REF ID:A65316 

., 

Intrg,dugtian 

Be.fore I treat the main topic of rq lecture torlq, let me delve 

briefly' into the history or cryptanalysis, and we Will begin with a 

cursor1 backsround of oryptanal..vsis in ~orld ~ar I and the subsequent 

poet-war years. 

Qommunication lntal11ienga in ~orld ~gr I 

'11hen we entored tho war the United States had at the time no formal 

cryptolo,;ic or<?aniza.tion. The British, the French, the Austrians and 

othera had cryptanalytic or'J&nizationa which had been functioning for 

' quite soma time. In order to protect the source ot intelligence, the 

Britiah at first shrewdly attributed their own unc$%11>7 succeas in locat1ns 

enall)" torcea and rrod:oting enemy movements to the err1c1ancy of their 

direction finders. It has since become known, however, that cipher expert1 ol the famous British Room 40 were to a large extent reaponaible 

for such import:int militar.v and political events as the !3att.J.&a o£ ..rut.Land 

and Falkland Islands, and the detection of Zim.~ermann•a attempt to 

obtain the support or llexico, which P~•d an important role in 'stirring 

@'pproved for Release by NSA on 04-30-2014 pursuantto E.O. 1352a 
REF ID:A65316 

J 

up publlo opinion 1n the v. s. against G•rmarlJ'. The Earl of Halifax 

evaluated the work or this group as toll.owe: 

••To Room 40, the country owes an immense debt of gratitude - a 

debt which nt the tims, at least, could never be paid. Secrecy waa ot 

the very essence of the work, and never waa eearecy more auoceaetull.T 

observed. 0 

Similar successes were achieved by the fre:ich on tbe 'Jestern Front. 

The7 rttpeated.Ly broke the German ciphers and obtained inva.1.uable 1n.t'ormation aa to Ge;rman plans and intentions. Likewise the ~rmane and Austrians 

had great success with the Russian ciphera 1n 'Xorld War I and undoubtedl7 

aucoeecled in brin.Jing tho vnr on the Eastern Front to an ear lier close 

because ot this fact. As for American com~unic~tion 1ntelli=1ftnce operations, 

the succeasea achieved in this count1'7 prior to Woild nar II were not of 

auf'ticient importance to impreaa more than a handful or ofticera with th• 

~reat potential value or the work. 

Collllll1lnicat1op Intelligence bet.,an 7.ara 

Al 1ntereat1~ as the revelt\t1ona ot -·orld ;;ar I proved to be, their 

real si~nificance lq 1n the profound erreat they had upon ~-io , ... v. Plll•nta 

2 
f 

,• 

1 

ti 

• f 

t ,, 

:, 

l, 

w__ -

,• 

1. 

I' 

REF ID:A65316 . 

' I - :1 ~ ,I 

.aecm"1~ conacioue. The Japanese 1n part.1oular, who •re pr~cnmdlJ 

-. - ehooked at the rnelat!ona or the 1rre1poneible tardle7, e11barked upoa 

a pl'ograa ot formidable aopb1et1cat1on ,ot her c?'JPtopaph1c 8711\•• 11 t.o 

........... - I' • 

the ;nat. detriment ~ our nat.1oml int.e:resta 111 the 78aJ'a prior to 

loi-ld lai- II. Yardle7 bad been •pl07edi\ 

1I1-0~ b,y the St&te ~~ht~ DepartHut.A :t.n J~ .. ~ 

oomamn1cat1on intelligence activ1t1ea, and he published a •elodr&11at1o 

'book, "The !.lack Chamber• in which he wrote ot our aucceaa •1th 

Japanen codea durinc the Washington nanl diaanuent conteNnce in 

1921. The book created a een1ation in Japan &nd was wideq ciroulatad. 

The Japanese felt that tbe7 had been tricked, and wre extnaeq reaenttul. 

Untold _han ne cauaed br Yardle7pf •1olat1on ~ eeourity which he billaalt 

1A hi• previou ottic1al position bad ooanaele4 othaa never to reveal •, I 

'&IV'\hiar ot the work. A direct.and immedi&te effect. ot Yar4ley•a utort.unat. 

I - .. .. - ... I 

80\loa .. t.o require \la• •'1.91'01•• ot th• areat.eat caution aad 8801'907 la .... ,.. ._ .. ,.I .. "' ... I I 

~ I ... "" .. -. I 

~ ', I .. ;. "- .. ., I o, 

.. ~ J - \ ot :, ' 

' : I •'' • ~~ .. ~~~- • ~ : ~ , ·,: ~ ' ' ,•' • • • < " • ". ' > 

I 4. .. "' - I ofl f' .. I \ ._ o" "'"'c '"'t L 

,,.."1' ... - - ... ,1 ~- ... : ..... {'I -l ~ '\ ....! ... , .,..,... ..... .. \,. •"' 

.. , ' ('"" .6.. ... ,' , • :: ~ ... ~ 

0

1

U'Z'Jlng on c~ioation lntellipna• wort. ·,The reault ae that i\ .. _ ., ,., .. - -. I I .., '*' ... ~ ! I e o\-t "9. 

I , ... "' I,., 

~ .,. I .. I .. '" r-.. ' I I '"' "' " I ~ ., - 41\.A 11 "r.,1 :'. ,.. ,,..L I t1' I 

118ftl' PG••lble'to pre1eat properq the -.S. flt \he ooman1oatlon latellipao• I .... ,, I ,. •'":r " .. 

r '_, ..... 't ...... ill'~ ~ .. 

I'"" ...... /'.. 11 

V "' 'Ir I I "' .. ,.,, _.. I 

,..-. .. II. ' . 

~· ' -;:-'\' .... ~· 

I ' 

. ... ' 

' ,_ 

- I .... "'._• 1~ "', f.. .. ,, .. .) I "" '\\'~"' f' I I I r,1: • 

.... .,, ..... --.!~~.:..o&..-...:.....#==....::::. .......... - .. -L""'-~-- .. -- ... ~··---... .!.---!...JJ .. ,.. ----.Ji .. -~ .. -:_ --~'!!......-\,,,. .... ----
REF ID:A65316 

-- •r!c.nization L'ld to obtain tor it the auppol't ne~••S&l7 for it• eucc•••· 

The no17 of what was acco11pl 1.shad •1ncl81' t'i••• dUtS.aultitJ• pri.01" t.o 

.tearl iiarbor ha• bee"l a'> \\idely publioiaed thll.t. 1.t needa no reiteration. 

~et it 1Uft1oe to S&.!" ~hat it took ~pproxilll~~ely •13hteen ~o~tha ot 

pa1nstak1Dg labor to reco:a1t!'Uct, t.._rough cryptanal711a, the coaplex 

machine ttat - uaed b7 the Japanese to enoipher their h1Jh•lt•lavel 

diplamatio c01111m.nicat1ons. 

Ca"?!gicat101! Iptellift'°' ip ~or]d !K II 

T>1e importance of comnu.'1lcat1oa. 1rrtell1gance in :'.orld Star Il is 

pro'babq best 8UllllU'ized by the following statuont wb lob appears in the 

fiaport. of the i- aar.L itarbcr .investigating Connittae or the 79\h Co1111'••s1 

"ill wit.ne1see familiar with comun!e!ltion illtellipnce "sterial 

' throu~:hout tl'e war hava te£t1fied that it contributed anorD'ouaq to the 

defeat ot the emnt7, greatly sburteneci the ,.sr, and sand ma,,,. thou11alld1 

of 11vea.• 

When the United. State• entered tlie war, lt had made a tillid beginning 

in the fielc! of commun1cat.1on intelligence 4ue to laak o1' t'unda, personnel 

4 
REF ID:A65316 

and equ1Fment. Jn certain phasaa of the ..vork, notabq the aolutiou ot 

the Jor~~ne1e d! plO""st1c "'!.chine, brilliant eucceases bad bean aco'Nd. 

fhtt in co~~~rison with the situ,t1o~ ~t the so.r's end, exploitation ot 

from f,~6 .f:>int o! intercept to the CZ'".f"t-itanalytic center were hit or miaa1 

crypta'1al.7eia bud baan cnrried on sucaesstall.y o'l.17 in carta1~ '16rrow 

f .iolds, and -- at least in the flay -· aethods of gatt1:'.JI 1?:ttelli;enoe 

troui tho tl'ati'1c short of raad1£18 it wre u'litmtlopadJ there \18.a a cr1t1aal 

ehortage ot trar11;1atora1 there were ~either sutt'1.oient persounol nor 

aclequate proceclu..-es i or atudyin~ and obecking the tru.nslatad product to 

aquae~e out of it all uaetul intelll~encP ~~t~1nable; the method of 

presertltlc: tho .:..srived iate ... li~nae to the roapa'lSt~J.o uut.h:.r1t1ec ln 

~'aahin..,="ton 11rao ineffective; ane there was no arratJ:J•ine~t fer .;ettinJ such 

inteUiJonce tc comr.J&"ldera in the i"lelJ t1ramptq and ln a ma!l1'l81' tihioh 

5 
I REF ID:A65316 

'1!ot:l.G protect. the sO".irco a"ld insure securit,-. 

a~eamont, ros::onaibilit7 !:or the interception, 11nc.l7s1s, solatio~ and 

rr.1.11Uir7 traffic • :.:rev; navaJ. traffic - '!1197; diplo"":at1c tr:d"fic .. ~my 

and Na,,,.J c.Landesti:le tr3fi"ic - Coast :>uard. Other 3oftl'nment S.fIB1lC1ea •:re 

alao takinz an i~tereat in the field, i=ic.b1di~ the i:·~I, t'1e FCC o.ncl the 

' 

predacas&cr of ~"ie :cs. In the :real"':: ti> co·1·111, t~e!'e '1as to be ritns:saed 

a tantaeti.c growth l-'1 or::;anizatio:i of the laJ"1117'a and Jav.Y'a cr)Ptolo~ic 

or;ro.nization.a, sr..d their combined ei"!'ortr; ~ rorincod ~"" #1.niou~t of h13hkmtw the sizs and 11.~itntion~ ot tho pre•wlJl' or~an1z~tione. 

Th• !iattles or r'i.iwa.J' and Coral :A& ?.Ore oftlv two or a multitude ot 

examples of crnt.analytio teats ot arcs, 11· I D'.SY" be per.l!littad to mix a 

metaphor. According to tbe official nnrrative of the Combat lntelliJonoe 

Cant.er, raa1t1o \.caan t.raa1, 
I 

REF ID:A65316 

11th• taoiora t.1uLt vital.q affected the aattJ.e ot iw_,. wre 111&1'.\V 

aad CO!i"plex, but 1t is uuaouotecily true t.hat 'flithuut :radio 11~ll1...)eno• it 

souJ.d have been 1mpoaa1Dle to h~v9 achievaci the aonoe~ltration af rorcea and 

the tacticcil surpriae that macla the viotOl'J' poaalble. •• • In tr,a detena1ve 

staJea ot the ar, ra.clio intelJ.i~e:iae •a• not only t.he most important 

source ot 1ntolJ.13e'1Ce in the Ce?atra.1 1-a.oitlc -- it was practiaally the 

onl.7 eource. "Zb.ere were very few capt11reci d.ocuamenta or 1lr1soners or wr.ar. 

There wore no photo31"a.phs ot eBe117-hold pocit1o48. I:. the \ientral .1: acli'ic, 

emluc..:ln3 the C.olalllons alJ(] .le• ilritaia, spies .ancl OO!i&ta"t vatahera 1 repeirta 

?left!" supplieu an.r im?ortant 1nt9lli::enc•·" 

Other 1:nportant nam'°'lea o£ the uuacesaea ot crn.tanaly1ia mq be 

clted.1 

l. lhe movement o£ fov.r Jspaneae di'lia1ons into Ja:rma in the 

prep3l"c.t1on tor the drive into Ind1at which b•gan in ,;arch 19'4, was 

diacovered iar in advano• ot the beginnin~ ot that attack a."'ld a m:mb_. ot 

indications that GD attack wa1 pe!ldin.l WN obtalned. 

7 
-

I REF ID:A65316 

• 

.. 

2. The Jap.a..11eae pl.3..""l .tor S.;4 at.tack en tbs Torokina perim1:1t.er in 

"'. C. a.tt3Ck ns cilscovered. 

4. 'Ille c:o!la>lete Japa!lese ?hn £or a11 at'ttlck O!I the .1..1tape 

moved i:lto t!1e area. Olld that it n~ dofe'ldc"t o:oly 1)7 ncr~ice tro~a. 

a 
)' . .... 

I 

' I 

I 

I ·' ' 

. . 

I 

\ 

' 

~ . 

. .. ,

~~ I \\ 

\ \\ 

-· 

-, REF ID:A65316 

comunioat.1011 rea41.Dc i:i part u tollowa1 

"th• Commacder:ia Chiet oft.he Comblned fleet, Adlliral I1oroka 

!uaaoto, dled an heroia death in April ot thia 7ea in a1r amabat •ith 

-· the ene117 while d1rectl131 operations from a tOl'llard poaltlon.• 

The Japaael8 DIY81' tOU:Jd oat until the .t'url Harbor lDYeatigation aat 

it aa that actua~ killed IU1U1oto ·- inadequate 01'7P'top&pq. 

\ n . ' \l d\ 

I \ \,, 

!. '• \. ~,.·i I 

. ' 

\ ' ' ~. :1 .. ·, ~ '\ 

• 

';. 

' 

~ 

I I 9 \ < • 

L 

,, 

.. 

,5.. 

______ , ___ ... 

.--

,,..,..· --

... .. :!1 .