• REF ID:A65313 • 

RANDOM NOTES 

~lhile en route to visit the War Office intercept station 

at Beau.manor I undertook to obtain a bit of information from 

Colonel Lycett regarding the organization and functions of 

the War Office bureau in which he was assigned and the following notes are based upon the answer to various questions I 

raised. 

Colonel Lycett drew a rough ch.a.rt showing where he fitted 

in the organization anathis is attached hereto. The duality in responsibility to two different branches of the War Office 

organization is interesting to note in the case of Colonel 

Lycett•s position inasmuch as he is responsible to both DMI 

and the Director of Signals. Another interesting thing to 

note is that although the military wing which comprises No. IV 

and No. VI Intelligence Schools of GC & CS belonged to MI-BA, 

Colonel Tiltman, the commander of the military wing reports directly to Colonel Lycett and not to the Chief of MI;8, 

Colonel Vernham. It is also interesting to note that Briga- dier Nolder is responsible for the production and distribution of code and ciphers but these are printed at Oxford by 

~ 

I 

(4) 

a group which is under GC & CS. 

Signals 4 is responsible for the procurement of Y per- sonnel and equipment for them as well as for training. When 

the unit is completely trained it is turned over to Home 

Forces or to Overseas Commands. 

0 

-l 

0 

On the staff of superior units of Home Forces and Overseas Forces is an officer called GSIS representing General 

Staff Intelligence and Signals. This officer is familar with 

the functions and work of the GC & CS and therefore does not 

allow his unit to undertake Y work inconsistent with higher policy although Y work in these forces is theoretically independent. Signals VI hs.s practical control by virtue of 

its control over the personnel and equipment supplied them. 

Home Forces interception is autonomous but usually there are 

a few sets assigned to high-grade intercept work at Harpenden which is the Home Forces Y Group Headquarters station. 

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Declassified and approved for release by NSA on 04-30-2014 pursuantto E.O. 1352a 
I 

I\) 

I 

DMI 

Director of Military Intelligence (Maj. Gen. Davidson) 

D Bigs 

Director of Signals (Maj. Gen. Fladgate) 

D ~ DD Sigs (0) 

Deputy Director Deputy Director 

Military Y Org. or Signals 

(Colonel Lycett)4-----, (Brig. Nolder) 

..-----------------------~!..._ ______ ~ i Technical I l Liaison 

MI-8 sigs -4 - Security- - + Sigs-6 

(Col. Vernham) Intercept apparatus (Mr. Williams) 

I 

MI-BA* I and personnel pro- Code and Cipher t curement and training Compilation and 

MI-8B MI-8C production policies, 

Intercept 

policies 

and direction of field 

intercept,; 

certain amount 

of intelligence. 

All questions 

re Intelligence 

Corps personnel of Y Service. 

Information 

on Communications in 

enemy occupied and. neutral 

territories. 

*Military Wing of GC & CS (Col. Tiltman) including No. IV and No. VI Intelligence Schools come under 

MI-SA but Col. Tiltman reports directly to Col. 

Lycett and not to Col. Vernham. 

regulations, etc. 
REF ID: A65313 e 

8EBlll1f 

The headquarters of a field force has a Y group force 

composed of two separate parts. First a special traffic 

analysis groufr and second a radio intelligence group. Each 

army has an "A ' type section which consists of a special radio 

section type "A" and a traffic analysis section type "A". 

Ea.ch corps normally has a. "B" type radio intercept and 

a "B" type traffic analysis unit. 

To handle the ·work and output of these uni ts there is 

a.t the headquarters of field forces a GS0-1 who is the GSIS 

of the unit and has a staff with much the same duties a.s MI-8 

or the War Office. The GS0-1 is usually a Lieutenant Colonel. 

At Army there is a. GS0-2 who is a. Major and is the GSIS 

officer. He devotes his entire time to Y work. 

At Corps there is no special Y officer but one of the 

three intelligence officers on the staff maintains liaison with 

the intelligence staff and gets from them any identifications 

available uhich identifications he fuses with intelligence he 

is able to obtain. 

At Division there is no Y officer specially assigned • . A type "A" radio intelligence unit has twelve receivers 

and three direction-finding sets. The traffic analysis group consists of ten officers and twenty-six other ranks. 

The type "B" radio intelligence unit has eight receivers 

and one direction finder. The traffic analysis consists of 

three officers and twenty other ranks. 

As an example of the kind of work done by a type "A" 

unit the messages of the Phoenix cryptonet was cited. This 

was obtained by a. type 11A11 unit of the Montgomery Army and 

was first noted in the Middle East from what was sent to 

GC & CS where it was found that solution could be obtained. 

Whereupon BP supplied them with Typex equipment and sent them 

solved keys so that the unit in the field could decipher intercepted messages locally; this was done with the ~reatest 

secrecy. All the traffic thus handled by the type "A unit 

was, however, sent to BP. Colonel Lycett indicated that on 

account of the danger and the necessity for speedy communications which are difficult to have in the field this experiment will never be repeated and it has been decided as a matter 
REF ID: A65313 e 

- of policy to keep all of this high-grade material under very close control of GC & CS at BP. 

Colonel Lycett mentioned a-"Wireless Telegraphy Board" 

which was set up after the last war and corresponds to our 

Joint Communication Board at Washington in certain respects. The chairman of the board is a Lieutenant Colonel or an 

officer equivalent in rank in the other services. The members 

of the board are the directors of signals in the three services. 

The chairman is in turn an Army, Navy, or Air Force officer 

who gets a four-year detail in the job. The auties of the 

board are mainly to coordinate all matters affecting communications of the three services. The name of the board is misleading since it deals with all types of communications, radio, 

cable, telephone, etc. The name has stuck because it started 

off as a frequency allocation boarq for the three services. 

In peace the Postmaster General has control over this matter 

of allocation but in wartime this board takes charge. 

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8EORIEY 
• REF ID: A65313 e 

SIGNALS--6 AT THE WAR OFFICE 

(Visited on June 10) 

A small central organization called Signa.ls-6 (with 

three subsections) is maintained at the War Office for work 

in connection with (a) the compilation and distribution of 

War Office and British Army codes and ciphers, (b) the develo~ment, construction, and distribution of cipher devices, 

and (c) the security of military cryptographic communications. 

The group is headed by Mr. J. H. Williams, a Civil Servant 

who has been in charge of these activities for many years. 

He has a staff of four officers and about four or five clerks. 

As regards code and cipher compilation duties, the work 

done here is largely executive or administrative in character. 

Plans for new editions of codes are made, distribution tables 

and data compiled, records of holders maintained, etc. No 

actual compilation or printing work is done here, as these 

functions are performed at Oxford by the inter-service code 

and cipher compilation and reproduction agency under Commander 

R. E. Hok. 

With regard to security studies in connection with their 

own traffic, the only thing done is to keep detailed records 

of traffic volumes in the various systems. All outlying headquarters notify the War Office, by telegraph or radio, of the 

total monthly traffic counts (number of groups) or outgoing cryptographic communications, except as regards messages to the 

War Office. The in and out traffic of the War Office is 

counted in this section from records ma.de available to it by the two sign.al centers maintained at the War Office (see below). Attached to each large overseas command is a Force Security Officer who maintains the same general type of record as regards the communications within the force itself and from the 

force headquarters to other Commands, except London. Monthly 

summaries of intra and inter-unit traffic counts are sent by the various Force Security Officers to the War Office where 

they are combined into one large report. Thus these records 

afford the basis for security control to insure that no system is loaded beyond the safety point. 

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REF ID: A65313 e 

It is to be noted that the job of Force Security Officer, 

who has one assistant as a rule, is a specific assignment on 

the Signals Staff of each command. The policy of having these 

officers has been established for only about one year but 

Mr. Williams assured me that the results were most beneficial 

and that they turned up "an amazing number of things". 

The record keeping for the security studies referred to 

under Par. 3a is done by three women. They draw up, as 

regards systems using general subtractor tables, "depth chal'ts", 

or what we would call ovel'lap charts, showing the supel'imposi- tion of messages in the same segments of the subtractol' tables. 

They also look for stereotypy, study the beginnings and endings of messages, and note the special ha.bits of the code clel'ks who 

encode and encipher the messages; in fact, they actually keep l'ecords showing the idiosyncl'asies of individual clerks so as 

to have a guide fol' admonishing them when necessal'y. Every cryptographic message in and out of the War Office is l'egistered and st~died from these points of view. Just how only three 

women could do this entire job is not clear but I saw the 

depth charts, the books with the various notations as to habits 

of code clerks, etc., so that I am sure there was no great 

amount of exaggeration. 

With regard to studies on Typex traffic, somewhat similar 

data, especially as regards volume, are kept. Incidentally, here is a list of the ten different sets of rotors maintained 

for Typex communications: 

(1) 

(2) 

(3) 

(4) 

(5) 

For special communication only between the War 

Office and the topmost commanders (only the 

C in C1 s) of overseas Commands. 

For general communication between the War Office 

and the commanders of all overseas forces and 

for intercomm:w:;i.ication among those commanders. 

For intercommunication among field units from nHQ 

to Corps, inclusive. 

For special interservice communication, with a 

narrow or limited distribution (high comm.ands). 

For general interservice communication, with a 

wide distribution. 

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e REF ID: A65313 e 

.... I,.-- ~ i>\!.a._i:.. 

For intercommunication among field units from Corps to Div!-

sions or smaller units equipped with Typex ma.chines there 

are five regional sets of rotors, as follows: 

(6) A set for units of the Home Forces (U.K.). 

(7) A set for units of the European Theater. 

(8) A set for units of the North African Theater. 

(9) A set for units of the India Theater. 

(10) A set for units of the Southwest Pacific Theater. 

Sets of subtracter tables are also allotted, according 

to the foregoing specific and general types of distribution, 

for use between the War Office and tactical commands, for 

use within theaters, and for interservice use. 

Mr •. Williams and I had a brief discussion regarding the new device called "Slidex", an advance sample of which 

I had seen in C Branch some time before my trip. He demonstrated a more recent model. (The Slidex is to replace the 

device called the 11Kodex", which has proved to be insecure.) 

This device is to be employed for radiophone communications 

in the combat area and will be provided with separate sets 

of cards for the various services such as A~tillery, Quartermaster, Medical, etc. Besides the foregoing there will be a 

general "operations-signals" card; in addition a "unit card", 

which will be blank and can be filled in with meanings by the individual unit commanders, will be provided. As regards the "cursors" for the Slidex device, they plan to have one 

set of cursor keys for army to division, inclusive, and another 

set for division to battalion, inclusive. The Slidex is-a 

very compact device and is made to fit into the trouser's pocket of the battle-dress uniform. Its cryptographic security is 

fair. I was advised that several copies of the latest device 

will be sent to Arlington Hall in about one month. 

Mr. Williams showed me a copy of each of their two 

principal types of code books. There is a large code (ll.O.) 

for communications between the War Office and the headquarters of overseas Commands. This is a 100,000 group, two-part code 

using five-digit equivalents and the groups are enciphered by means of the usual one-time pads or large general subtracter 

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REF ID: A65313 e 

tables. There is a smaller (10,000 groups) four figure, twopart code for communications from GHQ down to and including division (Inter-Service Cypher). This is to be used nith 

subtra.ctor tables and, within a. short time, with the new 

"stencil subt?'a.ctor frame". These codes so fa.I" a.a the 

largeI" Commands a.I"e conceI"ned S.I"e employed as standby systems for the Typex machine; smalleI" Commands a.broad which do not 

as yet have the Typex, however, I"ely entiI"ely on the code 

with either the subtra.ctor tables or the SS frame. For communication within Brigade there is a sms.11 two-part code called 

the "Brigade Cypher" which is enciphered by .eubtractors and a 

new, small SS frame ha.a been developed for this purpose. 

No cryptanalytic security studies whatsoever are undeI'-

taken by Mr. Williams' organization, but when a problem I'equ1ring cryptanalytic techniques does arise it is referred to 

Colonel Tiltman in his capacity as "Chief Cryptographer to the 

Wa.r Office". As a specific example, he was given the task 

of asceI"taining the security value of the 11Stencil SubtI"actor 

Frame" for general connnunication purposes (not fol" synoptic weather reports) and when I was a. BP the reseaI"ch group under 

Major Morgan was just completing a. rather detailed study of 

the security afforded by the device, based upon a large number 

of test messages which had been prepared for the purpose. Til tma.n retained the "ans'tvers" and Morgan 1 s group tried to 

solve the messages by cI"yptanalysis. The group had ma.de 

little progress and I"epo?'ted that the cryptographic security 

is very high. 

In connection with the Typex machine and the new plug- board arrangement therefor, I learned that all of these 

machines of the Mark II type (the present large ma.chine) 

distributed down to and including Army, are to be provided with a plugboard which is on the reflector or reversing 

rotor (13 connector wires ending in plugs to be inserted in 

jacks). 

It was in Mr. Willia.ms' section that I first learned 

a.bout the new Mark VI Typex machine for field use, developed, 

as was the large Typex, by the RAF. It was described to me 

and was stated to have an opell&ting speed or 90 characters 

per minute. When I expressed a desire to see a model, arrangements were at once made with Wing Commander Johnston or the 

Air MinistI"y to see one. A report will be found under the 

next section. 

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REF ID: A65313 e 

Also under Mr. Williams {~~r "Central Cipher Office" 

which is like our War Department code center, but does work 

only for the following four catagories: 

(1) Payma.sters.~There are about 20 of these scattered 

thl'oughout the United Kingdom at the Headquarters of the regimental areas from which the various regiments are recruited. 

(2) Record Offices.~About 20 scattered as above. These 

are equivalent to local regimental Adjutant General's 

Offices. 

(3) The Soldiers and Sailors Family Associations.~These 

are likewise offices scattered throughout the 

United Kingdom and deal with the welfare of the 

troupe abroad. 

(4) Army Agents.~For officers' pay; likewise scattered 

throughout the regimental areas in the United Kingdom. 

The central cipher office handles between 34,000 and 38,000 

code groups per day. It is "manned" entirely by ATS, a total 

of 38 being employed there as code and cipher clerks. All of 

them are skilled in the use of the Typex ma.chine and in the 

handling of code books with subtractor tables. The central 

cipher office is administered by five ATS officers, the leading 

one a Captain. 

There are eight Typex machines in this office; ten ATS 

comprise a working shift. Supervising the shift is one 

duty officer in charge and one assistant duty officer who 

receives and registers all outgoing and incoming messages for 

cryptographing, indicates the system to be employed and passes the messages on to the code room for actual handling. The 

Typex machines are serviced and maintained by about six 

members of an organization called the HEME, standing for the 

Royal Electrical and Mechanical Engineers. This is a new 

corps composed of maintenance personnel taken from all services. The purpose of establishing this separate corps was 

to eliminate the large amount of duplication which had been 

found in this field. It apparently is working very well. 

The training of the ATS code and cipher operators is 

done at "No. III Intelligence School", which is located at a 

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• REF ID: A65313 e 

secret address in London. ~ Two courses are given there. The 

first is a course in medium-grade work la.sting two weeks, 

where instruction 1s given in the handling of codes with 

subtractor tables and 1n the use of the Typex. The capacity of this course is 20 men and 10 women per week. This course 

is to be extended later to three weeks, when the Mark VI 

Typex comes into use. The second, or high-grade, course is 

given to individuals who have had the medium-grade course 

and have returned, after practical experience has been obtained 

in the work, to do an additional one month's course in more 

advanced code vork. The capacity of this course is 40 men· 

and 30 women per month. 

I was informed th.at there is another much larger code 

center in the War Office designated a.s "C-6-Telegra.ms", but 

did not visit it. The latter handles all the messages directly 

to and from the War Office in connection with intelligence, operations, supplies, administration, etc. The entire section 

handles, on the average, 90,000 code groups per day. This 

organization is the equivalent of our War Department Code 

Center and has a large staff with 30 Typex machines, uhich a.re 

also operated by ATS. I was informed that the supervisory personnel of "C-6-Telegra.ms" are all civil servants, mostly "old-timers". In connection with these supervisory "civil 

servants" I learned a fa.ct of interest and significance so 

far as the British are concerned. When I asked Colonel Lycett why this emphasis was placed upon having civil personnel in 

charge he informed me that under the British system and since 

the time of Cromwell's descent upon Parliment, the principal heads of sections in the War Office are all civil servants. 

In particular, the Permanent Under Secretary of State for War 

is a civil servant who acts as a. watch dog for the government 

to see that the Army does not surreptitiously try to take 

over civil functions and one of his prerogatives and responsi- bilities is to see to it that the civil heads of the government have full knowledge of every important cipher or code 

telegram passing in and out of the War Office. Thus the 

Permanent Under Secretary of State for War has the right to 

see al.J. telegrams and can exercise this right through his 

chief of the code center, who is an old civil servant. 

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REF ID: A65313 e 

THE MARK VI TYPEX 

(Seen on June 11) 

On the morning of this date I was afforded the courtesy of examining the new Mark VI Typex machine for field use, 

the model being at the office of Wing Commander Johnston of 

the Air Ministry. 

The ma.chine is contained in a wooden case approximately 

two feet long by ten inches deep and ten inches high, the top of which is hinged and can be folded back. On the inside o~ 

the top cover are brief instructions for operat~ng the machine; 

there are also containers for reserve tape reels and a "copy holder". The ma.chine in the case weighs approximately 30 lbs. 

Power is supplied either from an external storage battery of 

the 6-volt type usually employed in automobiles or by a set 

of dry cells delivering approximately the same voltage. This 

power is used solely for the cryptographic circuits. The 

actual printing and tape-advance operations are performed by 

means of a hand crank on the ~ight-hand end of the machine. 

The machine can be arranged to be entirely interchange- able in its product with the standard Mark II Typex having five rotors and a reversing wheel. The rotors are, however, 

of a different type than those employed in the Mark II s~nce 

the internal wirings are in the form of a "biscuit" or "insert" 

which can be readily inserted and removed from the core of 

the rotors. Moreover, these "inserts" are reversible so 

that the rotors no longer correspond to the t~e wherein a 

reverse position of the rotor is not possible las ia the case 

with the present type of rotors in the Mark II Typex). Each 

machine comes equiped with a complement of seven such inserts, 

so that, considering their reversibility, the degree of 

security afforded by this type of rotor is much higher than 

with the tll>e of rotor employed in the Mark II machine. The 

plugboard lfor varying the corm.ections in the reversing rotor) is at the left-hand end of the machine, at the base. 

When I inquired as to whether all the Mark VI machines will 

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REF ID:A65313. 

be equipped with this plugboard I was informed th.at only a 

few would be 1 those which might communicate with Mark II 

machines. It seems that the type of plugs and jacks selected 

for this purpose is not suitable for field usage 1 inasmuch as 

the plugs have a tendency to jar loose. They are not of the 

type we use (IBM type) and I could see th.at they would easily 

come out of place. 

The ma.chine is provided with a standard typewriter key- board which is a duplicate of the Mark II keyboard so that 

it can be used in the lower and upper case positions. The 

printing mechanism is at the right of the keyboard and pro- duces a plain text as well as a cipher tape and the characters 

on the tapes are very large and distinct. Automatic grouping into fives 1 in the case of the cipher tape 1 and into the 

original word lengths 1 in the case of the plain-text tape 1 

is provided. A locking mechanism insures th.at only one character will be printed per depression of the key of the keyboard. 

When I said th.at I had been informed th.at the speed of 

this ma.chine was 90 characters per minute 1 Wing Commander 

Johnston indicated th.at this was too enthusiastic an estimate 

and th.at he rated the capacity of the machine at about 60 

characters a minute. I tried out the machine myself and was 

rather impressed with its ease of operation as well as with 

its general ruggedness. 

The first order of 3900 :ma.chines is now in course of 

production and deliveries are to be begun in November 1943. 

A case with spare parts 1 repair kit 1 and dry cells 1 

accompany the ma.chine and one man can carry both the machine 

and the spare-parts case 1 as a balanced load in both hands. 

This :ma.chine will no doubt be very useful. It may be 

interesting to contrast it with our Converters M-325 and 

M-409. Our M-325 will not produce printed texts but does 

not require a hand-crank operation; on the other hand it is very 

much smaller th.an the British Mark VI Typex. Our M-409 will 

produce printed text and will be of about the same weight as 

the Mark VI but will not require hand-crank operation. All 

three will produce cryptograms of very great security but ou:D 

devices will be more secure th.an the British because of the 

special features incorporated in ours which are lacking in theirs. 

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