REF ID:A62832 

Declassified and approved for release by NSA on 12-17-2013 pursuant to E.O. 1352B 
REF ID:A62832 

INTRODUCTION TO CR?PrOLOGY VI 

• 

eorrf :ldent:l:al: 

-.,. -.. - ' _, 

/ 
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REF ID:A62832 

• 

DTROllJCTIOI TO CR?Pl'OLOGY - Vl 

~ = by __!!l!.-(1IILLIAll ., . FRIBllfA!I 

This lecture, the sixth and last in this series, deals with cryptolos;y in 

the ;period tran the end of World Wlr I to the end of World Wlr II (Unclassified 

material only). The emp!!.sis in this lecture is u;pon ccmmnmications security 

(C~) not only because in the five Feced1Dg lectures the emp!Jasis was p]aced 

very large].y up cammmications intelligence (CCKD'l') but also because although. 

in the final ana more vital 

to National Security than C<MDT. 

the very first lecture 

Mil-

. ,..,.,.,..7 t~ete n ene saall bu e:xbezme}J •'pi;Ha&M :piece cl ~ian-H-

..., 

Wo"'snd 1r 1'91 •**•• alli I will ass a few lf8'!1a aeCNt it:. You will recall that in . ;,_ & ,, i>~ 1946'9~ .. ·ot1'M& 'Iv\~...,> the first lecture I called to your attention an article which appeared,.and wh eh was 

'1-lo:t 

baaed upon a letter" the late General George C. Marshall, then Chief of Staft of the 

Army, wrote to Governor Thomas E. Devey, Republican candidate for President in the 

~w~ ~~~~ ~ ~it.iw4oi...Lal"°KJ'"t-~{r-(.s. 1944 election campaign.A In tba'\. letter which was written on 27 Sept. 1944, General 

Marshall practically begged Governor Devey to say nothing during the campa.ign about 

a certain piece of very vital information which General Marshall.bad reason to believe 
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REF ID:A62832 

giia, the a:fxth and fiDal. lecture in this aeries cm the history of 

~ 

cl'JP'toloSJ_,will be devoted to a presentaticm. of" events and developnents of 

aigDificance or 1D;K>rtaDce in that history fi"m the em. of World War I to the 

end of World War II. 

It would be enti:i:oeq too ambitious a proJect even to attempt to caupreas 

within a lecture of onlJ' 50 minutes all that should or could be told 1D that 

sesmmt of our history of c:r;yptology. In a nutshell., however, it can be said tbat the 

most significant and ~t events and developnents du:r1Dg that quarter of 

a century were directly' ccm.cerned or camiected w1 th the advances made 1D the • 

machines. '1lese two pbasea are inter-related because, to use a Blmbcof sim;ple 

.&vcw ON4. ,..,.__..._ 

BZJ&logy, crnrt;ograpby and cryptaml.ysia represent the ~ faces of a single 

co1DJ2 

vaild be Dice 1f' I could go 1 7 It int::;=l 1D regvd to tbeae 

1Dcreas:l.ngl.J' caa;plex matters but aecur:l:by ccm.sideratians prevent m;y doiDS so. 

gas '!Ii• p;1213 As to 9R advances 1D the devel.opmmt and use of more c..,.· f'til ..,,,. 

soph~sticated crnt;ographic apparatus I w:lll. onlJ' note at this point a caamen.t 

which GeDeraJ. Qmi" Bradley Ekes 1D his quiet but very 1Dtersting book entitled 

A Soldier's stori:~ 

~ Nev York: JleDl7 Bolt and Co., 1951, page 474. 

la. 
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Signal. Corps officers like to rem:lnd us that "althougb Cc:mgress 

can mk:e a general, it takes ccmmmicatima to m.ke h1m a carnrmmder." 

It is ~t:'- ta bq: to amend General Bradl.ey' a remark but this 

is how I wish he had worded it: 

Sigaa.t Corps officers lildl to remind us that "al.thou&b Congress 

can m.k:e a general,. it takes rapid and sec'Ul'e cammm1caticms to llBke 

h1JD. & good OOl!ll8llder • 11 

~swill in tact be the kl!1Dote at tbia lecture. ID other wmda, 

cammm1 caticms aecur.lti, 01" C<JelE 1 w1ll be its :ma1n theme and the ane I wish 

to ~ize. 

But before cardng to that part ot our history per~ a bit more attention 

' 

must be devoted to events and deYel..opnenta ot c:eyptana.1.Jtic sigD1f'icance 01" 

:lmportance during the period 1918 to 19116. B7 f'ar the moat spectacular and 

:lnteresting of these are tbe one which were so 1"ull7 and disastrousl.1' disclosed 

by the VBZ'ious :LnvestigatiODa cmclucted by the Anq and Navy very secretly 

mile World War II was stw. 1D progress18Zld both secretly' and ~ after the 

close o:t hostilities. The 1.Dvestigations were intended to asce.rta:lD why OU1' 

Arrq and Ba.VJ' forces 1D Bawaii were caught b7 surprise by the sneak attack OD 

1'eG"J. Barbor by the Japanese an the morning of' T December l~ 'Dle;y verenal.so 

1DteDded to ascerta.:l.D and p1n the blame an whoever was responsible f'or the debacle. 

I dan't th1rJk I should even attempt to give 10l1 rq perscmal. op:lDiOD OD these 

c~ questiana, which were studied by seven dif'rerent boazd.a witbiD the 

Senices and t11:1a117 'bJ' ~e Joint Congressional Camrd.ttee an the Investietian 

of the Pearl Barb01" Attack. I mentioned the latter 1D~st1sat1cm 1D rq f'irst 

~ 1"ctuze 11114 now I 7 lllld to 11bat I 1iban ~. i.-z'*W.lliooi '4la 

-.n •1 ..... -- 1 •• • wwwtldl16 :Iii!):::-:....• 1ta ~Septadber ~ 

1911-5 with secret heariDSs~but OD TO days subsequent to 15 Bcm!mber 1911-5 up to and 

:l.Dcl.ud:!Dg 31 May 1945 open hea:riDgs were ccmducted, 1i1 the course of which sane 

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15,000 pages of tes't1maa1' were taken and a total of 183 .exbibits received 

~JJw•t4MJ :lncideDt to an exanrfnatim of 43 w::ltnesses. l t!ie Carmdttee put out a f:l.Dal. 

cew¥.:..,~:·..,.. .l;o f'tL ~ t· 0et.L .; ...... ~~ ... ~.'lC.. ~of 580 1Bf8SA.~ :;;; E zr a set of' 39 volumes of test:IJIKmy mJ4 exbibit ~ 1]~~~. ~ 

-:··:· ~~~'i.t·~~~ . . ~ .,.,'fie Report "there,., wa. me 'bj":ti'le Ma.1or1t7 (signed by six Demccratic and two 

Bepubl.icrm members)~ am1. one bf the M1nor1ty (signed b7 two Republican members). 

!Lhe M1nor1ty Report was not nearly as lmg as that of the Majority but it 

brought into focus certa1D troublesme points which still form the aubJect of 

~~ acriman1oua discussians and wr:l t~ who believe the attack was "engl neared" lJ7 

--11ooeeva1.y....t.~~ ~.:.. w_ .. ~~a:t::-.... .. 

c· a~"" )N'IM. ~.....w ~ ..... .......,. ;... ,... ~ ..-11.. N.,-.... M •., ..... 

~ *-•a: :r=·~~ fact • tbat bath the lfa3ont7 am. M:l.Dor1t7 

~a conta:ln slowiDs tributes to the role plQ'8d b7 CCllINT before and dur1Dg 

C ~w. ""T;L:c.t J.,....ll , v.e.12; H...~J Qt19~ ~.s), our pa.rticipatian in World War II. In m;,y first lectureAI presented a brief 

extract in this regard takeJJ. tran the Majority Bepo:t f4 but here is' what 1;he 

~ 

_ ~~ '\ 6. Through the Army and Bavy 1.ntell::l.gence services extensive illformation ~. ms secured respecting Japanese war pl.ans and desisn,,1'7 intercepted ~ b .j/& and decoded Japanese secret messages, which indicated the growing 

-~~ daZlger of war and :l.ncreu1Dgly after November 26 the 1mm1Den.ce of a 

Japanese attack.. 

With extraord1Dar7 skill, zeal,, and watchfulness the intelligence 

serrtces of the Artq 81gaal. COl"pB and Navy Ottice of K&'V'Bl. Carnrunications 

broke Japanese codes and intercepted messages between the Japanese 

Govermnent and its spies and agents and ambassadors in all parts of the 

world rmd supplied the high authorities :lJl Wasb1 ngton reliable secret 

information respecting Japanese desisns, decisiO'f, and operatians at 

hane,, 1D the Ulli.ted States, and :lJl other countries. A:itb.ougb there were 

delays in the trrmslatians of mny intercepts, the :lntelligence services 

had f'um1Bhed to those h:tsh authorities a large number of Japanese messages 

which clearly :lJldicated the growing resolve of the Japanese Govermnent 

an war before December 7, 1941. 
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'l!1e MaJority Report DBde five m.1n rec••••.,,..at1mla,, of vhich the seconcl 

is of spec1al interest:4 

1bat there be a complete :lntegratirm of Arr1l:I aud Bavy 1Dtel.l:lsence 

agencies in order to avoid the p!tfal.ls at divided responsibility which 

experience has DBde so abundantly apparent; that u;pcm ef'fect1ng a UDified 

intelligence,, officers be selected..""Eor intelligence work who possess the 

background,, penchant,, and capacity tor suah work for an extended period 

of time in mder that they may becme steeped :In the ram:1ticatica& and 

ref':lnemea.ts of their tield anlmqpl.PJ' this reservoir at knowledge in 

e.val-uating •terial. received. 91.e ass:tgament of an otticer having an 

ap1>1tude for suah work should not 1m;pede his progress nor affect his 

pramotiODS. Bf.'f'icient intelligence services &i'e just as essen.t1al in time 

of peace as in war,, and this b1"aDch of our azmd. .ser91ces D111St al'W&P 

be accorded the b;1ortant role which it deserves. 

'I assume that due note of this recammendation has bemA ~ by the services 

but how tar it has been possible and practicable to 1.Daure that the reccmaenitatim/ 

has been ca:rried 01lt or will be I do not know. In this ccxmectian I th1nk it 

may be of intereit to cite what the distiDguiahed COll!lllll'lder wham I have a1.reaq 

:mentioned,, General Qaa.r Braclley 1 has to BaJ' OD this pol:nt: 5 

In their intelligence activities at .Al.lled Farces Headquarters,, the 

British ea.s1l.7 Olltstripped their .American colleagues. 'D1e tedious )'982"S 

ot prewar studies the British had cleYO'ted to areas tbroug'hout the world 

gave them a vast advantage which we nevei- overcame. 'l?he American 

Anq' s long neglect at intelligence tra.1D1.Dg was soon ref'lected by the 

:lneptne.ss of our 1D1 t1al undertald.np. For too JD&D¥ years in the preparation 

of o1"1"1cers for carrpnprKI assigmmmts,, we had overlooked the need for special.izatian 

in such activities as intelligence. It is um-ealistic to assume that ever'J' 

officer has the capacit7 and the incl1Datian for tield camnancI, Man1' are 

uniquely qualified for staff' intelligence duties and indeed would prefer to 

denote their careers to those tasks. Yet :Instead ot groc:mlDg qualified officers 

tor intelligence ass:t gnments 1 we rotated them tbrougb ccmventianal. dut7 tours 1 

nak1ng correspcmd1ngl7 little use ot their special talents. M:l.afits trequen~ 

found themselves assisned to intelligmce duties. And 1D same statiODS 

G-2· became a dumping groum\ for officers ill suited to 11.De oamnand. I 

recall how scru.pulousl.y I avoided the brand:lDg that came v.lth an intelligence 

ass:tgnment 1D my own career. Had it not been for the UDiq~ qualified 

reservists "ltbo so c~ tilled so lllBD1' at our :lntel.lisence jobs tbrougbout 

the w.r 1 the &l'IQ' would have found itself' ~ pressed tor cQlll1etent 

intelligence personnel. 

Have sme at you pandered over the reason wh1' an otticer who reaches 

the !dghest level at 001111U11Jd in an a.rm;.J" 1 ours as well. as in t ore1gn a.rmles 1 is 

p:I cal.led a "general otficer11 or •benera.JfT!j It is because he is supposed to have 

• 

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REF ID:A62832 
REF ID:A62832 

bad become known to Governor Dewey, it having been "leaked" to him by persons not 

authorized to disclose it. The information dealt with the tact that the u. s. bad 

~;._,~-~ 

been reading/\Japanese codes and cipher even before the attack on Pearl Barbor. The 

vital point which General Marsball wanted to convey to Governor Dewey was that not 

. only was the information which had surreptitoualy been given to Governor Dewey true 

~ ~, but more important vere the"'f'acts,pat (1) the war was still in progress; (2) the 

Japanese vere still using certain ot the pre-Pearl Harbor cryptoayatems; and (3) 

the u. B. was still reading the secret canmunicationa in these systems as vell as 

• 

certain other enemy cCllllllUDications. Therefore, it was vital that Governor Dewey 

first lecture tmt I might later give turther extracts from TlME's account and., ti" 

JI, ta-- ff...j ~;I continu:Slll the extracts/\.pa"Mcl cm-pases 3, h, aBd: 5 ot bbe f:!:I114t l:eftlil'•• here 

they are: 

..4neral Marshall had a long series ot bad manents after U. S. 

flyers, showing a suspicious a.tnount of foresight, shot down Admiral 

Yamaoto's plane at Boupinville in 1943· Gossip rustled through the : 

.Pacific and into Washington coc;kt.ail parties; General Marshall got to 

the point ot asking the FBI to find an officer ''vho could be DBde an 

e:xample of'. 11 (The FBI, fearful of' looking like a Gestapo, re:f'used). 

Once a decoder was caught in Boston trying to sell the secret. 

Once, well-meaning agents ot the Office ot Strategic Services ranaackea 

the Japanese Bmbaas~ in Lisbon, whereupon the Jape adopted a nev code 

for military attaches. This code resined unbroken more than a year 

laterTThe worst scare of all came during the 1944 presidential campaign, 

when George Marshall heard that Thanas :e:. Dewey knew the secret and 

might ref"er to it in speeches. 

Yet for all these fears, the Jape never discovered that the U. S. 

was decoding their messages . Even after the surremer, the Army still 

used Magic as a guide to occupation moves; though it had once been planed 

to send a whole army into Korea, Magic shoved tbat a single regiment 

would be enough. 

The letter, on stationery ot the Chief ot Staff's Office, bore a bol4 

heading: TOP SECRm', Fal MR. DEWEY'S EDS <lVLY. Candidate Tham.a E. Devey, 

his curiosity piqwd:, read rapidly through the first tvo paragraphs: 

-.Jj .!IL~.....,._ ,&.a ... J Jov.t;--~~ ,.:. c.:.A...-"?, ~ ~ ~)·. d2 .Jo.Ut:"" ~~J.. ~ ,Jl..e.e. ~ ~ ~~ ~~ ~.-w.r.F. 

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/i am writing you without the knowledge of any other i~ '~ person except Admiral King (who concurs) because we are ~l approaching a grave dilemma in the political reactions of " . 

Congress regarding Pearl Barbor. 

What I have to tell you below is of such a highly .... 1J J 

secret nature that I feel compelled to ask you either to 1:J 

accept it on the basis of' your not cmmunicating its con- "'J 

tents to any other person and returning this letter or not l 

reading any further and returning the letter to the bearer.61"" 

Tom Dewey looked up from the typewritten page. As he did the word 1 ~ crnrt;gs:raph,, a few paragraphs below, flashed into his vision like a red 

traffic 

it back. 

light. 

Colonel 

He 

Carter 

made his 

w. 

decision 

Clarke (in 

quickly, 

mufti), 

folded 

who had 

the 

flown 

letter, 

fran 

handed 

Qa.sh- ~ 

ington to Tulsa to catch up with Tan Dewey's CamJlBiSD, vent back, his 

mission uncompleted.~ o.. +~er.f>c.oe.ow..t.ct.>.k t~a.),.lT~~1M.: 

"'JOO BA.VE Mr wam. 11 It was September 1944. The campaign train 

rolled up through the Midwest, returned to Albany. A few days later 

Tan Devey received another visit from Colonel Clarke'!" 

The Colonel, again in civilian clothes handed over another letter 

fran General Ma.raba.11. The General had clanged his mbld somewhat: 

"I am quite willing to have 7CJ1X read what canes hereafter with the understanding that you are bound not to canmunicate to any other person any portions on which you do 

not nov have or later receive factual knowledge :tran acne 

other source than myself . • • You have my word that neither 

the Secretary of Qa.r nor the President has all1' int:lnation 

whatsoever that such a letter haa been addressed to you • • 11 

TBE LOCKED FIU:. This t:lme Tan Devey read on. Aa he turned the 

:pages, he became :the first nan outside the high COJlllBnd to knov the 

f'ull story of ''Magic" and what it waa accan:plishing in the lBr against 

the Jape (see above). The letter closed with a plea: 

"I am presenting this mtter 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." 

Tan Dewey locked the letter in his files, vent back to his electioneerins. Though he bad known before tmt the U. S. had cracked the Jap 

code, bad suspected that this informtion cast grave doubts on Franklin 

Roosevelt's role before Pearl Barbor, be held his tongue. The War De:partment 's most valmble secret was kept out of the campaie;n. 

MJml'ING AT A FUNERAL. Recounting this story at the Pttarl Barbor hearing last week, General Marshall. recalled that be and Tom Dewey never discussed the mtter in person until they met at Franklin Roosevelt's funeral 

last April; 11 I asked Mr. Dewey to come with me to the War Department and 

I shoved him current Magic showing Ja:panese movements. Bis attitude was 

friendly and gracious. 11 

Bad Marshall ever told Franklin Roosevelt of the letters to Devey'l 

Said Marshall: ''The President died without knowledge of it. 11 

SECREr LOSl' 

The Pearl Barbor Canmittee blithely tossed away one still-secret u. S. 

Govermnent weapon. George Marshall's letters to Governor Dewey (aee above) 

mentioned that the U. B., with the help of the British, bad decoded German 

as well as Ja:pa.nese messages, George Marshall begged the Caamittee to cut 

out these references • The Caam:lttee ref'used. 

Publication of the letters thus gave the Gernans their first knowledge 

that their code had been broken. It was also a breach of diplomatic ccmfidence with the British, who bad let the U. s. in on the secret on the understanding that it would be kept. 

q/"A~~~ ... : ;&.a:~~*'8.,. i"iMtLJltU., i.. d.:tJL.2.S"'~ ,,44 

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REF ID:A62832 

The Maraba.11-Dewey correspondence is so important in cryptologic history tbat 

I feel that the whole ot it should be included even 1n this brief' history. When 

the letter was written it was, of' course, TOP ~ and it was only under great 

bow 

preasureA.:S,- certain members of' the Joint Congressional Canmi"ttee • 1iae la.••*i&-

at1Qll ef iiM :c'.z'4i4le:d1 •Paa.Iii Banm: that General Marshall revealed~ ~ contents.if ~ 

«; 

,,. lf ilae la**• Thus>.-. la4i*er came into the public danain :not only on the very day 

... ~ ·~~ that Qene~l Marshall~ to place it in evidence - ).,'l!e le'Mier caused a. great' sensation :In the nevspape~a - but also when the 40 volumes or the Hearinga of that 

Committee vere published~ a"*8Hili*,. at 1i:ha eaaAUiae and put on sale by the Superintendant of' Documents of' the Government Printins Office. The disclosure of' the 

contents of' the Marshall-Dewey correspondence was indeed such a sensation that 

LIJ.l'.E magazine printed the whole of it in its issue of 17 December,1945, with the 

following introduction: 

,,I 

<;~L TOLD CAIDID\TE WE BA.D BROKEN JAP CODE I • 

During the 1944 election campaign General George c. Marsball 

wrote two letters to Bepublican CeDdidate Thanas E. Dewey, telling 

him that Army cryptographers had broken the Japanese "ultra" code. 

Thia fact was first revealed 1n a story by LD'E Editor, John Chamberlain, which appeared in LIFE, Sept. 24. Marshall's purpose, Chamberlain wrote, was to f~tall Dewey's revelation. of that fact in a possible attack on the ROOsevelt administration's Ja"P&nese policy before 

Pearl Barbor. The actm.l text of the letters remained secret until 

last week, when General Marshall appeared before the Congress icmal 

Canmittee investigating Pearl Barbor and made the letters public. 

Tbey appear below. 

When he lad finished reading the first two paragraphs of the 

first letter, Governor Dewey stopped because, as the Chamberlain 

article reportedt "the letter might possibly contain mter1al which 

had already cane tran other sources, and tmt anyway, a candidate 

for 'fresident was in no position to :nake blind pranisea." General 

.Marshall sent the letter back again with an introduction which rel.Mved the governor of binding conditicns. This time Dewe;y read the 

letter and a:rter much 'thowght and discussion decided not to mke use 

during the campaign of any information he previously had. 

t( So tar as I am aware it has neither been ascertained nor diaclosed,if' known, who 

save Governor Devey the in:f'ormtion. But it is a fact that as a pitriotic citizen, 

he acceded to General Ma.rsha.11 's request - he mde no use whatever of the vital secret 

inf'ormation during the camiaign or a:rter it. TIME'a account specifically states that 

Dewey ''held his tongue. The War Department 1 s moat val\Bble secret was kept out of' the 

-go.~~ .,-sa4tv( .9.. .r.~ ~ h Jh.:~. - \A/.'f:~ 

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REF ID:A62832 

!9P SE.m 

(FOR MR. DEWEY"S EYES OILY) 

25 September 1944 

M;y 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 Barbor. 

What I bave to tell you below is of such a highly secret mture 

tbat 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 nbt readillg any further and returning the letter to the 

bea:rer. 

I sbaul.d have pref'erred to talk to you 1n person but I could not 

devise a method 'that would not be subject to press and radio reactions 

as td vh:y the Chief of Staff' of tbe Army would be seeking an 1nterv1ev 

with you at this particular manent. Theref~, I have turned to the 

method of this letter, to be delivered by band to you by Colonel Carter 

Clarke who baa charge of the most secret documents of the War and, Navy 

Departments. 

In brief, the military dilemma resulting fran Congressional political battles of the political campaign is this: 

The most vital evidence in the Pearl Barbor natter consists of 

our intercepts of the Japanese diplaratic canmunications. Over a period Of years our cryptograpb people analyzed the character of the machine the Japanese are using for encoding their diplam.tic messages. 

Baaed on this, a corresponding 1111.chine 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 :f'Urnished the State Depa.rtmentratber than, as is popilarly supposed, the State Department provid:f,ng 

us with information - but which unfortunately 1111.de no reference whatever to intentions toward Hawaii until the last message before Dec. 7, 

which did not reach our bands until the following day, Dec. 8. 

Now the point to the present dilenma is that we have gone ahead 

with this business of deciphering their codes until we possess other 

cod.es, German as well as Japanese, but our main basis of information 

rega.rding Hitler's intentions in Eu.rope is obtained :f'ral1 Baron Osh:IM 's 

messages fran Berlin reporting his intervievs with Bitler and other 

of'f'icials to the Japanese Goverment. These are still in the codes 

involved in the Pearl· Barbor events • 

To explain further the critical mture Of this set-up which 

would be wiped out almost 1n an ilJ,stant if the least suspicion were 

aroused regarding it, the Battle of the Coral Sea was based on deciphered messages and therefore our fev ships were in the right place 

at the right time. Further, we were able to concentrate on our limited 

forces to meet their advances on Midway when otherwise we almost certainly would mve been sane 3,000 miles out of place~ 

We bad full in:tormation of the strength of their forces in that 

advance and also of the snaller force directed against the Aleut:lana 

which finally landed troops on Attu and K:l.ska. 

Operations ::ln the Pacific are largely guided by the information 

we obtain Of Japanese deployments. We know their strength 1n 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 tran time to time which they sustain 

by reason Of our submarine action largely results tran the fact that 

~ i ~io ~ ,_J-'Jk~·-eaaJ.,".a r1~~ liU- ~ ~~(.~ . .a).- \Jf:F; 

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REF ID:A62832 

we lmow the sailing dates and tbe routes ot their convoys and can 

notit'y our submarines to lie in wait at tbe 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 01L Ja1Bnese convoys, two ot which were 

caught, as anticipated, in his destructive attacks. 

You will understand from the foregoing the utter tragic cansequences if' the present political debates reprding Pearl Barbor disclose to the enemy, German ot Jap, any suspicion of the vital sources 

. ot information we now possess. 

The Roberts' report on Pearl Harbor had to have with:lravn fraa 

it all reference to this highly" secret matter, therefore in portions 

it necessarily appeared incomplete. The same reason which dictated 

tbat course is even more 1.mportant today because our sources have 

been greatly elaborated. 

As a further example ot the delicacy ot the sitmtion, sane of 

Donovan's people (the Q3S), without telling us, :Instituted a secret 

search of the Japanese Embassy affices in Portugal. As a result 

the entire military attache1 Japa.neae code all Ater 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 

1.nfornation source, particularly regarding the European situation. 

A recent speech in Congress by Representative Barness 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 ccm.clusion. 

The conduct of General Eisenhower's campaign and of all operations in the Pacific are closely related in ccm.cepticm. and timins 

to the in:f'ormation we secretly obtain through these intercepted 

codes • They contribute greatly to the victory alJd tremendously to 

the savings of American lives, both in the conduct of current operatians and in looking toward the early termination of the war. 

I am presenting this matter to you, tor your secret :Information, 

in the hope that you will see your way clear to avoid the tragic results •ith which we are nov threatened in the present political campaign. I might add that the recent action of Congress in requiring 

Army am Navy investisations for action before certail'l dates has 

compelled me to bring back the corps cCll!ll!8nder, General Gerow, whose 

tr.oops are fighting at '!rier, to testify here while the Germns are 

counterattacking his forces there. This, however, ~'! .. IJ very m:lnor 

matter c~ed to the loss ot our code information."(7' 

Please return this letter by bearer, I will hold it in my 

secret tile sub,Ject to your reference should you so desire. 

Mr Dear Governor: 

SECqND LE'l'ER 

'f 8P 8!.eftl!r 

Faithfully yC>urS I 

G. c. Marshall 

(.Fee MR. DEWEY'S EDS" ONLY) 

27 September, 1944 

Colonel clari.,,my messenger to you of yesterday, Sept. 26, ms 

reported the result of' his delivery of rq letter dated Sept. 25. As 

I understam him you (A) were unwilling to canmit younelt to any agreement regarding "not cammmicating its contents to any other person" in 

view of' the tact that you felt you already knew certain of the things 

o/..w,.. ~two ~IC••"~~~~ ~~r*'­ SwJ.... ~. s-..~ ti.~ -w.r.F. 

-CD. 
, . 

- - - - - - - 

REF ID:A62832 

probably already referred. to in the letter, aa suggested to you by 

seeing tbe word "ceyptograph, 11 am (B) you could not feel tbat such 

a letter aa thia to a Presidential candidate could have been addressed 

to you. bJ an officer in JJJJ position without the lmovleclge of the President. 

Aa to (A) above I am CIJ,ite willing to have you read what canes 

hereafter with the UDderataming that you are bamul not to cCllllllUDicate to any other person aD1' portions on which you do not now have 

or later receive tactual lmCJVledge fran acme other source than 11J8elf. 

Aa to (B) above you. have JJJJ word that neither the Secretaey of War nor 

tbe President bas any intiaticn vbataoever that such a letter baa been 

addressed to you or that tbe preparation or sending of such a cC111111UDication vaa being ccns1.dered. 

I assure you that the cmly persons who aav or know of the eziatence 

of eitl;ter this letter of rq letter to you dated Sept. 25 are Adm1n.l 

King, seven keJ officers responsible for security of militaey camunicat1ona, am JJJJ aecretaey who typed these letters. 

I am tr;ving rq beat to •ke plain to you that this letter ia 

being addressed to you aolel.1' an rq initiative, Admiral King 'having 

been consulted onl1' after the letter vaa clra:tted, and I am peraiating 

in the •tter because the m111taey ba-.rda involved are ao serious 

that I feel ame actian ia neceasaey to protect the interests at our 

armed forces. 

('!'he aeccmd letter then repeated substantially the text of the 

first letter e:xcept for the first two paragrapba). 

LIFE failed to note tbat the last two sentences in the penultm.te paragraph 

at the "F1rat letter" were '-itted fran that :parasraph in the "Seccmd letter," but 

t~re ia no ezplanaticm tor the anisaion~Perbapa it vaa aimpl.J for the sake at 

brevity, but this seems improbable. 

In JJJJ f1rat lecture 

I called attenticm to the tact that the acc01mt given 1D the TJMI article gives 

credit to Ariq ~lpts for providing the secret ccmmmicationa intelligence 

"which enabled our Ra.VJ" to win such spectacular battles as those of tbe Coral Sea 

and Midway, and to va;ylay Japanese CDl1Y0181

11 vberea.a the credit for the cCllllllUDicaticma intelligence which enabled our •VJ" to win these battles vaa produced by 

Ila.VJ' ceyptanalyata. Qie cannot blame the editors at TIMB for •king such a bad 

error because the source of the error can be traced d1rectl.1' 

~ 

toAMaraball'a letter 

itself'. Several Je&ra ago I asked by friend Col.onel Clar~vho bad carried General 

· Marshall' a letter to Governor DeveJ and who •s at the time a high level officer 
REF ID:A62832 

in G-2, haw such an error had crept into General Marshall's letter, and was told 

that the letter which had been prepared for General Marshall's signature a.id not 

meet with the General's whole-hearted approval and tl:at the General h:lmself had 

modified it.- Permpa that is boll the error to which I have referred crept into J;,. 

fl'° T ~ Q1e could hardly expect General Marsluall to be entirely familiar with 

the technical ceyptanalytic details involved in what he wanted to tell Governor 

Dewey, nor shaUld one critici11e him for not being able, in his very busy daya and 

lmder very heavy pressure ot events, to bear in mind or even to lmGlr about the ditgerences between the enemy systems worked upca by the respective and separate Azrq 

and Navy cryptam.J.ytic organizations. It is ot course possible, :l!deed it nay be 

important accanplishments ot the tvo services before and a:rter the Pearl Barbor 

,'1\ attack in the field ot cammmicationa intelligence, and muchGbas been written 

and is DOW in the piblic dam.in regarding those accmplishments, but fortumtely 

no teclm.ical details ot s1ga.1ticance have been disclosed. Hints .here and there 

are in abundance in the mny books alld articles that have been piblisbed by U. s. 

writers since the em ot World liar II; but more than hints ot the great 1Brt played 

by Camf.l' in U. s. military and m.val successes are to be found in books and articles 

published bJ ~rican officers as vell as by officera ot the beaten Japanese, German, and Italian armed forces. !rime does not permit citing 1D this lecture •DY 

' 
. -

REF ID:A62832 

of these hints or definite statements, but the following tvo are of particular interest because the;v concern the Battle at Midvay, which is considered the me which 

turned the var in the Pacific frail a possible Japanese victory to me of ::lgucn1n1ow1 

defeat: 

[~"·3] If Admiral 'fe.nwmoto and his staff"'were vaguely disturbed by the 

persistent bad weather and by lack ot 1Dformat::l.ca com:ern:l.ng the doinga of the eDem¥1 they vould have been trul.7 diama;yed had they Jmown 

the actml e~ situation. Post ..... r American accounts make it clear 

tlat the United States Pacific ll'leet knew ot the Ja11BD9se plan to invade Midlr81' even before our forces had sort::l.ed frail heme waters • .la 

a result of sane amaz::l.Dg achievements by American ::lntell::l.gence, the 

e11e1q bad succeeded :In break::l.Dg the pr::ln.c ipa.l code then :In use by the 

Japanese llavy. ID this way the enemy was able to learn Of ~ ::Intentions al.moat as qμ::l.ckly as we bad determined them ourselves • 

"4-- ')l- ""'"" ~ """" --""' 

The dist::l.Dguished American Naval histor:lan, Professor Samuel E. 

Moriacn, characterizes the victory ot United States forces at M::ldway 

aa "a victory Of ::Intelligence." ID this judgment the allthor tul.11' 

concurs, tor it is beymd the slightest possibility ot doubt that 1he 

advance discovery Of the Japanese plan to attack was the foremost 

a:l.ngl.e and :lmmed::late cause of Jaian's defeat. V::l.ewecl from the Japanese aide, this aucceaa of the enemy's ::Intelligence translates itself 

into a failure on our part - a failure to take adeqmte precautions 

for guard::l.Dg the secrecy of our plans. Bad the secret or our intent 

to 1Dvac1e Mid.way been cmcealed with the same thorouglmess as the plan 

to attack Pearl Barbor, the outcome of this battle might well !:ave been 

different. But it was a victory or American ::Intelligence :In a much 

bread.er aenae than just this. lqμall.y as 1mportant aa the positive 

advancements ot the eDeJQ" 1& ::Intelligence en this occasion was the ... n/ 

negatively bad and ::Ineffective tlmction::l.Dg of JapalJMS ::lntell::l.gence"f6" 

It 1a the aeccmd extract above which is of apec::lal ::Interest to us at the mcment, 

alld, :In particular, the portion which refers to "the negativel.7 bad and ineffective 

ca~ .. :functioning Of Japanese ::Intelligence." 'Die JQiU11111e a\@lor :la.Jl bit too severe on 

the JaJ8Dese intell::l.gence organization. I Ba7 this because their ceyptanalysta were 

A.ao..:.ti i: 

up aga1nat much more sophisticated cryptoayatems than they/\..-.., ar were qualified to 

solve. ID fact, even if they bad been extJ:emely adapt in cl"1Ptanal.ya:la it would 

have been ot no avail - U. s. high-level cammmicatima were protected by cryptosystems of very great security. 

_,_ 
REF ID:A62832 

This brings us to a phase of' crnt;olC>g' which is of' highest importa.Dce - the 

phase which deals with cammmications security, or CCJISJOO, and I shall can:f'1De IQ"-

~ .J.. ~ self largely t~ it~~Listorical background :In tae;t8• 8. ArlEcl Forces. '!llle background 

is a veey bread cae because it should :Include the background of' the developnents of' 

~£L) (?.) 

each of' the three cmpcments of' CCllSBCJA ~oaecurity,Atransmissicm. security, and 

(J) 

~ical security of crypta..ter1ala. But s:lnce time is limited and because I th:l.Dk 

you vouJ4 be mare interested :In the p'ba.ses perta:lnillg to cQPtoaecurity, I will anit ~ 

- ~.,... J.-*-~1 ~--f!.,.._..t;, 

references to the Ill••-. ~ tlle other two cmpcments. ftm. even :In limiting the data 

"' 

to crntoaecurit7, I will have opportunity only to give sane of' the h1ghl.ights of' 

the developnent of' the items that cmprise our,.crntanater1ala, 

~ mitt:lns ccmaents 

on the history of' the developaent aDd improvement of our techniques, procedures and 

practices, all of' vhich are extremely important. 

"Lsball beg:ln the story vith a definition vhich you vill f'iDl :In any good Englisb' dictionary, a def':lnitian of' the vord. "accident •11 You. vill get the po:lnt at 

what my seem to you ~1ght now to be merely' another at rq f'reqμent d1greaa1Cl1B f'rm 

the •:l.n theme, but if' it be a digression I thillk you will nevertheless f'md it of' 

' :Interest. Tbe word "'accident" :In Webster's Unabridged D:l.ct1cmary is def':lned as 

,follows: 

1. Literally', a bef'all:lns. 

a. An event that takes place without one's f'oresi.ght or expectation; 

an undesigned, sudden, and unezpected event. 

b. Bence, often, an undesigned arid unforeseen occurance of an a"t"f'l1ct1ve 

or 1mf'ort1.mate claracter; a mishap resulting :In iDJury to a person 

or daEge to a th:lng; a casualt7; as, to die by an accident. 

Tbere are further def':lnitions of' the vord. but what I've given is sufficient f'or our 

purposes. Bl1t why define the vord.l Wat bas it to do with CCJEBC T 

Dlr:lns our :par1;ic1pation :In World War II.,,the President at the tm1ted statea,accm-

-10-
~~ around the world. Be"journeyed other 

band, in April 1943, Admiral Isoroku Yamamoto, Commander in Chief' of the Canbined 

~ .. ~~°-- ~ k. 

Fleet of' the Japanese"'Ne.vy started out on what vas"Just an ordinary inspection trip 

~.)~~1\~~11"4A~ but it turned out to be a one-way trip for-,.,. '\Ae .\iai:Pal • :::::llis iea'o\ia w1H1 •PPQ\1Reei ia . 

<.f"i·s)J~ ~ Ka.~"b~ a£c.k.~ ~H~.).f~~~~"'""' 

--~ (t l\an official Japanese Navy communiqw: stating that the Admiral bad met a glorious end 

. ll 

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 acciden1(i'}i=J );;;... 

-~~ But sane bright personA it was the late Jimmy le.liter, when Mayor of Nev York City,..... 

~ J" who said that "accid~nts don't just happen-they are brought about.";,.;~ w~ ~ ~*'--4.CZ; '"""'~ ~ cV\--~ ~ 

Admiral Yamamoto did not die ~ by accident; he died because our Navy knew the ~ . 

schedule of his trip down to the~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 inter-

,., esting manner by Fleet Admiral William F. Halsey, 0. S. N., :_ f..:.o ~ ~ 

!i~ ~ ~:'-0" . 

I returned to Noumla in time to sit in on an operation that 

was smaller but extremely gratifying. The Navy's code experts had 

hit a jack pot; they bad discovered that Admiral Isoroku Yamamoto, 

The Commander in Chief' of the Imperial Japanese Navy, was about to 

visit the Solanons. In fact, he was due to arrive at Ballale Island, Just south of Bougainville, precisely at 0945 on April 18. 

Yamamoto, who bad conceived and proposed the Pearl Barbor attack, 

had also been widely quoted as saying that he was "looking f'orward 

to dictating peace in the White Bouse 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 •ke the interception over Buin, 

35 miles short of Ballale. Yamamoto• s plane, a Betty, accanpanied 

by another Betty and covered by six Zekes, hove in sight exactly on 

schedule, and Lt. Col. Thomas G.· Iamphier, 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 did.fl't want the Japs to know that we 

» ~ Admiral Halsey's stm, McGraw-Bill, Nev York, 1947, pp. 155-157· 

-..11-
' ' 

REF ID:A62832 

had broken their code. • • • Unfortunately, aanebod.7 took the 

story to Australia, whence it leaked into the papers, and no 

doubt eventually into Japan • • • • a.rt the Japa ev:l.dentl.y did 

not realize the implication any more than did the tattletale; ve 

continued to break their cod.ea. 

Mm.1ral Balaey' a Story ccmtaiDa a good mmy more iDatances at cryptologic 

aignif'icance and interest to us. Other authors, both .Amrican and Jaianese cite 

similar 1natances. QJ.e Japanese author states in categorical laDglBge that Japan 

was defeated because at poor C<JIDE on the part at the Japanese lla.vy and good CCJIDT 

m the part at the .Amrican llavy. 

Bu'b lest you get the impression that eneD11" intelligence agencies had no suecess at all with secret cammmicationa at U. S. Armed Forces, let me tell you that 

they did have sme success and in certain inatances, veey significant success. 

0 

There is not time to go into this scnevhat disappoiD.ting or diasillus~ing statemen.t but I can say that ae a general rule the successes vere attributable not to 

.:.., J{ia. ca 68 

technical vealmesses in U. s. ceyptoaystema but to their improper use" at certain 

OMCLlov-level ones, by unskilled,• improperly or insufficiently trained ceyptographic 

~ 

0 • ;to.. • • .• , .. ~_,.,._.~ .... clerks. I may as vell tell you right nov that thial\!:Bs been true f'or a great many 

years, f'or centuries aa.a •tter at tact, because as long ago as the year 16o5 

li'rahcia Bacon, w~o wrote the first treatise in Eragl.iah m the subject at crnt;ology, 

~I.a.&..~:~ 

~t.!JL.Mi~'.AeplWMll 

Thia Arte at CYJ?heriye, lath f'or Relative, an Art at Diacnber-

!Y.!; by auppoaitim unprofitable; but, as thiDga are, of' great use. 

For suppose that CuiJars were well 11111n'!l8ged, there bee MW.titudes of 

them vhich ezclude the Di~rer. But 1D rep.me of' the ravnesse 

and unakillfulnesse of th6bamiea, through vhich tbe7 paase, the 

greatest Mattera, are mny times carryed in the vea)Q!at Cypha,ra. 

When electrical am particularly radio tranamissicm. entered into the picture 
REF ID:A62832 

ie., 

from a study ot the procedures used. 1D"'tra.DB1Dission.A the direction am flow of 

Jr.a.ko~, 

,e1 wYP'\cMicma, the call sips of the transmitting am receiving atatiODB, etc., 

~ 

all without solving the camnmicatiana even if' they~ 1D cryptic form. P'ollov1Dg are 

'fiwa 

,._ 4GIJpJ.8 

t~ et extractal frm a document entitled Ge1'DBD O,peraticmal Intellipnce, published in April 1946 ,b7 the Germn Military Document Secticn, a Canbined 

British, Canad.1an, aDl u. s. Staff: 

(:~., ~~ ,,.._ ~M1"'1"") ,t$igr:ta1 intelligence,. w.a a chief source of information. in the 

Germn A:nr:f. In the eastern theater, where there was offensive 

warfare primarily, the signal intelligence service was well-organized vith well-defined purposes, efficient persomiel, and adeqmte 

equipnent. In the com-ae of the campa:lgn, it w.a reorganized to 

exploit to the full.eat the success already u:perienced, a.lld., by 

1943, there existed a complete and smoothly tunctiming mchine 

sufficient to meet all demands.- Cf· BJ ~-- ;IF ~ ~ ~ "7'lr 

Moat of their sigaal intercept success came f'rm low echelcm. 

traffic. Armored and artillery radio nets passing operational traftic 

vere followed closely and vere one of the chief sources of signal 

intelligence. Artillery radio nets vere given first coverage priority. 

Apart f'rm messages intercepted in code or in clear, signal procedure, 

peculiarities of transmitting, &Dd cl:aracteristics of Allied radio 

operators proyided ellOl'IDOWI assistance in helping to evalmte sigDal 

intormatian. Tbe Germns noticed tba.t call signs vere often the same 

for a unit over laag periods am that even frequencies rem1Ded unchanged for veeka at a time. { t· t .) _ 

, r "'1ch tactically :Important infOl'!IBtian vaa drawn ~ the eneJl!r'' ~ Air Force 11aiaan net. It .ws assumed that an 11J4ependent net aened 

I all Air Force 11aiaan j)fffcers •ttached to tht!- various headauaftera 

and mce ane of these'statiana had been pic:keil up and icle!a:t!'fied, it 

~ could be used j;o..1f"race .all other statiQJlll ''Over a cana1¥ftble area. A~ Force :Pdfic dealing vith banb~ targets was 11P*rcepted b7 

Air tf"'unita, and was sent~ liaison chamu!d-. to Western 

=-~CaamaDd. Pran here, jJrir a network goi.n.g4own. to division.a, 

;7"""~0rmtian YOUld be f').a'ihed to all Army~tian headquarters. l 1'eceiv1Dg aeta at all ~la, including divia , vere tuned 1D cmLtinually to this bredcast frequency." (P. ) 

,,,.,. ~Im,port!Dce of Sip.l Intelligence During the B'ormndy Invasion: ~ 

. Il.lring the invasion, the G-2a in the West drew about 6o per cent 

of' the operatiomlly important informtian fran signal intelligence. 

The remining Ito percent was derived frm all other fields of' intelligence. The ammmt of intormatian decreased during the months of 

mobile warfare. During the retreat, although lihe possibilities of 

ob14ain1Dg inf'ormtion became leas frequent, the amount of intormtion 

frm aigaal intelligence renained hiBh· Moat of the in:f'ormtian vaa 

deduced fran the organizatian of enem;J radio traffic networks, f'raD 

decoded :messages, and frm the radio nets of the erieJQ' Air Force 11&-

iacm. officers vho vere attached to ground trc>Opl. Based upon this 

inf'ormtion the evalmtian center of' aigr:tal intelligence often came 

to concluaima which, at first, sounded hypothetical to the operational cCllllBl1C\ &Dd vere therefore doubted. In 90 percent of all these 

cases the events verified the signal intelligence :lll:rorDBtim so that 

eventmlly more .credence vaa given to its cmcluaiona." (t.a.2.~ 

-13-
REF ID:A62832 

A great llBIJ1' elCBlll,Plea of :Intercepted messages ot tactical content are cited 

:ID the aforementioned document, which 1a replete with 1n:f'ormt1on of deep interest 

although the document vaa orig1.Dally 1Baued with the lowest security classification 

then in use (U. S. "Beatricted"J Britiah-canadian "ll'or official use only".) I wish 

there were time to quote at igreater length fran this useful brochure. 

Caning directly nov to the history of the developaent ot our cryptcnater1ala 

themselves, I hardlJ' need reiterate what wa.a po:lDted out :ID previous lectures aa 

to the profound effect ot the advances 1n the science and art ot electrical ccnmmicationa 1n the 20th Cent:.m"J. '!'hose advances had a direct eff'ect upon military 

cammmicationa and an indirect effect upon military ceyptolOQ'. Batld.-operated ciphers 

.&e.:U~-- a-cl.~ and, ot course, codebooks became almost obsolete A""'11a the need tmfseaterA speed of 

~~;_~ . 

ceyptographic operational\to mtch as much as poBBible the very great increase 1n 

. ' 

-~4'15-
REF ID:A62832 

ll'DtU the advent ot electrcm.ic cipher mahcines most crnt;ograpbic apparatus 

c~ ..... f,a1v 

and devices were built upon or aroundl\circular rotating members 4Jt cipher 

A~~~6' wheels, cipher di aka, etc. pa ....,. eari&e•t fll eJ •e the ea.rl1est~p1cture ot • 

a.~ 

such~ appears 1D a tr.t1ae b)' an Italian crntoJ.ogiat named Alberti whose 

Trattati 1D Cifra. .a written 1n Rcllle about 1470. It is the oldest tract cm 

cr;yptasra.Pi7 tbe world now possesses. Here's a photo of Alberti' a disk (Fig. 6), 

but I wantt take the time to ex;plaiD it except to 881' that the digits 1, 2, 3, 4 *° e.Jll, ~ ..at&...fi"""" Jo Kt... f-X" 

were used to encipher code groups and ,.that the letters at the cipher or 

,.,.- ~· alphabet were 1D mxea. order. In Porta's book, first publ.iabed 1D 

1563 1D Ba.pl.ea, there appear several cipher diska5811A 1D the con which was 

given me as a g1i't b)' Colcmel Fab18D thq areA • 1D wmtd.ng ccmditicm. Here is a 

,S.a~ ot ane ot them (ftg. 7). l:D this versicm the device uaeli aJDibola as 

cipher characters. .And appa.ren:t~ nobod1' tlwu111t 1J1> ~ much better tor a long, 

MfV 

long time. It seems, 1D tact, that not cml.7 did nob~ t1Wlk "~ new or even. 

acme hpovementa cm the orgiDal Alberti or Porta di+ those who did 8D7 

thinking at a1.l on the sub~ect ~ "invented" or "re•iDvented" the same th:l.ng 

a.pin, and tbat happended repea.tedJ.¥ 1D successive amarationa. For inatance, 1D 

w: 

Lecture Bo./ of this aeries JPU were BhowD a picture at the cipher disk "invented" 

'b7 MaJor Albert MJer, the first Chief Sigaal Officer ~ :bhe u. s. ArmJj who 

obta1ned a patent on his 1zmmtion in 1865. Here's a picture ot the patented 

~~... -w.~oa9.. 

disk (Pig. 8) and th~ expl.anaticn ot ,..," (Fig. 9) • ,_ You ~ remember tbat 

' s1p•1 men of the Conf'edera.te Signal Corps mechan1zed the old Vigenere Square and 

put it out 1n the fm:m ot a cJ1.1Dder (see J.l'iga. 13, 14 and 15 at Lecture Bo ... IV). 

'Dle ci:pber disk used by the Sigaal Corps at the U. S. Anq during the decade 

ow~.:.~-- a..o A.~ A..v 

1910 to 1920, that is, during the period iDclwling World War I, was noth1ng but 

16 " 
REF ID:A62832 

white celluloid ~tion at tbe or1g1Dal Alberti disk ot the TI.ntage at 1410 

IJJ 

(except tbat it._.. even siJl,pler tbJ61"'its prosenitar,because in the latter the 

cipher alphabets produced were mixed aJ.pba'beta whereas, 1D the S1gaal. Corps 

d1at1 tbe ciitiezo &1.pbabeta are s1m;ple reversed standard sequences. Ve all kaow 

that it~ takes a prettJ' long time to get a patent tbrousb the as•• 

.rl•* 19• al 411ae U. S. Patent Ottiae, but 1D l~ the ancient device WBB 

PL~ 1D 1524 'b7 S. JI. Huntington/ (Pig. ll). llere JOU can see a giw.t 

:lm;provemmt over the Sigaal Cor,ps version--& blJmk is added to both sequences tao 

~ ... :.~ -i wv-nl. ,4p-.u.. 

tbat the space between wm"ds could. be encipbered. f"H1 as JOU han lea.med, is 

a fatal weakness 1t seen ill the cipher text; 1n the BuntiDgton device the spaces 

'between words woul.cl be enciphered but the cipher text would have space signs, 

German Ba.ti~ Socialists were banned as au organ1zat1 the Bazis used this 

w.riation ot the old d1Bk--1t had the 10 d:lg1ts on both tbe outer and the 1DDer 

sequences tor enc1pb.er1Dg distts (Fis. 12). 

;,..,.~..::ti..lSir Charles Wheatstone, who~- sane time betore l.8T9~a cipb.er device which 

-rwa. 

he called a,.tz.ntograpi. lie described it 1n a. volume entitled /a1e Scientific 

Papers ot Sir Charles Wheatstoa.!(f published 'bJ' the Phpical SocietJ' ot i.omon. 

llere is a picture ot Whea.tstan.fs dertce/ which is 1D '1111' ~ecollectian (Fis.ia). 

17 
REF ID:A62832 

What Sir Charles did wa to mke the outer circle of letters (tor the pl.a.in text) 

· cam;priae the 26 letters at the alpbabet,pl.ua ane additional character to 

Jy 

represent "space." ~e imler cil'Cl.e1 f'or cipher equival.mta, containp ODl7 

~ 

the 26 letters of the al.pbabet and these ~be disarranged in a m'xed sequence. 

A.A..~aJl&­ TVO baDda 1 like the hour and minute hands of a clock, were provided,,. under control 

at a ditterential sear mechan1• ~ 

1 so tbat ~ the long or ''minute" lllll1d. 1a advanc;ed 

to make a car;alete circuit of the letters on the outer cil'Cl.e fll letti•a • tlae 

:e&ee ,,, tAe Cl~CCI Ir the abort or ''houz" hand advances one apace or segment 

In :rig. 131 tor 

~.ti:..., ~,=Ac· 

exanq>J.e, the pl.a.in text letter 0 is represmted 'b7 the cipher letter A,,.. It 

upon tbe mlzed aJ..phabet used in the 1DDer circle and the 1Dit1al positions of the 

During World Var I, same time :l.D 19171 the British M!lq rescusitated 

18 
REF ID:A62832 

Wheatstone's cryptograph &Dd :ba;pl'Oved it both mechanicalJ.7 and crntoe;ra.pb1cally. 

Here' a a picture ot the device (Fig. 14 ~ 1D which it will be seen that there are 

DOV ncn1.onger the ''minute" &Dd "faur" hand.a but a siDS].e haZJd. with an operling 

tt:.. ~.:..U.QfA...~ or window that s:lmultaueoual.7 d1ac1oaes both the plain :t8* and ,._ciJJb.er letteraA' 

YJ«...lfjltc.....;,+f....cl" .. ~~ ~~·:i-~-- ...... ~.....la...,..;&;.. ~-- imler circle ot 16 isf.~sed• me 1r aga.1Dat~ ii11• mer 

circle of segment Jwhich are made ot a a'Ubstance qK>D. Vhich letters :mq be 

written 1n pencil or 1D iDkJ In this iq)rov'emant on the oria1Ml Wheatstone cleri.ce 

both aequmces at letters are now :m:lxed aeqwmces. lllld.ng the outer circle 

also a m1xed seqwmce added a c011Siderable degree ot security' to the cipher. 

When it was proposed that W. tbe Allied armies use this clev1ce for field cryptoc01111Pm1caticas and its security had been approved by British, French, and 

.American c;rnrtaloSists (both at GHQ-All!' and at W&ahingtcm) an opportunit7 to 

agree or disagree with the assesament ot these crn>taloglsts was glven me 'While 

is 1 1 still at till Riverbank.Tab 1.-19'11 I was abHa to show that the ~ed 

Wheatstone crn>togra.ph was still iDButticientl.J' secure for military purposes 

and the clevices, thousands al which had been manuf'actured and issued, were 

withdrawn. U 7011 are interested in the method at solution I used you v.lll t':lnd 

it 1n Rlverbank Publication Bo. 20, entitled Several Machin ""' e Ci@ers and Methods 

- ,.....Q..,..:t i,a:a. 

tor their Soluti~. A better metbocl of solution was cleri.sed by me,<w 

~? rs ilsPUr. 

S0me.. 

,...--. }'eBZ"S l.-:l;er, and aJ.Dost 'b1' sheer good fortune, I lea.med. tbat a cipher 

machine was in the museum ot' a aw:s1n ama.ll town in Connecticui.t named 

i::' 

l(emden. I was interested and wrote to the cT ot the museum, requesting 

that he lend the dev:l.ce for a short period to me as principal crnrtamJ.7at ot 

the War Department. Imagine 117 astoniabment and pleasure when I 'IDJ.P&Cked the 

+'"" ·~ ,... •• :t1i' 

box"-* •, and f'omid a device, beauti~ ma.de and encased in a fine maho~ 

19 ----------- -
REF ID:A62832 

case, vitb its inventor's ~' Decius wad.north, and the elate, l.8l.T,,ensraved on 

the face ot the machine, *1ch wa.a nothing but another version ot the Wheatstone 

. ~Al\,ll.r~~μCryptograph9. Here's a picture ot it (Pig. 15). ~1~il•• the model was Ede 

'bJ' Bl.i Whitney. MeclumicaJ.11 it 11ILB s1m1ar to the British :mod:!f1catica_,except 

tbat the outer sequence :b84 33 cb&racters, the 1m1er 26, so tbat the lliff'erential 

gear instead ot opera.ting on the ratio 21 to 26 VBS now on the ratio 33 to 26. 

c~ ~~~ ~ .nJ ~.i~~ 'Dius,"Decius Wadsworth,,..• Jl•1noaa ..,_,,. C9*=-a1. ... first Chief' ot ~~ _.. 

aa 1su;:lsue al .,, W.1 tn,., had anticipated Si• Cbl'CQ8r Wheatstone 'bJ' over 6o 

JSl"• 1D this iDTeDtion. He also anticipated the British ~~ b7 a 1lhol.e centU17 

,., 

in their mod1.t'ication ot Wheatstone• s origiJJ&l, because 1D the :ad.north clevice.:11 -R»o ... 

there was ~ cae hand and both alphabets could be made mixed sequences. 'l!lis 

is Teri cl-.rly shown 1D J'ig. 16 as rep:rda to tbe outer sequence,and I believe .Htc..t" 

. ;L,,~~ ~ ~ 1£,...r~ Jrot.. ff.a~.;;..:. 

the imler one could also be disarranged but A I am DOW' not sure as to this point. 

I returned the clev1.ce a good JIBD1' J'e&l"S ago and it is DOW on displ.q 1D the 

BU. Whitney Boan at the New Haven Historical Socie't7'• Museum. 

'Die next de91ce I br1Dg to J'OU1" attention issm>wn 1D J'ig. l.T, a device 

invented b7 a French Arlts7 reservist, Ccprenaant Ba.zeries, who tor sane l.O ;rears 

~~U.-•··•&••~ ~ tried to get the J'reDch Arrq to adopt it. 'lie WU rot anpcesat, .,,in.cJ.uded 

,... "~ ~.-..._i1r~·.,..., 

a description ot his device,11h1ch he calJ.ed hisA"crnrtogra.:pb.1c CJ"l~," 

1D a book published 1D 1901 1D Paris.~ He had, howeve.r,l\deacribed ~ his device 

1D an article entitled "Crnrtograpbe ~ 20 rmJdeJ l es--alpbabets (25 let# pa.r Ji;:. 

alphabet);' published 1D J.891~ ID this device there is a central aha.ft ca which 

W' ~ , Les chiftres secrets devoiles. 

16 CcgJtes Rend.us, Marseilles, Vol. XX, pp. 16o-165. 

20 
REF ID:A62832 

can be mounted 20 numbered disks on the peripheries of which a.re clifterentq m1nr 

eo-.-.k 

al.pbabeta of 25 letters each. 'lhe disk.a ue asa•hled "' *ts h•ft" 1D same A . 

~~~~ pn:t•.._~~~\o"~:....~~~.).~ 

prearranged or key sequence"' 'lhe tirat 20 letters al the pla1n telCt al a message 

~' aa aeea :In ns. lT (Jl! Sills ~ s "I am :lndec~e"l;kk ~ c».&. l«e-"4r-e..J.. "...,jg ~...,_ .ao.t<..:t ~ ~ ....... ~c.-ie ~j 

and as cipher text cm.e J11Q" select flD1' one al the al:ib.er 24 Fat letters, 

" ~~(--.Lo-~~ ~ (_~t~~ which are recmded,\ 'D1eD the next _.... 20 pl.a.:ln-tezt lettera,...a al.i~ etc. ~ 

o.j_-&.c....~ 

To decipber a mesaase one takes the first 20 cipher letters, al.1SD8)t them 

wt6~ Aon the device, the disks hav1Dg been assembled on the abaft 1D accordance with: 

the prearranged or lte7 sequence and then ._. t'm"DS the whole CJ1~ search1Dg 

O'tC. G·-L 

tor a rov al letters which torm 1Dtelliglb1e tart. !lhere will be,..cml.7 one such 

raw, m:ul the plaiD-tezt letters a.re recorded. '!hen the nezt 20 letters ot cipher 

a.re aliped, etc. 

~ 

~ ~N,4nother French ceyptologlst, the Marquis de V1Brls, ,..showed how 

messages :prepared 'b7 means ot the Ea.zeries eyl1D4r1cal cipher could be ¥oivea~ 

- M11.7be that is 'Wb1' Ba.zeries wasn •t too successful. 1D his attempts to get the 

French A:rtq to adopt his clevice. Bllt 1D the U. S. there were appa.ren~ mme 

who encomiterid either wbat :Bazeries or de V1ar1s wrote on tb.e subJect. capt. Parker 

Hitt, U. s. Artq, wham I have mentioned 1D a previous lecture, 1D 1915 invented 

a dev:l.ce based u;pon the 'Ba.zer1.ea principl.e but not in tb.e torm ot disks mounted 

upm a central Bhatt. Instead ot disks, H:l.tt's clevice used slidiDg strips and here 

(r~·1t), ~ is a picture ot his Verf' first :model"\ilich he presented to me same time :In 1923 _ f 

or 1924 (Fig. 1.8). But I lea.med about his clevice acme tille 1D 1917 while still J#' 

·le 

at Biverba.nk, and solved one challenge message put up 'b7 Mrs. Hitt, a Rl.verbank !. j ~ ~~ ~ ,.. .• ee••%~0fa!~ ~--,,.,-\ell..~~ guest tor a clq. /\.I dicfD •t use miytbing like what I could or m:lgbt have lea.med 

~~~~~~-· , ' 'tJI L!l#'t de chittrer et de decbittrer l.es d!P!ches secretes, Paris, lllD3, p l.00. 
REF ID:A62832 

to Mta. I'll+• ) because at that time I hadn't yet cane across the de Via'r1s 

book. I solved the messagew gu.ess:l.ng the k8J' Mrs. B:ttt erJl)lOJ'f!d to arrange 

her strip alpia.bets. She wa.sn 't wise to the quirks of :lnexperienced ceyptograjpbic 

clerk.a; she used BIVERBAmC LABOBATOBIES as the key", just as I suspected she 

would.. !lhe device she brought wtth her was an improved model: the al:plm.bets 

AJ,..--~~ 

were on paper stripslll.gl.ued to strips ot wood, as seen 1D Fig. 19. 

capt. B:ttt brougbt his device to the atteBfdonoof the then MaJor Mauborgne, 

wham I have also mentioned in a previous lecture and 1mo was then on du"t7 1D the 

Ottice ot the Chief' Signal otticer in Wash1ngtcm. !l!lere is acme question as to 

1lbei:her it 1.a Hitt 1mo ~ A 'brought his device to Mauborga.ell attention; Ma.uborsne 

later told me that he had 1ndependently conceived the 11mm.t1on Blld,moreover, 

had made a model using disk.a instead ot strips. I have that m.ac!el, a present 

A,ii....., ot..~i..... 

traa General Mauborgoe DIBDJ' yea.rs later, • It is DBde ot trsn, veq hea"17A an 

the peripheries ot the 41 $ 9 flll which he had engraved the letters ot his own 

apec~sfJd. alpbabets. In 19191 after DJ1' return to Riverbauk. tram '1113' service 

~: .. ~(~ 1n the .AEF, Mauborsne sent Riverbank the~st 25 etters)ot a set of ... 25 -

~ messages enciphered 'b1' his device and aJ.pbabets. Be also sent the same data 

to M&Jor Yardl.97, in G-2. Robocq ever solved the messages, even after a good deal 

ot work and even arter Mauborgne told us tbat two cc:msecutive words 1D one ot the 

. challenge messages vere the 'W01'da "are you." MarJY yea.rs later I found the reason 

tor our camplete lack ot 111JCeesa, when I came across the p1.a.1n texts ot those 

, 

rwa-'t, ~~·ia· f'~A,,.:,.. ~ £t M~.....o ~-·a ~ messases in a dusty old :tile 1DA the otf'ice ot Chief' Sisnal Otticer. Here is a 

' 

picture of the beg;lnn1n~ot the first s:lx messages (F;l,g. 20). Ma.uborgne,_ vhen 

I chided him on the unfairness ot his challenge messages, told me that he had not 

prepared tbem himselt--he had an1~~or Fowler vas his nmae, I still 

22 
REF ID:A62832 

remember it!) prepare them. In our struggles to salve tbe ahallenge messages ,oe.. 

had assumed that they mul.d conta.1.D the usU&l. sorts of W01'ds :f'OUDd as the 1Di tial 

words of m:llitar.Y' _.aagea. It vas the cam;plete :f'ail'Ure by Rl.verbcmk and a-2 

..., 

to solve the challenge messages that induced Ma.ubor19'e to go ahead with the 

developnent of his device. It cuJ m1nated 1D what became kDowD as Cipher Device, 

Head of the Department of Eagliah at the um.versitJ' of Chicago) 'brousht to '1111' 

attention a photostat of a ho1ogra.pb1c :manuscript 1D the ~ A collecticm. of ~eracm. 

Papers 1D the Library of Congress.. It consisted of tvo pages entitled f"Jh.e 

Wheel Cnmer" and here is a picture of the seccm.d page (J'ig. 22) ahow1ns Jetterson's 

basis for calculatiDs tbe number of permutations aff'Ol'ded b7 the set of' 36 wheels 

an electronic digltal caa;pu.ter--tor the total number is astrcm.anical. 1D size. 

Jettersan anticipated Bazeries by over a cmtur;y,G>.M4l ~ H~-t'l~~ 1d' ,.Q. ~ A. ~'Ct~ "--~· It soon became apparent to bot.h ...- Arlq' and .. Navy crJPtologists tbat a . 

great increase 1D cr;yptosecuri ty would be obtained. 1:f' the alpha.beta of tbe M-911-

device could be made~ ~ 1Datea4"'1aefn11:1!11111.. "~· There began efforts 1D bath 

services to develop a practical iDatrument based u;pcm this pr1Dc1pl.e. I wan 't 

-take time to show all these devel.opnents but ~-the f'iDaJ. f'orm of the Arlq 

Strip ~ipber Device Tne, M-l.38-A (Fig. 23.) • !l!l.1s torm used an aluminum base 

.,./_ into which cbazmels were cut to hold ~ card.boa.rd strips of alpbabeta /ih1Ch 

~ .. cCNU be Bl1de-.s11.7 w1tb1D the channels. It llllll'/I\ of interest to JOU to l.ea.rn tbat 

23 
ot hf.sh speed and security. 

'l!lus far we have been dealing with cipher devices ot the so-called ''hmldoperated" 'Qpe. lfane at them can really be ccasidered as beiJJg ''Jlllchines," that 

is appa.ra.tus e.aq>l.oying mec'b11111 cal.ly-iz'iftD :members upon which alpbabetic sequences 

produced. We cane DOW" ~ ~ tJpe.s ot a.ppa.ra.tus which can be called ~ DB.Chines, o-cL. O?\&. 

. . ~-c.~~ 

such /t8 tae 1 1 sh~ in Fig. 24. It is called the KmBA, the nmne ot its 

Geim.n inventor, who UDfortUD&tel.y cmmi tted suicide a few yea.rs ago, peztlg1s 

~~~'tf.:.~~.A;.~F because"• fnU ea 110 mke a success el aia '8Yell.Ma. '° ~~~~- 'lhe KrJba has a tSsecl 

semi-circle at letters apinst which is juxtaposed a rotatable circle ot letters. 

Both sequences at letters can be made mixed al.phabets (the segments are removable 

and interchangeable on ea.ch sequence) • 'l!le b1111dle at the right serves to w1Dd. a 

rather poverful. ea&ei steel" ~ spring which drives the rotating member an which 

the letters ot the ilme'r ci:rcl.e sre mounted. In Fig. 25 can be seen sanethirlg 

at the imler mechanism. 'l!le large wheel at the risht bas seQmmts which are open 

or closed, depending u;pcm the "setting" or key.- This wheel controls the 

angular displacement or "stepping" of the circular rotating platfmm u;pcm which 

the 1etters ot the cipher sequence are mounted. !lhe irliti&l juxtaposition of the 

24 
.... 

• 

REF ID:A62832 

at the 1m1er or movea.bl.e alpbabet asa:tnst the outer or fixed cme as well as the 

cau;positicm at these alpbal>ets is governed 'b7 acne key or other prea.n'BZlSemeDt. 

'lhe cipher equivalents must be recorded by band. After eac~enci'Jiherment, the 

button you saw ~ the center ot the panel. :In ~e preced:lng)ns. 24) is pushed down' 

• 

the imler wheel/\ad.vanced 

IA) 

1 ~ 

1 2, 3, 4 ••• ~ steps, depenc31n; cm the key, 

and the next 1etter is enciphered, etc. 'lhe pictures I've ab.own )"OU appl.J' to the 

latest :moc1el. of the Kr1ha; aa regrada the first model, wh1ch came cm the market 

sanetime :In the lSQO' l!J a German mathematician produced an 1J111naaive brochure 

abow1ng how JllLD1' diff'erent permutaticma Bild comb1Dationa the machine a.t'f'orded. 

Here's a pioture of a cou;pl.e at paps ot his deasertation (Fig. 26) but even 

1D those clap prof'essioml cr.ypta.mlysts 1rere not too .. JJqpressed by cal.culat~cm.a 

of th:!,a sort. With modem electronic cCllPltera such cal.culaticm.a have become 

of even leas significance. 

Let us now proceed w1 th sane more cOllq)].ex and mare secure :machines. In 

this nmct sl.ide (Fig. 2T) you see a machine wh:l.ch :represents a rather marked 

' 

:J.m;provement by a Swediab cryptographic firm upon the ones shown thus far. It 

is mechanico-electrical macbine des~ea. as '1-ntC>Gl'Bphe B-2l.l.. Here for 

the first time you see a cr;yptograpbd!c machine provided w1 th a keyboard sim11 ar 

to that cm an ord:lnary t)'PeWl'iter. Depressing a kq on this keJbOB.rd causes 

a lamp to 1iQbt under cme of the 'letters on the 1nd1cat1ng back above the keyboard. 

' 

At the top ot this ma.chine can. be seen four ':rheels :In front of two rear wheel.a. 

'lhe four front wheels are the 1'otat1.ng elements W.ich drive the two rear wheels~ 

the latter are electrical cc:manfletora that serve as connection-ch.angers to change 

the circuits between the kqs of the keyboard &Dd the lamps of the 1ndicat1ng 

boa.rd. '!here iBD 1t time to show JUJU the. :lnternal "IDl'lls Wich ccmtrol the rotating • 

25 
' 

REF ID:A62832 

elements and c1pher1.Ds wheels (you w11l aee them later) but I must show you 

the next step 1n tb.e 1mprovement ot such cr,yptogra.pbic JIBChinea, wbich :made it 

possible to eliminate the tedious job ot recozd!JJg,"iliit ~ hand 0.11 pa._per, the 

results ot encipbement or decipherment. 'Jhis was done by mean.a ot a. printing 

mechm:liam 'Which RS a.asociated vi th the crJPtosra.pb.ic llBChine. Here is a. slide 

(Fig. 28) which shovs the a.ssemblJ"-•the :B-211 connected to a Read.DgtonA 

~ 

tJ:pew:riter, 

modified to be actuated b;y :f.nqJUlses frail tm cr,yptograpbic machine. ot course, 

it wa.a natural that/ the next step would be to make the :recordins me~am 

a.u integral pa.rt ot the cryptosrapb1c machine/. 'Jhis you ca.n see 1D the next slide 

(Pig. 30), 1D which tbe tour nta.ting members referred to 1n cODDect10.11 w.itb 

Fig. 2T and 'Which c0.11trol the tw cammu:tators also men.timed in connection 

, £e..a .ID _ ,, n _ n II 11 I\ 

~~ GO A1'Ul.r ~ M. ~ ritb.""148• are clearly seen. The slide-bar mechanism at the risbt_.,,eontrols 

~ the cliaplacements ot the ~t:l.Ds wheel in frallt ot ~ aM.tle -- Jll!ebsnj m BDd 

causes the proper letter to be printed u;pon the m.ov1ns pa;per tape seen at the 

front ot the machine. 

Bow we cane to the DextaDd a verr iJzCportarlt developnea.t, 0.11e f'irst 

\~ conceived by a European irmm:tor, iEj. was f'ollowecl soon. thereafter_, but 

independentl.J', by a.u .America.u m.ventar~ In this ad'98.11Ce the cirau1ta between the 

kqs ot the keyboard a.nd the lJmq>s ot the 1nclicatins boa.rd are V&J,"ied b7 electrical 

~ ~~coU-L 11~ ~ILctUA.&di-~~ u u ,, 

~odurtrg members called stators. In Blrope the first ot such machiDea put upaa 

the mrket f'or purchase by- 1UQOD8 desiring one is shown in the next slide (Fig. 31.). 

'Jhe machine 'RB a.ppropri.a.tel.J" maned the EGMA--for solution ot messages enciphered 
REF ID:A62832 

ID Fig. l at the left (labeled I) is se• the macbim vltb the top cOftl' plate 

closed. At tbe front ia the Jre7board; aba9e it the :lJJdicator boaz'd, ccmsiatU!g at 

J.am;pa UIUJerDeath glaas d:laka 11lX>D vbich letters 'ba'ft been inscribed. .Above the :lJJdicator 

board and to the left are seen the :peiritJeriea at :tour mtaJ. noicma. wheels, at the 

"' left a svitch button vhich can be set to "encipber", ''aeciJ;ller" or "DeU\a.l." :positions. 

, 

At the npt 1D Fig. l (labeled II), the top cover plate bas been rmmvea., ezposizlg 

. tbe 1l1terDal ci]:IJerizlg mechazdam. !l:lree rotors or cmmection cbmgera "in cascade" 

can be seen attacbed to DOtchednU!gs. The rotors -· ••*•*?a nnf serve to cl:llmge 

the c1rcu1ts between the kaJ11 at the keJ'boa'rd to tbe lamps of tlJe 1Dcli.cator board. 

ID suah a ntor there is a circle or 26 equa.1.lJ'-apaced contacts on the lef't :tac•ana. 

a s1m1Jar circle of contacts OJl the ftgllt; face; vires passizlg through to rotor cmmect 

the cODtacts on the two faces, two b7 two, and these "Cmmect1cma an a:rb1 tra.ril.7 :mac1e. 

The rotors ha.ft engraved or paillted on their 1191"i:piberies the 26 letters of the 

alliJa,bet vbich letters elm be seen through ma.U W1Ddava in the cover plate, BO tba.t 

the rotors can be aJ 1gned. to the 1Dit1al. lmJ' settinl. At tbe lef't at the first rotor 

. ~ ~~ta.r 

is a~·-~, on the paripbeZ'J' of which are al.so 26 letters of the a:t.ipbabet. This~·· ba 

al.BO bas a circJ.e Of 26 eqml.lr-spaced contacts 1 lmt /these are ODl7 Oil its r1Pt :race 

llDcl the contacts a.re cmmected b7 vlres to 26 aoubl.e-pole, aouble-tbrov svitches 

. oiarated bJ llDcl associated vltb the 26 'D7&f of the kaJboa.ri.• The cozmect1ona 

dA.~ 'between tbe 26 contacts on the t'Mlt.• and the 26 nitcbes at the keJ'boa'rd are fixed. 

Blzt the 

~ ~tmW!r ~ i• rotatable llDC1 its position at &IV' time can also be seen tbrougb a 

V1nc1av1 labeled 3 in Fig. l (I), BO tllat the 1Dit1al aettizlg of the ".__._and ~ the 

tllree rotors can be seen through the tour v1DC1awB. 'l'be 1Ditial settizlgs Of these 

four elements constitute the kq li.'lfor the startizlg p:>int in ci:pbar:Lng operations. 

I used the expression "in cascade" a :mm1m1t ago, in refemting to the ::botors, vbich 
REF ID:A62832 

a~ •ans that tbe current illitiated 'bJ' ae:presa1l:Jg a lmJ" ot the lreJbom'd p.saea 

through the stator and then through all three :rotors before reacb1 ng a lamp ot the 

1ndicator board. In the ERIGMA., when the current eld.ta trcm the ~that 

~ is, the 

~ last rotor at the rig]:EtJ --~-· enters 1nto amtber stator also having a circle ot 

26 contacts; bUt these are cml.7 ita left face. Tbia stator :lfl.:fixed,o.- mm-rotatab1e, 

and ita contacts are cmmected,two 'bJ' two,'bJ' 13 1Dternal virea. 'rh:l.a stator, 

.-

&l ,, 

called a reflector, serves to :l:eturD the current, vllioh ex::Lta from mie ot the 26 

contacts on the riaht face ot the tb:ird rotor, back ~ cmrot tl:la 'jf. :Ota on 

N 

the right face ot that rotor, thence back tbroughAccmtact on the left face of that 

'/IAAJ~~"IL~~ rotor into a contact on the rigbt face ot the second or miMleAsns a' t>n ••*••» eta , 

~ to a contact on the right face ot f-Je left-baDcl stator. ~1rcu1 'tl7 in this -.chiDe 

insures that it Airl'c, tor exam;ple, then ~, in the aama position ot the rotors, 

that ia, the cipr :process ia reciprocal in nature. 'l'be circui tl7 can bef &ee11 in 

tltlil 

Fig. 32. It also bu,._a consequence that llo letter can enci:pbar itself that ia, .1.;p, 

. tor ex•nl\')e)can mftl" be represented~ Ac1 no •tter what poaitioD.ot the three 

c'--. 

rotcma llDd tlla left-band stator ha.ppm.a to be. The sane ia true ot all the other 25 

letters ot the alpbabet. The three rotors are interchallgeable, so that 3lc2xJ. or six 

pmmta.tive arrugemmta ot these rotors ia the •rhnm poss1b1e, since 1D this construct 

the rotors cazmot be inserted 1D 1111 "'Q&ide-dalm.11 position. In other tnes of sUQh 

mecb1nea the rotors are .ae ao that' tbq can be 1Daerted iD either a "r1ghtaiae~" J..c. · 

,,,,,... ~ 

or,_:'u;paiae-acm" position. 'l'hia ma.tea possible a wx1mn ot 6:xJl.x2 or 48 pt1"11111tationa 

ot tbe three ~ rotors. Of comoae, 1t 'L • a :more than three rcmors are 

availableJfrom which a selection ot three can be mcle,tbe pasaibilitiea increase very 

considarabJ.7. !l!he stator at the left can be DX>ved cmq 'bJ' hand; the reflector at the 

right is fixed 1D this model ot the :mmMA.. Depresa1l:Jg a keJ' ot the laQ'ooa:rd 

cause a the first rotor to a.dnzJce 

-"'L.t'-

one step, thus chlmgi!Js the ~ 

---------
--- - -------------------

REF ID:A62832 

circu:l t tram the left-hand stator, thence through the :rotors to the ref'lector, thlmce 

back through the rotors to the laft-hancl stator t:bus causing a second ae]ill'ession 

of the sama 1rq to procluae a ditterent eqm:valent. I won't talra the tim to tell 

. 

JOU about how the rotors are caused to advaDce ao that 1••~ ~·'·"° lf tll8uaai ietters can 

be enci:pbared before the w1DckJlr settings ot stator and :rotors returD to tbeir 1n1t1al 

a11guueut. I!- total mmiber is mt 1D this cue 263 or l~T6 but J.6,goo (2&£25226) 

tor tec!mical reasons which there ian't tim to ezpla:lDJ Power for the electrical 

c1rcu:l.ts is provided b1' aaall dZ7 cells 1D the 'boz at tbe UP,Pe1" r1Pt in l'ig. 31 (II). 

The or1g1Dal. mIGMA 8DJOJ8d a ta:l.1" cleg:ree ot success 1D sales but it vu 'bJ' no 

mans spectam11 •r. When Bi tl.m' c... 1Dto PJft1", fmatber sales were prohibited. 

'ml 

Suttice it to sa:y tlBt it bec.,+fe tbe basis tor machines used b.r the German Armel 

Porcea 1D World War II. 

;. ~'Cito, rrwlw 

In the u. s.~a C&litornia 1lmmtor mme.i/ Bebern 1Dda1*-~ conceiftd a machille 

~~~...t;~fa.l.id., C! ~CMeu.l 

-.ch Ila call84 111 "elec1;r1c cacle" • A it r a:lm:llBr to tile IBilllA but with .._ :llqcrtaat {· 

differences: tlJe ciitm' alpbabeta proaut:ed 'bJ' 1t were not reciprocal mut, :moreover, a l 

pla1 n-text letter could repreaent i tselt 1D tbe ci:pber text. Jle'berD wnaged to avoid these~ 

two weaknesses 'bJ' 1.Dcorp>rating a Ritch plate which could be set one 'Wa7 tor 

encipbering and aeci:pbering another Wiil'. OD the otlJer hand, not as is the case ot the 

It· -+-L ERIOMA., the e~trical c~s mae cml1' one trave/se through .the .. ..,-:"''la~ than 

j;u..,e ... l1:~~wfiw.,,_.O"M&.~ ... oJ...~~~"1W~~ AOY~ two,,. e encipberment the curre.nt wen.t in. one direction through the :rotms and 1D \ 

~ICa.~~-

-i:pllenmlt :l.D "tllll rawrae cUnctiaD.,. lllre 1a a alille (Fig. 33) -.ch.-.. llabam'a ~ 

Vfn!7' first model, 1dd.ch lJe constructed tor ccnmm1cat10DS ot the IU IO.we Kl.Im. You 

vill note that this :mocJel has but one rotor; also, tbe cipber machine is cmmected to 

~ 

an electric tJ'.P9V1'1-ter so. that hand recording ot results was no longer neces11&1'7. Om ~ 

:z::. 

m aclditiOnal T:lrtm of the Jlebem D8Cb1 ne vas that the wirings in tlle rotor were Tariable, ~ 

.._z.. 

a feature not 1Dco1"porated in tlle :mIGMA. rotors. Bebern interested our R&V7 1D l:l:la l" 

- '3J'\ -
REF ID:A62832 

:machine and built the 5-rotor moc!el which JOU aee 1D this Blide (Fig. 311-). Tlle rotors 

,-

&1"e ilrterc:hmlgeable and can be 1Dserted '!rightside-up'' or ~1c1e-~11 ; ~ 1DterDaJ. 

' 

YiriJJS could be reac11~ clumged. But this va8 mt a pi.DtiJJg mach:lne. Power was 

~L ... t4Al'd•--~-fir'JCwo6u..L~~ """~.\..;~ turnialJed 'b7 the amall clrJcell seen at tlle up;per left. The B~ was c:cmsia&riJJg 

~ ~2.tu... pirc:baaiJJg a rather~ mnber ot i••a mddre1 •i Lielh.stru'.bel, the Chief of tha 

Ra.V7's Code and S1gnaJ. Section of the Ottice ot Raval (!onmm1cat1oDs 1 asked me to 

stuq the machine tor its c:rntosecurit7. 1'&'9J' had 'but two machines, nei~r ot vld.ch 

~~~.~~ 

could be -.de available 1 ao I :lnd»aed tl:le Chief/ 81 gnaJ. Officer to b1Q' a couple ot t!lemA 

woA'f.oaA-0-"' ~ IC\7.4'-. of,~~ tor -,. 'l'he rotor v1riJJgs"'ware altogether ditterent tram those ot the Ba'VJ', a tact vl:lich 

I discovered s1.mpl.J' b7 a.aJr1ng stmbel to emipn/f a tev letters OD bis mc:Jd.ne, usiJJg 

settiJJgs I specified. After m stwv I reported that 1D IQ' opiDiOD the securi t7 ot the 

macb1ne was :aat as great as B&'VJ' thougbt. T.be result was a c'hall.enge, which I accepted. 

Ba'VJ' save me 1;eD messages pzt up OD its nwcb1ne and I was succaaafal 1D solving tham. 

Dare tan 't tim to go 1Dto the mthods used, but it JOU &1"e 1D~sted JOU can f1ncl 

them cJeacribed 1D IQ' brochure mtitled ___________________ • 

lfeber.D built sevwal :mre model.a tor 1'&'9J' and these had :printiJJS mecbaniams as110C1ated 

with them, but Ba'VJ' dropped negotiatiODa with &tbern when it becmaa obvious that he 

was :aat ccapetent to build vhat 1'av7 wanted and needed. lfa.VJ" then established its own 

crntographic research &Del developaant UD1t at what is mw kDovD as 1il:le Ba.val Weapms 

Plant in Waahington. .Artq developed at the 81gnaJ Corpe laboratories at Fort MamlllJuth 

' 

a macb;t ne kDom as Converter M-134, and /bare 1 8 a slide ens. 35) sbav1ng what it 

looked lilra. Ar., and Ba.VJ' vent aepa:rate 1fB7B 1D such 'llOl"k tor a mmber ot J8&?'• but 

I 

I 

ti~ 1 1D 1938 or 1939, close collaborating 'b:rougtrt as a reaul.t an emellent :macb1 ne 

! 

~ was develoJled and p-ocluced 1D ~1t7'b7 the 'lttietne Corp>ratioD 1D Chicag0. 

I 

- ! 

This macla1 ne was diatr1¥8d and used 'ft1"J' aucceasful.17 b7 all our .Armd :roraea tram I 

I 194<> to the end of World; Wa:r II &Del for acme 19a:ra tberea.f'ter. This was a rather 

-3o-