.. -

• ARMY SECURITY AGENCY 

WASHINGTON &8 D C 

!7 Aut' .mly cl ti:. 

Cce1c.ar.!1a41 Guiiitci:l 

w~ +~- ------~--------·-~-~ 

WDGSS~l~ 4 December 1945 

SUBJECr1 Historical Report 

TO 1 , Deputy Chief• MIS 

Room 2E 800, The Pentagon 

Wa.shington 25, D. c. 

In accordance with your telephonic reC!ueat, herewith is a copy 

ot a document entitled "Prelll!linary HistorJ.Oa.l Report on the Solution 

ot the 'B' ?ta.chine," prepared by me on 14 October 1940, shortly e.f'-l;:er 

the ''Purple" systen was solved. 

l Incl 

Pre Hist Rpt on the 

Solution or the nB'' 

Machine 

1»~~~~ ..... ~ WILLIA&'! F. P!tIEDMAU 

.Director of Comnn1n+cat1ona Research 

' • 

Declassified and approved for release by NSA on 09-05-2013 pursuantto E .0. 1352a 

/ 

& 
PR~LI~INARY HISTORICAL REPORT 

Oii THE 

S 0 L U T I 0 N 0 F T H E 11B11 

I I 

,. 

V!illiam F. Friedman 1 

Princi!Jal Cr"ptan-alys t. 

October L'+, 1940. 

StCRET 

L 

r~ -
. 

< 

II 

. I 

i 

, 

I 

I 

1:ACHINE 

Part I. Technical 

.. I • 

1. In the latter part of 1938, messages &f.peared in a spec1al 

secret Japanese ciphar giving the author~zat~~n for travel for a 11Commil."licat:.ons ~xpert" named u~"D.oto, in order that he might put into service certain er- ;.tografhic pa.ra.;Jhenalia' ter:ned b1 the Japanese diploraatic 

offices as the T"JPe "B" cipher macnine. This machine was to replace the 

then currently used Type 1rA11 macnin-e for highly secret com.nu."'lications 

a~ong the i.~Jortant Japanese embassiesl throughout the world and the Foreign Off:t,ce in Tokyo. On l~ebruary 19, 1939, a message bearing the date of 

origin as Febn.a.ry lE, 1939, in superenciphered coda (K-1· tra."l.sposed and 

enciphered by special A-.uachine procedure} ~1as 'lll~rcepted and was found 

to give the effective aate of the initiation of the B-:r.achine~as February 

20» 1939. The:A-machine was still to be used by all holders for certain 

classes of com::iu.~ication. 

2. Among the first messages received a:fter the effect!.ve da'te or 

the B-machine were three messaies,originat:i.ng in ~arsaw,,mich had a new 

t:rpe of" 1rJ.h.catcr instead ot the norm.al 11A'1 type indieator. "Eu1in:t!.on 

or these messa:;es sho.t"ed that they V:ere definitely not 11>.11 t:,?e messa5es, 

but due to the fact that six or the twenty-six lett9rs appearing in the 

text 0£ the m.essa~es .,.,ere abnor:nally high (as the:r NOuld have been had the 

A-machine been used for their enci;herment) it \'ra.S assumed that the messages were p-:r;:epared by the B-machine and that it """B.s c1. 'llOdJ..i'i.cation of the 

basi'C A-:nachl.ne. Further int'3rcepts tended to corroborate tl-is theory. 

'"~: ·--'"c'--,.,,e •;as ccl"'t1nuad in reg-J.lar use -at P.s!.nkinci and Shanzhai and 

very occasionally (a.pparentlI" vhen w1e .::-·:-&ilc •• ::.na , ~.3 c,_ ~ o~ ~:--:.. ~i<:-::. ..... ' 

t"ie A-nacr.:.ns continued. to be e:nployed at the ;ilaces i,mich had been prcvidea "Ai. tu ~-:nachJ.nes. 

:;. After a brier study it ""B.s,,.confirmed that the ciJ::n.sion of the 

l:etters into t\iO categories (one group of su: letters and another. group or 

twenty letters) which was the basis or the cryptogra.,")hic treatment-in the 

A-2&.c!u.na -,.as retained in the B-machine but Vil.th a very 1.ID.portant chan3e. 

iibereas in tne A-machine the 6 letters comprisUl5 the "6's" as well as the 

20 comprising the "201 s 11 ware enciphered by means or what had been deducea 

as bei..'lg a rot:Gtin~ com:nutp.tor, -whose stepping ;was controlled by a break 

1.·t-.eal or 47 positions -wrth 'Certain skips in the cycle (the ,Cp'11&1l.Ut..ator could 

advance· li 2 or 3 ste..;>s at a time), in the B-:nacni.ne the "6's" were en- c~p}i~red·by mians of a series or 2; heter~eneous and differently mixed 

alp~a~~ts which ~ere c-0nsta.nt in their nature and cyclic repetition. These 

25 al.l:' ... habetl:» l.ere merely a carefully s.electea se.t of 25 of the possible 

£20 p.e.rm~~r1o~s or transpositions of _6 elements taken 6 at a time, and a 

--.------.; .. \ f6?' ~fg~ff 1 ':"asbin~1fr.\~erlin, London,~Pal'is, t.::oscow, Ro:ne, Geneva, Brussels, 

Ankara, &f, .an~~r1ai, and Peking. 

f . 

" 
«< e. 

1 

--

REF ID:A6784 

~~ deciphering chart or "developc.ent' Yras c nstructed to corres.t'ond "l\"l. th these 

25 pernut.a.tJons. This chart Nas revised and correc~cd fror.i day to day 

until it bec&~e certaJ..n that all its elements were absolutely correct. 

4 •. '!hi& hav-.i.ng baen accoIC.plished (by April 10, 1939), it teca.11e 

possible, ts a res~lt of crypta.~alytic techni~ue elaboratdd fer the purpose, 

to deci&?her the "6'.s" in practically every :nessaee o! &"'lY consider.sble 

length in the B-cic:..c-hi.ne. It \\as found that so far &s the "61 s" ~ett;een 

two messages .nth unlike indicators l-ere concerned, the cnly difference 

'bet.- een cne indicator and another -.,as tlle stuting feint in t,he cycle o! 

2S al;:habets. T!.er.e were 120 oifferent indicatcrs- but only 25 different 

stcrting poi.~ts, so that four (tn cert.:.in cases, five) d~fferent indicators 

r.e?resented the SEQe starting poir.t. 

s. ·ihen the 11 61 s" in a given messace 1 ere decir;rered, the plain te:<t 

valu~s of ciphdr letters scattereQ here and there tl'..rc\lGhcut the text beca=i.e 

av&ilable, so tt.at the skeletons of rords and phrases offerea the:c.selves 

for completion by the in;:enui ty and t!'.e :L":tae;in.ltion c-r the cr:~tanalyst. 

For ex&..tple, sup_pcse that on a ~i.ven day the 6 letters fon1ing the 11 61 s" 

were E f.,: A D R H and the follo."'1.n6 te~tt \\as at hend: 

Cipher: a~AX~FQCEV~OOXHhCFDLNqtaV~PPLC~RP. 

Pl.a.in: H E A A E E E R E ,. P. 3 ~ E P. J. • - - - - - --- -- -- - ---- - It is not dif'f~cult to imagine.. thait the mx-ssing_, 1.etters are ttiose 

sho .. n below: 

Cipher: 

Plain: 

B it. A X E F' ~ C E V ~ 0 0 X H ~ C F D L N H ~ ?..' V :;, ? P L C .: P. ? • 

T H E J A P A N E 5 E. G .,,0 V E ?. N .1o• E~ 1~ T R ~ ·: l:' E 5 T 3 T tr J. T - - - - - -Ji.- - -\- - -- - - - - - In this process of' tilling Ln the pla:-n,.text values of the 11 20' s" t.'li.e 

cr,11:>ta."1.alyst could be ~ic.ed ~:mly by t\.o t~.in3s: (1) tne FOsiti.cns sna i:..e -

tities or the deciphered "o's" and(:::) the cc.ntext. ror it sp~en.l;r, :::dca...,~ 

apparent that any cryptogra~hic relationship betNeen the pla.tn text and tl"'e 

. . 

• • 

• • 

' constantly-shifting cipher text values in the case or the letters co~stituting the group of "201 s" had been mbst carefully eHminat.cd, disguised, or 

suppressed. This fact corroborated tte conclusion drawn fro~ all stetistical 

and a.~alytical tests made on the cipher texts of the various ~essages studied. 

6. The process ·or filling in the plaJ.n text valu~s or the "2C' s 11 Twas 

therero~e,as a rule, a very diificult ~tter, deoend~g usually upon the particub.r assortment or letters constituting the 11 6' s". If the te·ct •.as in 

Je-::anese- there was, in aclditi-o" to t.~e difficult~· inherent in that lan'.:".Jas_e 

itsel.f, the added perturbation occasioned by the fact tha~ the Japane~e Foreign uffice t:.ad 1 en :.:a!r, 1, l9J9, instituted a S?ec~es of "rh::!..llips Cede :n 

co"l!'lection Ti. th thair use of the B-.""ta.Chl..ne, -n. th a Ieng series cf a.r?n. tr.?::.'1" 

letters and abbrev~ations st.anding for nu.~berb, p'lcIJctuciticn si:;ns, ar.c freG.U.entl;r used co111'Qinat1ons or letters, syllables, .;c:-ds, ana. sor.iet~es co•-

:,lete phrases. For instance, the com.bi.nation C F C r.epr.esents p~r1..ou; C C F 

represents para&raph; the sinGle letter L (not normallJr used in Ja~a.~ase) 
SECfU: I 

re~resen.ts the di:.-hthong ai; X represents ei; P represents m:,; v :::-epresents long U; ~ 'l" C.. represents J.rJ.ta (s:n.)_ili,p'1l. tashi; E Kt" rei:;resents 

BeikoJ..-u (• United o:.tates); 'i' iI l, represents Tei.kok\..seUu (• J;.p.snese Ccverrunent); S r: \' represents Su~{unakarazu, etc., etc. ~ne difficulties introauced by tt.1.s at:breviated or rat.1--::r codP 1;r1t,_ne alone m~re ;1,i:e sta--

E.ering as well e.s ae;grav!:.t~nz;, for o!ten the "text" even ,1hen finally re: 

constructed appeared more 11ke code or a ra11dc!l assortment. or letters tt·a.., 

plam text. 2 For the recc•nstruction or such text, the seri.ices or the 

Jaz.ranese ex:Jerts were absolutely essi?ntial, and the ~-ork 7;ent ver:· slo· ~Y 

not or.ly because or its aifficul ty, but. also because t.lie services of ~' ese 

t.rdllsldtcrc: were available only a S!"lall part of the time 11.en tl:-e tra:.r::c 

r_cr the daily 11Bulletin11 pe:rinittcd, iii.~J.Ch 111as quite seldom. rto .. e·1t::r, occ:as10"1ally 1t Vlas .f'c..u.11.d, after the 11 61 s'' in a eivcn C"essa.:e had teen dec ... ,.hered, tl-:::.t the.:;e letters and their cb.stributic:.n t..'lr1 Utit.out tl·e .nes::.ai:e 

~ave eood ind1cat1ons of the _;iresence, J.n •:hole or .:.n part. l.fl •the J'leS!:C: ·e 1 

ot nor..1.al jngli.sh text. In such cases,. the 11 ~35S::i.~n process :'s lil·elj· 

to be ccnsiaerably ea&ier because cf the aosence cf abbreviations (except 

f(lr :;.unctuation signs, in \,·tiich case tbese were a help),because of the ... 

2 A typical exa111ple of the sort of 11 text" usually found at the beginn!.n: o! 

mesS2f:eS is the follo\'11ng: 

Ci&= her: FGFXP 

X F CG J 

IXUDB DGECZ LB"LHU Z~O"'"H 

'1•FOVD DNOBB FYXFO CFYLC 

YNA-?.': 

Plain: CF - S G 

DE IL 0 

t.nit'I 

A X. P p p 

C G u .i. V 

Z?GRA 

W '£ L S I . . . !~e rortert eroupine of letters and the i~+erprotP.iion ~r the fore~c~~: 11 phin text11 is .as .f.ollows: 

1 F C = Da1 - gCS 

GJ1':=15 

F 0 V = Open parenthes1s 

DD =2 ~~ C, • "cf11 (Jap.plain text 

a a • l 

particle possessive) 

i! s = 3 

G T 5 = l'Jetsu (month) 

J V R K : J'iiroku (= 16th) 

H I = Japanese -;,ord for ''da .. •

11 

F I C = Beg"l.11 kana spell1n~ 

~ U !'! V = CurU (= Gre·;) 

~· Y I = Close parentl:.esis) 

F G C = Cokuhi (= ~ecret) 

F E L = Close kana sncllin~ 

B K "; = 3e1koku (= u·. S.) 

T L 5 I = ~aishi (= Ar.i.oassa~c~) 

F Y L = :.~ancho .furze a tuka1 

C C F : Sni.n s~o (= Paragra~h) 

~-:i .runnin~ la.nr,.~ze, the message be~ins as fcllo11s: 11!:u.-nbe:c 15 (pa:-t 

" puts). ~ecret, to be kept .-11th1n the Depar'buent paraGr&.:t-h Cn ... arcn 

the n.n::rican A:mbassador, GreY111 , etc. 

- 3 -

l c! 

. , ._ .. --... 

I ~ ".,.. 

,.. .. " .. - T.:; J '"-,. 
' < 

er nt.a-"UilJst..' s :rea te.r !'2~ 1ij iu-.i t:r ~r!.. th fre lan':,Ud~e, a.ri:i °!:lec~ue~ o!" tnc> 

ava~lability o! 7.h9 serv:Lces o! a lGr:er n~Taber of nvr~ars. It h.s.~~E:.~ed 

.. '"~t "•n cavaral cases, after a fe•· ~'Ords had tl-.us been obta:.rsd b·• ;.r..:. '-•"' .. - -.. -- n -,,.essi :l:::;" J :;.. clue • 2.S affcrt.ed .;.:; ";.c t.""1e ~9ner"ll :ut~•.ire- Of t- •,e ~e:::scr:;e 

a;:i t~is lod to a ...fr=-..utic saarch ~or &. cc:!!.plete aocu:•1ant • hic1l ·~.L,znt be 

aval.lable ei t}Ler i.."l our ona fJ les oz l.n t .... e f~ las c.:t ctr.er ;;o·.rsr"lrtt:n t. 

:.-~~c es.~ t.na case lrd's found in •"' ich the B-r.iacr•u1e :nessa""e ccPta_nad a ~-· ~ 

,.. t 

1../! ........ 1 \L •• 

;.a:-a:.h:"a.sed version cf a ile:;sa.£e uhich he:.d oean trc-nsi'".:i.tted in .-1 cc ... ~9. 

;..c.·:;.;.ta:;e :as, of' ccllrse, l.Ii'Jnediat.ely taken of tr.is circu:nsU:.rrce ::l\..t t'1e 

e~~:.re te~t er tne B-~achl.lle T.e~sece coulo never oe reccnstructed fro~ ~·e 

pa:-a:J:l.I"a.sed ~-1. vars: on, possibly beca..i=e of the excellent. para_.~.ras .ng, 

~ossioly because or the ~resence of abbreviations, possibly because of be~\ • 

C-=rtai~ :..n:;li ~!1 tsxt "llessa;es, no•"ever, uere recc."lst:n..etaa,, scme ?f ttae.n tc 

t:IG e~te~t cf ~0-95.v, because the aoct..usnts being quot~d in ~h~ nessa:es 

wer-.:: :ort.mc:.tely :locat,t=d and ottai.ned,, most often t.'1rou3h tl.e cco..:>era'l.1on 

~nd ~ood offices ~ G-2. 

7. In all, the plain tex.1.s for parts o.r SC"'id 15 i"a:irl,.v lengthy 

.:iesta ... es ;-ere o 1ta. ined by the .ne thods indicated above, and these ;•ere -su'JJec ~d to most intensive a."'1d e>:l"~usti.ve CI""'"ptanalytic s.tudies. To the 

cc-:isterr.a tioa ot the cr!'";•tana.lysts, it u.:'!S found t•1at not onl7 y,as tt1-:?re 

a co 'i;lete and ab-solute absence of any CCLUS9.l ref.etitions .d tb.n a11y.' Si.n:ln 

:a~~sa,:e, no .:aatter how lon;, o.r bet?.een t"~ o •nessages •'Ii.th different inC.::.-

c;.. ....crs en tne sa.F.a da~,., but also tt>a t -d1en repetitions or t.hre~e, or occ~­

!1cn~ll:; !our,c1~b..er letters ~ fou.~d, these nqv~~ re;r~se~ted the sc:..,~ 

)laLn ~ext. In ~~c..1J s s~~ti~tical e~lculat1on ;av~ the 2st0r1sr.·n~ res• l~ 

,::.!1..-1. ti.e :iu:n.bar of' re:;et:i.t1cns actH::.lly ,,re-=ert .!.n these- cr•-to1TS.."1S • 2s 

• _.:; tc~-i t'1~ nu:n~er to be e-.-::;ected hao. t:·a letters C')rnpr:i.s:n::- t~ ~.:t .. .: ''"':. c:.t rar.do.ll out o! a hEltt A,>!Ja.rently, the m., cl·~ ne had •n t.~ nc1l:.c1nus 

:nr.. -- mt ":>r1lb .... ..,:.1~r -- ':j~ ::--i c-..,:~!'"-C t_ ... t.c ::.u.p;.irf=&S al:l: plain te:1.:.t 

1.c:,:1et.it.ion. :ievar'&heles.s, th.a cr:'Ptanalysts ru::d o. ~eeling that th:i;s. very· 

circurnstarice.-.7ould,_ in ::he f:in;!.l PnP~..,-::-:.s, t"'!'::.ve t!.. ~e :.:.e 1·.p Loin.:; o!' ~•: 

- .. _ ... a.::. a::r. Ji~C,lari:i.~.n. l.xla so 1 t turned outt 

a. !n all the foregoing studies; several factors stood cut'!. First, 

the basic la., undc::.rl,ying t.11e 3-'1la.cr..1ne 1'/a.s of such character that th~ 

ci~n~rin~ necc..arn.s:cs seemed to start from certain initial settLnt;S an~ to 

;rcirass absolutely ::i.etl1caically A!.thout_cyclic repetition of Rn·· sortastrai rit t!!!"CU.C"h to the end cf ~·1e nessa'""es, the lon,::.;est o:f ;·tich for ... ~11ch 

;;lai.:1 teY.t bad been reco1rered ccttt1 r:.sed over 1, 500 letters. Eeccr.dly, two 

!centic:al pl£.in-tez1., letters in sec;uence could never be·repr~sentad .. by t7.o 

ider.tical c~pher-text letters; nor could t~~ ident1c2l plain text letters 

:Co letters apart be i"1 er ti ca 11y enCJ..!-•1-ierc.c!. - T'1is p~enomenm wM c ... 1 vras 

ter.red ~·s~ppression of du.pl1cate enci:t--herments at tne lst. al"d 26tn 1.n •,arva1s'' .fc"r;.~e~ the Su!:JJ::ct of lo!le and arrlt...ouf> stuu:,•, .fr ... 1tla.:is e~ari..-entatl.o:.n ani CIJCn C.l.SCUSS1:on. TI.irJly, two ::iesSa;!eS •nth i=.a".!.tl.cal 1n.!ic;J.to-:; 

c :i ... t.: • .e 30:.'le da,,,.· a: .. pe~~d tc ba 1dent1ca lly enci;herec!, 211d C"l direct si. .. er-

-:: .~cs1 t..:.or. !.hc,.1ed thef'lselves to be 11onoalptia.,etic- ··itt:n colu.-ins, 

~,~ .. :. ntr: t.,e lll<:inoa.lphabets cons-tantly, 11regi1larly ar~ unrrecictably :::l i..f~­

_n_ :ro'!l cclwm to colwnn. Fourtl'1ly, tY"O m::ss.:..:es ·n.th identical indLCo~rs 
I 

. 

• r 

i 

, .. 

,, 

I 

- ' 

"' -·~~ffYr~F ,~?~ ~?r!~1 :~~~__.... • > 

I ~' I • 

I • ,-p . I.!~ , I I 

'I 

• ~ • , 11 rr·r ,. ~ - - • ,._J •'\I• l• I -f r • IJ ,, • ' I! J I ..... ,1~1 i 

'-.°':J la ' ~) t!_'ll:o.=J .J i r•- ' ...:::> ,, • 

' ' 

0:1 au·rt1rer1t r\a;,•s (dl.fferent plu~board -a:rran:e'l'ents into the imchino)' .. -ere 

ausolutclJ dift-::rent.. .F'~fthlJ, b:o 1°1e-ssa-ges .a.th different 1ntl1cators en 

t!ie s .... 11e day ( s.;.11e pluE;bcar(I a.rra:n~eMentl .\ere absolt..tel.y C.ifr<?rent and: , 

1-0 "ed no er~· ito'"'rd Jhl.c Sl.!!l~lari ties ... hat.soever. Sixthly, in eaci. ... 11.ne of J .~ ... "' _.. ... J '" 2r ... l~tt~r;., t.' l.ilc:rti"al l~ttor-:;~ ,could -be _a.ent:..cc.ll:r enc::.J?hl..~ec. o;:cc~.., : t. 

u-e 1st 1-~terv.:i.l, t.~.at i~, inenti-cal ,enc-1"'hanents cculd, and ofte~ d::5d,, occu- 7,'1t•iin<'l line of 2t- lettar~·at all :..ntar1als, exce;..t at•the 1st intcrral, • 

al-tnou_,h t.u ... s ~mar.ollenon \,as rare at the,v2d, Jd, 4th and' 5th l.ntervals. , , . 

9. At the same tim~ as the .foregoing !'h6nom.ena ... ere bein3 stucie:i, 

ir.te~s1ve res:arch 1as ccntinu~d tn ~ e"l~eavor tc. astabl.sh prl.Ciarl or basic 

ciph:r sec;.iences of the nature oi' these usually rounc! in cr~.-p~Of:raf.-ns •'l. th, 

.:-o~ t;., "'C co ~i.utd.tors, rotors, and the ll."'~.e, such .o:.s m the Hebern .-and· ..:;nl.ryi~ ~ . 

c:-y;oto.t;rlltms, our ... -134, etc. ~·or 1 t_,. ·as ,;:1l'1C1 ncei va~le that the 111:1.cr l re e,- - ?lo=·-=d .:i. 'llt.l tiplici ty of non-re; ea t.1.n::; kt:.ys of lengths cqrres1 "nc:. v:g to U•e 

l1..!'6 tJ,s 'of t.i.1e: messalies and,, :n.oreover,, tt,eoretical ccnsiderat10'1.s eh .. in:.na.ted 

u d possi::al:.. t:r that rl.r.nin,g l:3ys ., ere beini;;"u~ed. SC'lme-,.t1ere, so 11shou, t.ne 

r.'!.:ustence o! c:ic1ically re~e~tin: !.:.:eys or se ~uences Taust he uncov:J"red· befor5!. , 

solu.t.LO"l coulo. oe effected. But all efforts to a.:;,.sclo::c the presence or 

c,clically rafleating ,seque.."1.ces v.:-::re fr .. ntless. ~ In one and onlv one case 

.. u.s t.h~re .i'otlnc. :::vE::r tt.e s!.1::;l·1tast ·-,tnt or such sec;.uences as were ~bews; 

sou;;ht. ,, In a· certain Enelish text 1nessa-';e the letter !:. y•as fC"und to·-be 

represented 'b." ~, 26 letters a. a"- a.T'other "Z "'as found to be- represented by 

, i, snn aga .. n .20 lett.ers ay,-ay anoth'-="r B was foun~l ~o be represeritcc by V, 

"c..;ln:. 't:.e· •saqu.ence ... 1 V; in tha vary sa.:e messafe the same t1:. 31"aph c;. i J 

r::is fcuni:. tc re,•re:sent t'".ree :;•s 3i.n11.ar:y s.~aced.· ~';.t.empt.& to aw..l t.o ~ 1LS 

~.> !. :~ sec;.i"3nce '•ere .:-usolutel.y ·.mava'l.lin::. In t(ll.S l.on~, e.<haust:l.ve and 

te~ious search for repeated sequences or~partial!y repeate~ se~uences much 

la.Oor a.'ic erergy i,as ex;.·enC.ed but 1 t JO.S ! eali.zed t~t the r:.iffJ c1tltf .... ~ r:s - ... ~ v,~:!. • ,_,_,o to the :i~uc .. ty r:!: t"'c tevt, .~es1·:.te t-·,~ r:n .. _1'-)e:" m"'cl ~o,..rrt,l~ "f 

~~'le 'l ''l.'-l.V~u&.l messazes c-va· 1£.ble ,:'or ..::tLt'l,; rmd for T.::.1ich "':.he ?l~; :i- tc··t 

1:d. L1t!"!"l reco"l:;tru'f!te~. It _==!,eC~ '!~ "Ll:!.1!.Q.rr°t: 1Q.~t. :.:t~t_ ~uJA JiP:..._:ec~ssa.::" ·-~~l _ 

.f;..~~1.J.. ~-~~!f._1.l!-!~ __ c L.l!~~:!,~~~;;,::__,~1,~~~tl::_~--':.q...:::J.:.~~~~-~~ _..:_:: .._~ .... u 1 ..... - s-=-. , ...! ,.. .. a , r;JI. ..... e::·.: .... c c• 1''. ~-.. t J~ ...... 1.rrt: ...,,a._)~ .., - _s ........ t'.. t ,c -~t. ..... "') - '"' ::: -

:it'"or·~\..:.Jn •1--!"ez:.~n~,.-~a r~ tl"_t:_l}_e ¥' .• ~~~ii.;; ··efore _q,ventle. e.:::::-::ten~~~~ : ' 

:;Jc. r.uc=:,:.~-~.ll.~~1g,~s-"cGul,La~·~_t.ec ~cl!. 

~' f "' .. J 10. In all tne tncu:;anJ.. or ,1or.a ~a~sat:es en hand ti.ere .. er..e but. a 

Olero oc..-:er• s i1all' dozen or so cases ·h~re 't•-..:!ra .-ere t .. o, ,1essa_;es o, tha s..i."l.e 

tla/ C:"1C. .. n t.r.e s.s..,e' in ... l!.c:. tc.r. _ ora .than t. "C had "\e·.rar -baen ~ou.ri.ll and tr 'LS 

&.::.. .tc. -ce _ex:J~Ctt:a. 1.1' a :;~·ste• i ,: ... t'i. l~J o~r .:'erent iru.ica tors avai.la-ole fo:-

~-=l~c tacn _eacn d~-. In one case' of 1. •• is cac-a phenC1a"3non -t!.e ,cllcun •t.ex: t. !o .. • 

<Jn-.. ~01 1.:td t ... o m~ssa . .,.~s~-..as avaLla".>le but v3~· li"'tle C')Ulrl oerd1.ma •ave" ":.i"'en 

.1.s '.a~ar::-s-~t.r.s sol.ir.::..o:i· of tn'3 ot"ler .ie:iber· of tl·1~ na.ir or .'il.essa •as.• ?or 

~J.c'& ,a 1st.,od of :a"..t.ac .. d.t. least .26-::::s ic•.sa -es·.all in ,.t-he S[s..,~ ::."~c.hc~ t.:r 

1. ..: c~ t·-~ 5:.1: 1e aa•r n0\;.:0. "le nacess.-I""I c:m! t~~S as C! 'course re'CC ._,izec. f":; 

:.! ~erractly· '1.o!)•~le;s eic""'ec~::\t1.on•. -- ;,,~re r~.,,a..:n:!°d' t:1e ~cssib::.ll~~.r ~r con- • . .-~rt._n_ se1er.sl mes::;a~es '"l.th tne sa::ie ... "l~l.C"a~r o ... t. en :.i~f~rc""t ·s.:1s ~o 

w.e ;;;a11c ~asa,Enr ·::.ile this "U~~ o.'.! ofiatt..:Lt''C looked extre11el: d1!."fi.cul-. ... :. ~., . ,., '""'- ~... ,.,.... ,,. "" 

- ... _ .. _e, "lO v a;p,ea~ _:1~_:el'3S~·-,, _,I -,~· r f,I ·, ,, -, .: .. " '"',·.---~-::::'j"- ~, - ~ 1~ I ,. ' • , , ,it "'!a ,o ~ 1 C '' f ' I! < t! ~ . ., • 

·~~ ~ II bJ 11., ~ -~ -~ ,JfJ. IJ u 

, ~- "''i:· ' - 5 ..... ', _, ' :. ,._ 

" -. 
. ,' 

, I 

11. A mett.od~ fer~ t is com..,~rs..L.cn to t.'le ::a.ne b~se , c.s ceveloreG. 

<=.."lU TiS.S ter;ned "the 1.C.elltLfl.Cat.:;..on Of ho•:ielo_:s.n 'Ihat is, ~n at':.e~;;t -•a,3 

'to be rnn.c!e to estahl1c.11 -~.1at a siven lett~r on a c:rtei.n aa•.r:r-c.nd :::."'Ct'1er 

leb.sr on a di.fferer.,t aa~·.-· ere ,tres.t.~d in an. a.bs(Jlutely icir.:~d .... c:;.l or, , 0 :-e .._ 

o;:.cc1.1rat~ll· ... ~pea:...in5, ,!:'011clar:cu~ .. rnanr .r .,by Ve~.1ac'.1.na ."hen s ... t t.o t1 e' ::a. ~ 

Ln~l.c~tor. T11s convers~Jn~prccess_ is too in~ 1l\e~ to~ex:-.lain in t~ ~ ~e-

... ' 

~.t"ort bu.t~su.ffice it to sry that,d.lff:icult thouch it is, 1t ... as s.u-:::essr•il 

in two cases. Cne of tne::;~ .rielded a SGt of 6 ·~::.:s.a~s, all 1.n i"l.c!i.c=it•"lr ' 

5-3173 111l 1ich could all :>e redt.ced to t•ie s::. "Le bnsc. 'I'hcse, fer-act! L.ha .r-.. -

cial ~et of .nessa:ges from the, study of" "•' Leh sur::c~s~ in soll.oticn or tre 1lhct-.L.na "1.ic:.S finally acnieved. . ' 

12. t1stribut1on ta.bl~s of the letters ccnstitut:!.r.~ the text r~ 

U1ese six n~~S"i~es .ere •nade. It shoulc! ':J~ stflted that in f·,ur of Lhcsc 

... _ six crucial ,ness:- :es .onl:r .!"ra~rien ts of pl .. l 1 n tdxt har! be.en recrYJ.~t:-uctcd, 

' here anri thJre; the cc.nple~e or ,nearly cc.m;;>lo:?te ;;laJ.n tezts of only ~t ·c o: ~ 

these ... six a1dssa3es •had been- re.cor;.stmicted. ;"ic ;J1r.c.r, .. anou,:h' r:k.tn 1 ere· o.ccu.·t.-

latec ... fro1n. these t· "O cc:::ipl,:=t~ly and 'tte other partiall~r recr.nstructcd 11e:sa.::.e:;, ... to . ·fiEld d::?..strib"ut: ' r."l tables : 1c-h, O'l'l care!'..1-l e7.A."l1m•t1cr, ·~isc-lc-:e'! t'le presence of re :;eated ::.:ecuences, lure and t•.cre.' ":"~is, on ::.ente:ri~'?r. "'J, 

1~40, at a"jout 2:GO P.~.r., .. ~s ~he v~r~· first 1nd1c.at~cn. that~a ::i;icces~!'ul ::ittack ,u~ht be rossible. '!'here "ra.s nuch .~xc1ter:ient a.t t.'"'.1..s'fir,st :zlil"'.i'"':" 

of 11;:ht U_:>C'n' a. SUbJ~Ct that ~10.ri for 50 "lc."Ulj'"' "'IOnth.:; '!J~~:l shrouded l.n CO""l_::.!e~~ 

clarkn~ss anJ re.-ar~ed acca~iona.ll·r • l. th :;o·'?.e h~cc..1ra ... ~11"!:it. ':'he natur~ l..l: 

tc.1.e t..1str~·>t1tio;i tabli:..s, re u:~rr .::~ ~o, is also toe 1.mrol-;ed to r.·.-.,la,_..,. l..'1 t; :. '3 

re_Jc.rt, but suffice J. t to 1ndica:te the.t tlie;r st10.'e'l cart.a.1:.n s:r~netrie:::; °J•'.!-

tween the succe~ sive c1-her ei;..u1valents of @ .,.1ven. :Jl.a:in-te::t nett~r .->n~A -:.. '7.~ 

&u-=c'9ss.Lv.e a.J;:J~arances ~! that pla:.."'l-te:.i:t latt-::r J.'1. .. t.b.e c;:rptc~raA :i.::?..c text •• 

lJ. ~s'soon •1s the ex:istaric~.o!' c{clic or s.,urn.::trlc·se uoe"lc-:-s l"e-

,·- .... ·:_u, .:.~L::. 1.:>~ ... • .J.L•e naa.e to. t..ncover co.lplste aasic sec:uences cf 1.•ie 

t~C:111! theoret.Lcally tJredicted., Eut, man." conflicts a.nd i:i.co:isistericies soon 

r!P•,..-1-r~'i, •

1

1.e Le t ,.~ .:'c;ct. L~.<:.i.. !.."...:= crJ1 tocr1 1ic ll: s tL"ld3rl,tin~ t~re ~ :.!'t;:. 

.Lr.~ ·1 rc•'l se'luenc~ to se-:iu~"lce ' ere st~ii U."l":I'l~l 'Il. Concurrd.1tly -'1. t~, tt.a·. , 

"•-erk connect.ad 11th st~al.!:.1t.:;01n: out and re:ic·.n.ne i::.conzistenci.-=s Jn t~.e:lc~ 

r.econstructed basic sequences ran t},e .era<: or uncoveriri~ tc1e/'cr:-ptogr1:.:11-,!i:: 

~ws ref erred to, and verv . soon the . -=n~ra~ .. nature cf the latter oec~~e 

quite clear. All efforts were concentrated U!JOn tne r.!evelo9..,..""nt of the 

Sfec1f1c• l;:.\\S ana. s;.ec:;.fic ~as1c 3equ~nccs a.:-p~icaiJle ~ the in::hca to:r 

ut:J.er · ~tur!.y, viz, 591 ?J, 1":.. th a view to uncov~r'l.n,; all- tt.e c~r; tcc:r't::ih!c 

'"P~l"o111en11 in 1 this ce.se err! then searc''L::.n,·-.... f or ruialo .. ous uher..c::iena 1n Vie .,,.\ _, D ., \ 

case ·or other indicators. Ccr~in ~a:i.:ied p~rsor-.,el frori other sectrr.ns 

.,,ere brou;::ht in to c.ss L3t, a..1~ a cc-nr;1.-.cr nbl~ amourt: or·~nii:ht , i)rk \as 

rc.i."ld da::ira':lil.e in oruer to pus~ t'l-A!,s ~i-;t:.dlr to CO'T1~latio!l a.t t.'le earl:.ect. 

poss:tole :oment. 

, ' > ' 

I 

\ 

T 

..' 

' 

. ... 

' 

I > 

-. { 

-. '" .._.., . i 

" ' 

.,.. 

·~ , . '< 

> ~ 

.... ' 

' ! 

- ) 

I 

• 

, , 
• a,·»l·r~ng the pr:.nc.!.ples of sclut..Lon. by l101olo;s, gui:led b;t \..h~ ·aid or .!;.be 

r~~o;strueted b:sic seqJ.ences. It '"a~ all the mo:-e srr..t.ifYJ..ng tl"iat tl~is 

co:J.lrl be done, &n ti-.e verJ u..aJ t.uc:.t .=innou."lcie1.1ent ..,as !18.de of the ::.si-:rlnC o~ 

tlle 'l'riparti te :. ::r~e.ncn t a:mn; Get .aan;r, ! t.a.ly, ca"1Sl J .!iJ~an. 

15. · ... u1ch '"'-Ork re..:iainea. to oe 'c.one, i·o ever, s.!.nce only thP dat::i. 

a.>:lli.cable 'to ~ut cne' o\..t o~ tl1a r"hola set' of 12J indicators ·rere .? .. t hr.nd. 

~~- sclve t~~ r~-:s.i~~n~ 119 i~dicat~rs a;peared s~ill to prese~t q i~e a 

~ lRr:;e 1iJrocler.1.. '!l:.ese solut!.ons c-rs:.st o~ fl.nc.ins t.:e ::...."'l::..tial :se"tt.:..:-a:s c.~ 

ti.re~ 20-lave:!. rotru7, elec tr ..i..cal cr!r:..)tc :;re_ ic ele:n·=nts of 25 ;oints e:>c ,_ 

and finc.Ln.:; tie c:-tl3r in .rich ll•e-:;e three elements a.re brour;ht :.~to pla::: 

,,.J. thin .::a.ch 1n-..licatur :::;ystaTJ.. • ·1=.h bi...t little s~ac"-:e ... :n=: of ~"le ::£.ce c.:t 

'b:,r th~ ~e:-scnn.:el i:.he"ll.salvas, orn: tl· s ~ro::;r~ssed .. itt:.· V!.~or an.:. a"t tl::.~ 

.:.o.::i~n t sol~ ti .... n'S for ov~r cne-thirrl of t "le l~O inc.icators .are a.vaJ..lt.'Jle. 

16. ls to_ t.he 1necr .. a.'11cs of t.l1e E-:nac"i.ne, .naturall7 t"ie basic ~r!.nCl.=Jles of its con5truction and(cpcrat..ton t'-ere ded.l..ced f'ro1l t'1e C~":.Jtc::·a::h!.e 

pn1~no..ae:i.a-OOSel'Vt.~le l.n the u1essa~dS, n.rnl l.111.':cdl.atel~- plans .. ere 1."ll. t~~-:,.ec. 

for tne construct.on of an equivalent ma..:"h1ne for our r.ur:)oses. C.rcl~rs .f'or 

the 1..1a teri.el for 2 fully au t'J.a .. L ti<: nacrn.nes 1:ere placed and ex;edi ted. · i1:. le 

awai ti:ic tl"~e e.rri val of tr.is m.a.teriel a tia.nd-o;:erated rr..a.c:.iine c.s o.esi 7"" ~d 

' -

b;r p~r&•Jnnel or the J-S section, can-structad b:r tree, and is at. t!is "T-t.:'~g 

bein~ u~ea to a.~sist in the deciphel"'~ent or ~ess~ses. 3a~ically, the 3-.;c~ "~ 

ccns1sts of 13 rotqry, t-level,~ 2-5-poLnt, s ... n. tc.nes or the tJ-pe e.n~iloy~a. 1."l 

cli...toni.tic tele~hon:,r. Ont! cf these. 13 s "'l.tc!1e-s' cont:-ol'3 the enc1:Jher11~mt c! 

t.!1e 11 61 s" and it goes t.1I'u1.1.:=h the s&:ie 25-pomt cycle over and ov.ar aea_n as 

many ti~es as is necessary to encipher the messa~es. It hr..s 150 crossconnect _<ins, \flu.ch, c-s stated Ei.'Jove, h"".d b~en established lon- c:.go. ! s t.o 

' ~:·_ 'J .. e,....,c __ a -"".l::. .... ~1 .... _i;;-: .. -:-,_ .. L::...~-: j~:, ::::. : :,~ l s .. _"'c ~<"' _g,,..- .. "!: ... _ .. 

banae havin(. 5~0 cross-connect.ions, •'lak:.n? a ... total of 1 1 500 sub-cJ..rC1.1l. t.s. a lcll..l-

.t..~~ fer ":.he ~""IC-1._ .. r::::-.n"r~ er· an:· c..._vi:in letter. The arrE'"-e"l.e"ltc; fcr,r-rv.-"e-

• i'l-i; t.bese sn.tcnes is such that for c:. •·iven :.m:uca.tor, say ~Q..~4.J, baP"_ "'lr......i.-

ber J steps ccntinuqusl~r, ,'bank nUJ11ber 2 steps .:;:tee !or- every 25 ste_ s c... :>.:r ... : 

r.'miber J, anu t.=in~<: nunber l .ste~ts once for .ev.=r:.· 6:C:5"' steps cf be...11.,, nu.-~e:- 3-~ 

TJ-J.s t!-&>e or ""lotion has ">een des:.~nnted as a 11 ;21n 'U.Oticn. :'or C?-i.Oth~r :...,-

c;.~cator the or.!-ar of tt1is ste~J')J.nc- uia.•r be~ ai:f fer..ent and ir' all t.1~re r..· ~.:ac 

to ~e 6 ciffercnt types of sta?p~~G: i-2-3, 1-3-2, 2-1-J, ~-J-1, J-1-~, 6 ~~d )-2-1 .. Althou::;h t!1are are l:>O diif-:rent ::!..'"'d1cators ~'1.ere a!"e c.1J..:r 6 ~:..:.!'~!"e"'l~ 

t.:,';'eS uZ !:"O °tl.On or S l:.ef.1 .t- 1n:::; Of tne three C l~.1.::r:..n~ S,-_ tc~:es J SC t • ,;: °t ~ t ~?­

~ears t..~c..t e:J.ch t~-pe of .notion ;u~ 't epresant<>d by 2~ ::.irr~rent J.rc.~cr .. "".r=-~. 

1111a t c.if fere'ltia tes one 1n1hca..tol' fro . ., another .. i tn:.n :men a so3t or ?J 'l.m.;i...-

c&. tors &re trie relative start.in:; poi."1-ts t.ithin &.J1e thrae o~trks cf S\-:..te1L~S. 

';hese st.a.rt.inc paints a..:Jpear to have bcel"'_ verJ carefully selected ~c.. .:1.s t.o 

pr.dcluue or reduce tJ1e ,;.o.::sibib.tg of "overla;is," tnat i~, tue 1ll'Olluc:'lor er 

t.~c, '"-!:Ssa.;es ' J..cn :::.n .. hole or in_,p.art nr.ve bean enciphcrdd o:r irlenuc:r::..l lte;-

L"'l:;" ele..1.ents •l.n itlantica.l seouence. • Cnce t..1ese factors concerr11r1.:o all _.,_ 

a<:a tors hav.; oeen estr.ul i.::.l1e1, o.nn our m.achi.n:; is -1:-:. opera.Lon, th£. rdatn. 1~ 

o.r B-~a.cn1"1e i:i"!ssaGes .rasol .. es it:Jelf i.'1 ...o t.'"le estc::.bl1sh .. "'l.1:nt cf tre •• a-~:· 

plu;:hoa.rd arrcn,,einent, tl.at 1.S, the oraer an::!.. id~ti.ty of the .nteo lcacl::.r..,r: 

. ....-rcu; the keyooard into the cryPtcgra:Jn c:.:r;.d thenc~ out or th~ er~ p:.c~:.·D._:n 

into the ,:}r:.ntin,s unit. Cryptan&l!'tic procedures for Vd:::; purpo~c 110.\"<J a.1-

reaay oe~n established and test..ed..__,so tnat tnis s110uld not be a serl.ol..s 

•t .,..:;.' 1~-,~ "';'" .:-::; ~,\ ,---).r::=x= .... ~ I' ,. I o" I '"" ' tr .. 

• -":> 
SECRET 

' -, I 

~, ."";•ven a long messa;;e er several suort ones of the same d-a.te, :-ro-., _e.11. .... .... solut~on s!lould be possible in an expeditious aianner. 

17. '!'ha so1uticn of the B-mac"lllle has, as a concomitant, thro.rn 

cori::iidcra:tle lisht upC.'n the mechanism or the A-'Ilach"'...ne nth the result 

t.~at. cur ;;-resent a-112L·'n ne w:i.11 be modified :in t.'le light of 'tnece 1.1sco\. "lrles ar.u ~fill o.a·m&Q.e more e!Ticient.. The whole situation vrith re~pact tc 

t!.e ci;;her m.act.ines em loyed by the Ja:;ianese Foreign C r,fice no .. a-::.pea!"s 

to be ."lte~ated into a. consistent :Jche.,e of development frn'll its carli~st a.na sJ.mpl~st bes1nn1n~s, about 1930, to its present ~uite con~le~ 

f(..r:n. Proble~s ccncerrang the J\--ia.chine ~u1d c:.uest1.0:-s for "'1 .. ich lc~ica'l 

ana ":-ae.sunable" answers could not be fou."lri are noi1 explainable on the 

d.a"!l:)le grotmds of the type of cryptogra:?hl.c mcchanis:n e.n •. loyed in the 

ec.rlier ma.chines, ~nich seems to be the rotary S\n.tct used in auto~1tic 

~~le •• hon:;·,, rather than the revolvin~ cc.iunuto.tor e"t!lplo~-ed in our :;;>resent 

J..-.r.acm.ne. 

Part II. Credits 

18. The successful solut .. on of the B-machine is the cul.,1inat- on 

ot 12 aontJ:.s of ~ntensive study by ~ group of cr::-ptanalysts and assistants 

:1orking as .a hal"li.lonious, well-coordu1ated and cooperc..tive teain. Cnly by 

such cuoper~t,on :?Dd close collaboration of all concerned could the sol~­

~icn possibl.y- have been reached, and the na.~e or no one person can be 

~electea as desarving or the ~l8JOr portion of credit for tt.is achieve~e~t. 

':'le parts .a:>layed by the individual me.'D.bers of the tea.'11 may, ho~·ever, be 

ineica.ted. 

19. 'Ihe Specific direct:.cn and COOrd"nation Of all Studies On rt'l-L1S 

-::reject ,•as the JOi.nt •-rrl• Of ":r:_~~~,~:!..:rst rr[._ '· :.:'c;-let.t 8..."lC'. !,s~:.s"t.am, 

i...r. pt.c!.:' a.l!!~"t ... :Obert O. 1',err.er. · Their inaefatigable labors and brill i.ant 

anal:,rtictl .·-or1< testify anQ are a crerJ t to ~ ~; :- c~7":.c:r.El~·~ic sl 1:1, - .-

~ "': cl l e:-:._?en.en.ce. 'io tneir .:;o'..'1.t 1 .. ir':}ct:.on and effcrts are d"G.e ~he P .. _ 

:-E~~lj f:-iti~l analy&1s or the cr:rptograF1ic mechanics underl;,rin~ the 

operat:.on cf the B-.macrdne as e. •-.uole, the theory or its operation, and 

tl:.e de\·eloP::a.:mt anc! solution of tne 1161 su at. eny early date in these stun-

_es. 7'1e;r ?.;ere al.so extremely active in puslan;;;;: the solution to a successful ccnclusion by orga~izine a.~tl ~irecti.~~ the reccnetru.cticn of the 

cevel~pm.ent.s. or t·i.rings of the sm tches for tne "20' s". Jtmior Cr:J?ta..'lalysts ~=evieve .:... GrotJan, Al::>ert • 5.riall, and .:.a:nuel s. Snycer cid 

~c::t S..'-Cellent wcr1:: i::i recoverinz: the ''61 s" during .:na.."'ly- rc.onths of a.1--pa.r--

C"'ltlj ho;.eless effort.. In t::.is 1e.rk they .. are occas:.ona.lly a.ssist:?d b:· 

.:r::·;tozrt.;i:.ic Specialists Cyrus c. ~tur~l..::1, Jr., KPnneth p .... '\.llar, --anc. 

:.lenn 5. ~udig. Of U1e latter tv.o •11ent.!.oned, it should also be stated 

tuEit. t~eir Vdr".J' large output of ,crl-c: Ul .,ne decod1n5 of J code "'l.aterial, 

.. _:;:o.,s:.ed ::ia-rt ti:ile by oth:::r namo~rs of tt.e J-SectLor., lifted muct. c! ~".: 

!.~:&v;, 'b~rc..en cf •t.. is absolutely necessa.r;,r current trc.nslaticn "Crk rroil tr·e 

-8- SEcr~ 

~ 

l 

1 

i 

j 

~ 

j 

j 

-'I 

' 1 
I 

/ 

I 

.. 

.. ' 

.. 

' 

..., ' ,o 

. 

f 

i 

i 

I 

. .... ..., , ' ~,. .. ' ' ' -~· ' 

the same date, 

._ ' ,;, B-n-Lo'S', I 

~<.cl .,i: C .. f f-ha.."ll., • ~ne htis,.. as a concomitant, thro"r.l 

~l t.h~ ~\\' , ~e ~;' ot the A-mach"..r.e ...r~ t"i-the :result 

....r ·~.: 1nA \'fl"~l.ent ... ~lfied in tnt= 115ht of th~r.·~ ~1scC'"'""r- ......... r0 t)Cl t / "t.h:/ The vmole si tua:cion vd th re:lpect to 

ir,y,Jcl ""+-ent 1"'[ 2.nese Foreien c i·rice now acpearc; l .. , ·1 • 

t- cm1tt nbov ·• ,s"rle of develcpr:ient from its: car-

,.· .... :1u1rl •t1 ; ,\-'"':'.., ~ 1930, to l. ts present (!ul. te con-;1e:; 

J.'J 1 r1iJ, \I,,.. net ' ne a."ld questions for -:i:l ich lo~iea.l 

,t'5 c<lll! ,. cr-pv rou.'1a are non e~laina~le on the 

tys;;!J ~t 00• to~ ,- a.phic mechanism e.n,t,loyed in the 

, ... • .. "'m•r oln \e ratar~~ sntct. used in autc:ia.tic ",. ~ I •-.-- ~.. t,1:U l "' cc.mmutat;!lr e::plo!red in our present 

**.to ~*** 

Part. 

1. • Credits " 

11lut10 .. 

' I 

$:'='5ful ~._dy b· "'l the. B-:nachine is the cuLLinat-.on 

,. ~'·'"1ve A i-coo~ 5roup or cr.~=ptanalysts and assistants .. / ',/.!'>Si Ytel r llatc •·uted and cooperc:.ti.ve team. Only by 

'' ' · e].ojj!l ,..,_ ed ... :;.on of all concerned could the sol'l.i.-

11· I " 1vJJJ J ... • th f i. _en ~ra ~ !aJO. e name o no one person can ue 

I. o! t.t.-; vid112- ·1.rtion of credit !or this acttieve"llent. 

tile ind1 .. '3':1.bers of the t.ea:n. i"l~y, hov1ever, be 

. .,. act- r.-· r•" '' • ... - -t'\ coord-1..,ation ·or all studies or tt.is 

J• If"/ 

• \1 

.- I .J l 

i •J.f,, ..,,,;rt. ''~ ·~· "'al.vst Fra.."lk S .. Ro11lett ana Assistc:.n .... tl. r, ?,.rtb ~:,, :_,.,.- mdefatigable labors and brill'lant ~~~ ~ 

t!J .... '~r JP" -:!it to t. 1.a-Lr cr:;tar.E•lyt.i.c sr..i.l.l, ··w- , ... , r~ct-c" "'"'"' e .. r,...r""s ~re~ e ... ,.~ ,... ... . --' .. ~ ~o ' J' the • - • - ·• ........ .L-"' ~ c:. _... 1. - - -

;•}- .. c '_dl,,~i.• I:/, 5 .,' ...:.~togra;;:'"i-e 1:1.echa'nics under.l.jl.nc tr.e l ... ,- J ...... ,._ -

, \," '; •i.fl.C' t:-~~ 11 of ~ '9, the theory of its opera.tion, and /' ' • I ,, , d ,' '~ 1 .~ cc,!!':!,-~' .dly ~ .. "o's'~ at ar.y early data in these st'!! - -.. , :.P ~r;:~ .... " -·e in pusl.~ tha solution to a success- ' "J. I I. JI~. g.:. ... 

L J,J. ;t,t;.·C;.-%- the S- -ecti.."l; ti'e reccn"Structi.cn O! thei" 

• ,. .,.e·, ~..1!' 1an ;._ : "!.es .for tne 11 201 s". J\mior Crypt-

·' -'"'' 1 , .. , ,,,,. ' v""r-.. , ·~t - • o:i ~ tl all , ar. d ~m1.1. =- "'Ue1 _ ;;,, ('! • S n yder ... ~id ~ ~J ...- -· • t6 ' \ , 1."'1 ~~""= t.cis -g ' 1 s" durl.D& many rnonths 'Of &.f ?a.rt•, ,,.·t., : ,. ~; rru~ · they ware occc.s:.ona.lly assi.::;t2d b:' 

f !. J iJ.!.f 3' ..... '3 -t I. t. t.er 't.ur~J..S, Jr. " Kenneth n. .il 1er, a:i.c. 

1 1 f.~fi .!.· .t o! ·lent.!.oned, it should also·be t:tatea 

'"1 /',•,." --· ' r..:. ~ • "!.n i..ne aecod1n;: er J coa.e "1.aterl...-.l, I~ i. ••W4il~. - 1 ' ,,., ', ·,;: itai- • • o.r tne' J-Sect.1..or.., lifted ::1:0.ch -c~ :.'.: .,,, -·' ' J. ~ ' ~. i-5 ;,,. /'?'.,. JSS&ry ,currer.t tra.-islation Yvrk frO"l- .. r~ 

t 

' \\ I .:1, I'''-- f

0 .,l_ cl 

~it L'·'.1,h\ii , l.!dJ _.!;_.,J \l~ 11 

a -

--· 
e. 

... u{\~ITTl~7° .. u:JLJJr rw~l!J;u~tu. s~o~lcers of the other ~em~ers cf the J-sect~on, th~s g~vi"lg the latter 

!!lore ti.ne tor research on the .3-'"12.c•1ir.e than "."OUl·i t.ave other,"l.se been 

:>ossible. For the ori.::.nal sug3est~on of the elect:-ical tele?hone s 1. tc,..-

ln.; .nec1":.anism. for duplicating the enciphernant of the 11 6•s11 , the des~;;" 

a.."ld. con:::truct1011, in colla.borat.Lcn · "J.. th .:.r. i-:.o .lett, assisted b:· ct,.,er 

.:.e.r:bers o! t!"e ss~t .. on, of t:-.e T"\a.,.. ;me foJ.· ..d.eci.>h:?r!.n:;: tho 11 61 s' anc! fer 

excellent ?"Or'-:: in the a.eciphJrnent of the 11 61 s" in current traffic over 

::J.arr/' :C"'n~1s, C.:j-ptc:;rapnic ~peci.a:ist (no·'i lst k .. eutenuit) Leo iti:.\sen l.f:i to 

be ~antioned. Fe also supe!'Vl.sed and ass~sted in t..~e conetruct~on df 

the ha..'"'ld.-oparatad 5-maclr:.ne desi.yi"3d. b;· the c.ryptanal:rtic std.ff of the 

J-Gect!.on; .i"l ti.is latt~r ~roJ::ct Jl:Ilior :r-~?tanal;,""St :a:. F. ~aa.rc'3, ~r:::-Jtosra~hic Spacialist £d~~rd J. Ea11~1ns, Sets. -_lder End ~o~ also assJsto~. 

In tl".is ccr.nect ... or:., it sl1ot..l.<! also be ::ien t.~orie~ t:r..at the shop fEc1l1 ~ies 

or the :-.ad!.O LG.boratcry, ~·avy Ya.rd' . .ere kindly plr.ced c.t cur C::.s:-osal ..... d 

carte.in "!lE.tariel !urnis'1Pd thereP t, throueh the courtesy -0f Co,r.nandsr Lf. 

~&!'ford of the Co~lU."1icat.Lons Sect.1 i t;r Group, Cffice of ~:~.val Co:l.".i'l.&Ilicetions. Tnis ere&tly fac~litated the cc~struction of t.tie hand-o:erated 

a.-.ma.chine. The exce!len~ '.rork of Tabulating ~.achme Supervisor Ulrl.ch J. 

f..ro;rl and Cr:1ptanalytic ..' ide i:..ary J. :Amr.ing i.."'l p~rrc.rmin£ countless tai:,-

ul.2.ting machine op=rat::..cns desarves '1!.ention, as v;ell as th.e painstEkl.nf; 

1.0r~; cf tne vc:.riou:s card punch oper&tcrs under t..lieir s'\..pernsion. ·.ass 

:,ro:ien burg per!cnr..ea and asf.is.tea !n r.iany clerical jobs or routl.ne and 

special nature in cor.nection · "l. th these s tL.dJ.ee. ':he work of Resea.rct· 

J._"lalysts Johl" .a. c!urt a"ld Pa.1"1 S. Cate muf't be mentioned in connection 

\nth our efforts to recor:struct the texts of mess6.:es in Ja:-ene<>e. Tl'.is 

difficult -.,ork had to be done in 'ihat little tl.!11.e could be spared froti 

t.~eir reJ~lar and arduous duties as trarslators. The .or~ or Cr~rptc~ra;~ic 

Clerk l='ra."lces :..::. Jarome lll Jla.i.nta.ining tl .. e f:.les or the ir..tercert traff:.c 

necessary to t..~ese studies proved to be extremely helpful; her eve.I"Juay •erk 

in oparat1n~ the 11 61 s" deci=1r.erini mac:ine was painstaking and accurate. 

To Cr:.-,tographic Clerk 1'iary Louise Frather credit shoulfl be s:i,,~ fC"r .L,.,.,. 

t. .... ~.:..ii "=c.l:"':.::g of t:le ro::coz as and .:;.no.a:-: cf a.11 !'lessages; it v as al.so !i-":ie v1ho 

i'ound the para.1hra.sed K-1 message mentioned in .t>er. 6, and ~hich plc.yed an !-;::>c:-~.::.....,t ;:.rt :."':. the !':.nal 'ere:.!~ :.11."!.c the syst~. After t."::.e :.r..i1.1al :::pl .... -

til.n o~ t~e rr:c. 1 s 11 hc:.d =:aan .:iade tbare '_s ~rea":. pressui·e to hurry tne erk 

along as i'ast as possible. In addition to considerable overt'J.m.e vrork by 

geocers or the J-section, certain personnel from o~.her sectl.ons er t.~e 

s.1.s. i'iere broueht in to assist. 5o:?le or 't.'"i.e:.1 pertorned this .. ark enl:r 

ts voluntary overti..T.e. Ir. t·1is special assis~ance t.11.e na.'":les er the followin~ persons are to be L'lent::.cned: J.ssoc:::..ate C?"l?ta?!alyst Abrahari SL"lt'ov, 

Assistant Cr,,rptamll.yst Lawrence Clark, Jun:::..or Cr:tptanal;rst ~elia. J...nn 'l'a~rlor, 

Cr:,a;.to~ra;:hlc Clerk "'7ilma z. Berry:1an, a.ncl Cijrptoerapn1c Spec:.alist E:a·1•ud 

E. Chris.tapher, ,Jr. 

T'le vi.gila.nee and exce1lent work done by our various moni~or s~­

tions in interce1=tinz and cop;.ring the nece!saz:,· traf!'ic also de::;erves 

-s;;ecial .:nc:mt:.on. The assist.a.nee rendered by G-2 in obtainin: certa.:..'"l ca.ta 

has alreacy oeen 'llentioned. 

The unc.ers1gned .iras dir.ected to partic:.pate 1n the "3" r.iac'line 

studies i."1 Au~st 1~39, and from that tuie on these studies 'V"ere under tis 

.:ar.eral supervis:.cn, at the sa.-ne time that he carried on :scrne of the c.\..t1es 

.!"ro-: 1tr ich he hac. not oeen relieved. this general sup~rvisi.c:i - ....,. 
I 

I 

I 

he also directed and ::.l.:lselt conducted spec:.al stl:.dies ""'i. th a.ttne\-: to uncoverin!l the CI"j~togra.Jhic princJ.ples underlying tl'.e B-."n~ct.ine. r!e in.sher. .,,. 

to ta.Ae t.~.is o;•.1:1crtu.."l.ity to indicate li:. s. :rat_f1cot-on cf tha de~or.strt.t..c"l, 

bJ !-is assists-nts, of tr.eir crasp of the er -;:ta.."lalytic techni~ues tau~ht 

t::e:i as a res-1 t of t.heir !'artic:..patJ..on in the traininc: afforded by the 

S!.;;nal !ntelligence Ser ool, as .··ell as nis ple&sil!'e at the Tanne:r :;,.n -.~11cn 

t.1e ir.divicual file~bers of the ~eEllil. earnestly ~nd ~holeheartedly collabcrPted 

in t~is Joint effort. Fe also 711.shes to express his arpreciaticn cf the 

im?ort£nt assis"':.ance rendered by the Cfficer ll1 Ch::.ree or the Sl.gnal !ntellic;ence ServJ..ce, and his co"1mission~d assistants, in ex:;;:edl.ting the ,;:.rocure.-:ient or personnel, sup:-lies, and s;.ec::.al 1nforr1aticn v'hen needed. 

I 

October 14, 1940 

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C(J)~ o'.iJ~~~ ... •·4-< 

.-illl.C F. !i'ried~E!?l, 

irincipal Crj-ptanalyst. 

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