9

Howe, General William: 35

Hull, Cordell: 136, 184

Huntington, S.H.: 141, 205

Hurt, John: 201

Huygens: 13

I’m Alone Case: 200, 206

Imprint: 33

Index of Coincidence and Its Applications in

Cryptography, The: 189, 198

International Business Machines (IBM): 167-168

International Monetary Fund: 203, 205-206

International Telephone and Telegraph (IT&T)

Company: 165

Jefferson Papers: 105, 148

Jefferson’s Wheel Cypher: 105

Jefferson, Thomas: 42, 105

Johnston, J.E., General: 80

Joint Congressional Committee on the Investigation

of the Pearl Harbor Attack: 5, 133, 173, 175, 192

Kahn, David: 198, 202

Kaiski, Major: 103, 105

Key: 7, 9-10, 28-29, 31, 35, 39, 41-42, 63-64, 73, 75-76,

84-85, 87, 92-96, 107, 111-112, 114, 116, 122, 124, 146,

149, 151, 153-155, 160-166, 170, 180, 185, 190, 192, 196,

198, 200

Kimmel, Admiral Husband E.: 136, 184

King, Admiral Ernest J.: 174, 177, 180

King’s General Cipher: 24

Knepper, Captain Edward W.: USN: 41

Kruh, Louis: 199, 202

Kryha Machine: 149

Kullback, Solomon: 186, 191, 201

Lake Series (See American Lake Series)

Lavinde, Gabriele: 22

Lim, Gordon: 206

Lincoln, President Abraham: 75, 84

Louis XIII: 24

Louis XIV: 25

Louis XV: 25

Louis XVI: 25

Lovell, James: 41

M-94 (See Cipher Device Type M-94)

M-134 (See Converter M-134)

M-138A (See Strip Cipher Device Type, M-138A)

MacArthur, General Douglas: 6

MAGIC: 5-6, 10, 57, 136, 168-169, 173-175, 203

Majority Report (See Joint Congressional Committee

on the Investigation of the Pearl Harbor Attack)

Maltese Inquisitor: 26

Manly, Captain John M.: 148

Mark II (See ECM Mark II)

Marshall-Dewey Letters: 177

Marshall, General George C.: 4, 177, 207

Mary, Queen of Scots: 27

Masonic Cipher: 38
Page 212

Mauborgne, Major General J. O.: 109, 146-148, 164,

184

McClellan, General: 64

Mendelsohn, Captain Charles J.: 113

Michigan Papyrus: 51

Midway, Battle of: 103, 136, 169-171, 202

Miles, Major General Sherman: 136, 175

Military Cryptanalysis, Parts I-IV: 187, 191

Military Cryptographic Service (Russian WWI): 25, 121-

124, 196

Military Telegraph Corps (See USMTC)

Minority Report (See Joint Congressional Committee

on the Investigation of the Pearl Harbor Attack)

Monoalphabetic substitution: 23, 35-36, 86

Morehouse, L.F.: 172

Moorman, Colonel Frank: 117

Morison, Admiral Samuel Eliot: 136, 184

Myer, Brigadier General Albert J.: 55-56, 60

Naples, Archbishop of: 22

Napoleon: 25, 43

Napoleonic Code: 7

Naval Security Group: 103

NCB (Navy Cipher Box): 103

Nicodemus, Lieutenant Colonel: 59

O’Brien, J.E.: 63-64, 184

Ogam Writing: 21

One-part code: 24

Oshima, Ambassador Baron: 5, 173 ,178, 202

Page, Ambassador: 9, 106

Painvin, Captain Georges: 110

Papal states’ ciphers: 22, 24, 65

Parker, R.D.: 162-164, 172

Pearl Harbor Committee (See Joint Congressional

Committee on the Investigation of the Pearl Harbor

Attack)

Pemberton, Lieutenant General J.C.: 73-74

Pepys, Samuel: 13

Philae Obelisk: 46-47

Philip II: 28

Pigpen Cipher: 37-38

Playfair Cipher: 109, 119, 124

Pletts Cryptographs: 195

Plum, Colonel William R.: 64

Pocket Military Cipher: 121

Poe, Edgar Allan: 13, 23, 26, 52, 175

Polyalphabetic Cipher: 63

Polyalphabetic Wheel: 191

Porta: 28-29, 140

Porta’s Alphabets: 28

Porta Table: 28

Ptolemaic Period: 44

PURPLE: 180, 192, 201-202

Radio Intelligence Section: 109

Radio Service Code: 130

Rebus: 17-18

Red Cipher Machine: 3, 38, 54, 174, 201

Revolutionary Congress: 43

Rhoads, Lieutenant Mark: 186, 192

Richelieu, Cardinal de: 24, 27

River Series (See American River Series)

Riverbank Laboratories: 107, 109, 145-147, 163-165,

167, 184, 190-191, 195-199, 205

Room 40 O.B.: 105-106, 112

Roosevelt, President Franklin D.: 174, 176

Roosevelt, President Theodore: 102

Rosetta Stone: 43-44, 46, 48, 183-184

Rossignol, Antonio: 24-25

Ross, Professor Alan C.: 51

Rowlett, Frank. B.: 2, 165, 186, 191, 201-202

Satzbuch Code: 116, 125

Savinsky: 121

SCHLUESSELHEFT Code: 116

SCL (See Signal Corps Laboratories)

Scriven, Brigadier General George P.: 100

Scytale: 20-21 

Second Army Trench Code: 125, 127

Secret Inks: 11, 36

Secret Signaling System: 162

Secret Writing: 11, 20, 50, 60, 95, 184

Shakespearean Ciphers Examined, The: 33, 183, 193,

203, 205-206

Shakespeare, William: 33, 193, 196-197, 203, 205-206

Short, Lieutenant General Walter C.: 175

SIGABA (See ECM-SIGABA)

SIGCUM: 166

SIGINT: 10

Signal Corps (See Army Signal Corps)

Signal Corps Cipher Disk: 124

Signal Corps Laboratories (SCL), Ft. Monmouth: 158-

159

Signal Intelligence School: 192

Signal Intelligence Section: 191
Page 213

Signal Intelligence Service (SIS): 111-112, 139, 159-160,

163-166, 168, 171, 200-202

SIGSALY: 166

Simonetta, Sicco: 23

Sinkov, Abraham: 186, 191, 201

Slater, Robert: 96

Slater’s Code: 96-100, 184

Smith-Corona Typewriter Company: 160

SPARTAN Dispatch: 32

Stager, Colonel Anson: 57, 64, 67-68, 79

Spottswood, W.G.: 97-98

Stanton, Edwin M.: 57-59, 61, 69, 73

Stark, Admiral Harold R.: 175

Stern, Philip Van Doren: 77

Stimson, Henry L.: 136, 184, 200

Strategic Ciphers: 63

Strip Cipher Device Type M-138A: 149

Substitution Cipher: 8, 35-37, 51, 99, 110, 112

Sullivan, General John: 38

Syllabary/repertory: 22, 24, 35, 43

Taciticus, Aeneas: 20

Tactical Ciphers: 63

Tannenberg, Battle of: 25, 123-124

Taylor, Dr. Charles E.: 75

Taylor, Daniel: 39

Teletype Corporation: 158, 166

Thomas, General G.H.: 62

Thompson, Dr. George R.: 57, 61

Tilden, Samuel J.: 91-92, 95, 183-184

Tiltman, Brigadier John H.: 186

Tiro: 21

Transposition Cipher: 8, 35, 63-64, 66-67, 69-72, 79,

93-94, 109-110, 112, 118, 189-190

Trench Code: 125

Trithemius: 27

TSEC/KL-7 Cipher Machine: 10

Two-letter differential: 70

Two-part codes: 71

TYPEX: 158

Union cipher systems: 56-58

Union Signal Corps: 61

USMTC (United States Military Telegraph Corps): 58-

59, 61, 63-64, 67-69, 72-73, 75-76, 78-79, 84, 86, 94-95,

118, 130

U.S. Navy Secret Code, 1880s: 96

Vatican: 22-23, 27

Vatican Codex: 23

Vernam, Gilbert S.: 161-162

Viaris, Marquis de: 105, 146, 184

Vieta: 28

Vigenère Cipher: 35, 73, 86-87

Vigenère Square: 29, 73, 140

Vigenère Table (Tableau): 29

Vint Hill Farms: 185

Wadsworth, Colonel Decius: 145-146

Wallis, John: 25, 46, 105, 183

War Department Cipher: 63, 65

War Department Telegraphic Code: 99-100

Wats, Gilbert: 29, 31, 183

Wedemeyer, General Albert C.: 135, 184

Western Union Telegraphic Code: 99-100

Weston, Reverend Stephen: 44

Wheatstone, Sir Charles: 141, 144-146, 184, 190

Wheel Cypher, The: 105, 148

Whitney, Eli: 145-146

Wiener, Professor Norbert: 44

Wig-wag (two element) Code: 56, 58, 60-62, 83

Wilhelm Cipher: 112

Wilson, President Woodrow: 9, 106-107

Wimsatt, Professor W.K.: 52, 184

Wolsey, Cardinal Thomas: 21

Worcester, Marquis of: 21

Writing, History of: 25-47

Yamamoto, Admiral Isoroku: 136-138, 169, 173

Yardley, Herbert O.: 95-96, 99, 147, 164, 184

Young, Dr. Thomas: 44

Zimmermann Telegram: 7, 105-107, 112, 184