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M~fWTES "&pt ~-Tnro w~~R· it~~~~-.·. · l ·.December 1947 

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-8:~ck-mbe·~- 1947 

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A conference of' ASA and Na\ty representat!ve~ on the subj'~~t ''.-' :. 1 Of CC~ moc1r1cation v~s held in Room 117 Hq., Arlington Hall 

Sta. ti_on at 1330 on Mondsy 1 December 1947. The fol lo,_\•ing iJere 

present': 

ASA 

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Mr. William F. Friedm&n. Cha1rliian 

Mr. Ji'l-ark Rhoads -

Lt. Col. Charle~ R. Rig~r 

Major J. G. Moak 

Dr. s .. Kullback 

Z.-i.r. Leo Posen 

Dr~ A. Sinlcov 

Mr. F. C. Austin 

Mr. K. Ku!.'l_r1 

Capt. L. F. SaYford 

Capt. M. fl. Gerin 

Capt. R. o. Hansen 

Capt. J. S. P.i.a.rper Capt. L. W. Parke 

Capt. A. M. Patt.erso~ 

Cocdr. ·P. 'Ir!. Se·iler 

Lt. Ccwdr. J. C. Ra!'g1·s~1ves 

Mr. H. Canpai._sne 

Mr. R. H. Shaw 

Mr. L. D. Whitelock 

As.:.14 

AS-...14 

AS-23 

~-S-23 

AS-70 

AS-70 

Ao-80 

-AS-83 

AS-85 

. OP-20-D 

OP-20-Y 

OP-20-K 

OP-20-H 

State Dept. 

~CSL 

OP-2C 00Y 

OP-20<N 

QP-.20-K 

B~hips 

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!·i::-. Fri€~C.:i cpcaed the ~eet:tng in the ab~ence of Colonel ~··, 

:b:;Bs w-h-:1 vas out cf to""m_. ~na pr~sentcd the ASA is 1,!'ie~polnt rega.rc'.- 1•;;~~ 

.. l::; t~c modif'ica ti on of the CCM { .3Ce Incl. l}. A gt:!:l.e:.:--al discus- ! 

:-1i•;r1 follcn.r.sd rega:-·dlng the d1 f.ficul ties involved in the CCM modi.=. ---·- : :'...C~\t:'..on :pro;:;!"'am. as opp-:n:ed to 'th.:;, dil:ficulties of ·rm.rlring and 

::~trlouttne rotor2 ~or~ frequently. 

Capt. Safford stated tlmt in his o~inion ·1t woul~ be a1visablo 

i:.o !)o:>.tp·::me a. final decision in raga.rd to this vh01e mat'tar :for , :;.t:c--.:t onz montr: lne.~nuch as some changes are to be ~xpected in both· 

.:.~v-:;- and f'rr:i~r h.i.((.1 ccz::::..-rns.nds. For that reason he felt, t.h2..t, no 

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-i , \)~tmen't~ could be_ ma~ a.t 1 the ~~nt. In !;.he .i;neantiLle the 

1 · .Anq1s proposals vould be st?died..b:r ~dmiral -~tone . . ·' . ~ i . ' . . i 

:.· = < 

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·. - This sugge3t1on b:r _C.o.pt~ Sa:ff'ord met v.1th the approva~ of' . •11 pres~nt. 

Junt bef'ore the clo3e or•the meeting~ Ca_ptain Safford stated . t}lM.t Ccnm:ia.nder Seiler "ttas -.,;ork:'!.:ug on a new CCM casket 'W'i th j,Pl-lil'OVE?d. 

· contact-assembly that vvuld give more positive func~1oning of the 

_st9pp1rig-control contacts a~4 hence more reliable operation of the . OCM.. The ne".r cont.a.ct-assembly would include back~contacts, and 

)" 1t-abop te~ts indicated that.the ba·~k-con"t;a.cts •ere reliable, we 

·' coμld go to a Jhore cOt:lPle~ 1'?¢t1on of the 5·rotor machine • . ,. • I 

. _It was a.greed then to adjourn the meeting, subject to call ~oa,.~he Navy. 

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. ~,ASA: Sta_te,ment on CC:M 

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~~~~J~ WILLIAM F. FRIEDMAN . . 

Cbie:f' $ Co..-.mu.."1.ications Research 

ChaL.""1DB.n · 
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Conference ~1th Xavy on 1 December 19 ~7 

l. Ba~kground: 

Almost one year has gone by since our last conference ~ith 

. · ·the_ British on cryptographic equip:u.~nt for use in Gombrned Cor:mmnications. At that conrerence the p1.,incipal subject va.a the possible 

,: --;f.mprove;ment of the COM to Increase 1 ts ~ryptogra.pnlc sec 11r:!. ty. The 

: --BA.V7-Ill"'-PD08ed at that conference ~ertain nodifications involving . ~,the .u~ o~ rota table ar,d variable earn ccmtoun-; on the rotors :for . . ·, ·the Cv.1'11

.' s.. A certain amount or research und d.eve1oprn.Gnt ·,.7n,3 under- ._.·•·~- ·~-.taken by the Navy, an~ after a.bout 8 months 1 t developed tb.a t the 

:<'.- \ ·-·~QPo::Ja.1 ~~ impracticflble and could not be "'rnrked Ol_!t so as to be 

: ·, ±-', ;~at1s!"act91'J in a:P;)lics ti on er us~ge. There·11)on ot:hBr m.")rJ.~. ficH t:tot~ 

', ~" ;;vere propos~d both by the Army and the navys these involving char:ges 

: :.'' , : ';1n'. rotor tf!f)t1on so as to eli?nina te the short interna 1 cycle and 

_ .. _~o ll'.lak~ Cl.7P~analytic solution more difficult in other :re::ipects. -~ ~-. ttbese pro:pos41s w~re thorqughly studied. The Army proposnl was 

·.>.::...t'Qund. objectionable by the Navy on mechanical grounds. · Thi3 left · ~._'.',·ihe_ ?ravy ~op9sal as tt_e only one remB.ining. 

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· .'· '· ! ... The Army Security .Agency rJB.s carefully studied the Navy pro- ->.'~~·· ·.:ttosal for· modifying the CCM and finds the folloving objections 

, :}: ;:~~;~_:,thereto: 

' .. ::: :-,_· ·.,tl.. A1though the proposed. changes vould increase the crypto- .. _·"~:Phic s~C1_J.r1 ty of the ma.chine, th.is in.crease vould not be of' _ ~- .. :Jnlf:f"1c1en/t ·degree _to ji::.~1fy their adoption_ in vieV of the pra.ctic.1'.tl 

-:. :· :.d.:ttt'icu"l ties that woul~ be encountered: 

:,-~'.;/;·_,_· .·· .. :/'{1) .AS~ _deems ·.it -~oubtf~i that the proposed mcctfications 

. . · ... c~ld be _fucor_por~ ted :tn tne Eri ti sh Type" ma.chines. On this ·--~.-:-;;..~point th~ ·wavy bas repc-rtea informally that the matter has been 

. ''.i?Si«t.u<Ue«f r,9! s?out a. year,_ p\i!'ely on paper, and that the idea has ;. ~~not,1< l:J,~~n VO!"ked out 1n tl .concrete model. The Navy thinks it is 

'. =>~:~~~p·oaJ~'lble t"o 'make the c"r.nnges. fp. the Typcx but admits that they vould 

~ ·_ct:~~~~t ~i~~·()iG:~~~; l!~t VJ~\l~~Y;h~~~i ~~~~ ~~:i ~~~~ :d~i~~~;~ ~~=ar i c :~~~-- _tt·~is v~cy d.oubtfu_1~tf _they ~ould be v:tlli.ng to undertake ~- - '.~· =-:Bf.1Wojee:t:-fnvol_vi~g th~ eXJJendi tu:re or a great deal of' money, for 

:·. -iW~~eh oD.1.y m1hilnal benefi ta would accrue to them in a :machine soo!i 

:. ~ .. '."'··:.f\o be"'""a1scard'ed. ·, · .. · 1 · 

f . i . -. ,~-; : ... c • : "1ff. -:~ ._:~( : . . , . ~ fl1l rflril rn ... ;---- [ ~t~ /~if~ .. ·: .. :. ' . . . ' . L. .. INCLOSURE ·! I' j ~-:.. 
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(2) Even if the roregoing point vere found not to constitute a difficulty and the modifications were incorporated in 

the British machines ae well as in the U.S. machines, or even 1r 

the U.S. services undertook to furnish the Bri~ish enough machines 

:for Combined purposes,, it would take considerable time to test 

the modiried machines in practical operation, to insure that there w~re no cryptographic, mechanical, or electrical defects arising 

from the cha~es. _ As the CCM machines now stand, we know that 

mechanically and electrically they are satisfactory and stand up 

well in operation; cryptographically we know where we stand, as a 

result or several years' study of the present arrangements. But 

we have not bad any lengthy period to.study the new proposals for 

motion and reversed stepping; it is impossible to forecast vbat 

unforeseen cryptographic weaknesses might be ur;CQv~red by :further 

intensive _study". 

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(?) In executing the Army's SIGROD prcgram, it bas been 

nece:3Sary to use ·the SIGAMUG. These components "Were the ones 

originally used to convert the SIGABA's into CCM's. The SIGROD 

machines resulting from the conversion can still be used as CCM's~ 

when CCM rotors are provided, so that the Army has not lost anything. in regard to rac111tie3 ror Combined Col?lltunications by virtue 

of its SIGROD program. But to incorporate the proposed Navy (or 

even the proposed Army) CCM changes into the SIGROD's "Would mean· 

recalling all the SIGROD's which have already been i_ssued and a.re 

now 1n· service, thus putting the Army back to ~ractically where it 

vas over a year ago in the SIGROD program. Moreover, the Army has 

been endeavoring to completp the,latter program so that it could 

commence on the very urgent program or rehabilitating all crypto~ 

equipments .being held in var reserve, a program which has already 

been delayed unduly. · 

', b. The ASA believes that while at this moment the incorporation 'or either the Navy's or the Army's proposed changes in the COM 

appear.to offer the possibility of' currently improving the CCM 

cryptographically, this improvement does not even now appear to be 

quite sufficient to eliminate all questions as to vhat the security 

ot the so-improved OCM ~1ght be say five years from now. We knov 

now that a theor~tical 3olution of CCM messages would still be 

_possible and ve also agree that granting that there vere a sufficient desire to make what is theoretically possible a practical 

reality, by use of many people and analytic ma.chines, daily solution or CCM keys could be achieved. Thus, nothing substantial or 

of long-term benefit would be gained by modification of the CCM 

along the lines of the ~avy's or the Army's proposals, which 

involve mere cb.e.nges in rotor motion, ~th or withou_~ reversed 

stepping. • ·· ·.-

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. c. In ccnn~ct1on wi·th the lti.s.t-mentioned item, reversed 

etepping: the Army wou.ld like to point out one thing _and to query 

the 1·!a. vy the:£' oon. In emua.i"king o~ 1 ts. program to Pl"oduce CSP-2900 

mach:tne3, one of' the motivating r~ason3 there.for va;:; to h.av6 one 

Illllch:ino ropres~nt,iri?. an improvcii.;ent on the ECM, concerning •hlch 

not even the British ~ould have an .~dea es to its. cryptogrep~ic 

naturf:~e One of the p!'1ncipal f.:;atw.:·es of C~ P-2900 ·.m& the int:rocuctlon of reversed stepping. The NavJ pi•oposal for CCM modification incluc.1.es tbis very .feature cf ,.-a'.'e-\11:Sed stepping. Is· this no"t .. 

inccJnsistent with t.hc b&slc i•eaEo.€ fol' pro11-:;cing CSP-2900? Of 

vhP..t anticipated vnluo •·ould the CSP:-2900 be if the.s.a.He principal 

chnnge vet'e embodied in. the OC~'? · 

d. The ASA has recently conEl:~r~ered various modi:fios.tlons of 

mo::•o radical na 1 .. ure tha.r. those pr-cr·o~e0. either by the Army er· the N~vy thuc far, and flnds that some of these more l'b.dical mod1r1ca-. 

tlona e.ppear to be :feasl ble, or.. ps.per at lea3 t .. But the ;,ractical el!!~'odimcn:t cf these riodi.ficaticns in an operativd manner in the 

ma.chines would involva a certnin umcunt of .rssearch and development, lln<.~ ASA cannct even sugg.est.. undertaking such res38.rch and develop-

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~cnt i"cr the folloYlng :r·eanons: · ··• · .~ 

(1) 'l1he .formal and orosd directive of the Research and 

Developm0nt Division of tha General Staff, ~epartment o:f the Arrrry, 

'in respect to rc:;::ic~Y-ch and development ls the t no funds or· effort 

be expenC.cd in tryi:-;.g to imp::o·1e e:tisting equip:w~;n"!:. by me1~e: ~odifi · cations t~0rein. ~-

.:':·t •. 

{2} The conm~tments of the ASA and specifically of the 

Research Labc1•a.torles Diviaion for research and developfile.ut of 

equipment for the ..'\1"'m:r nntl for th8 Ai1• Force a.re such th.at. no :fur·· 

ther projects can be unde1•ts.ken wi thcut jeoi=ardizing t~he projects 

which have alreacl~/ been authorized and which have tb.us ~n:r• baen 

seriouoly delayed by causes not under ASP. control. Very olose 

scheduling has bce~·nece5ca~y to k~ep the~e projects go~ng in satisfactol"y m!lnnei- ai1d the position in this respect is rather pracar1ou111· 

there belng littie leeway for dlsruptions vhich :might result r~om 

introducing any new projects, no m.ltter hov minor th:ey may u.ppear. · .. -r: .. ··.·.J 

· (3) The rehabilitation prr)grs.m assigned to the Secu~i-;;y Division of .ASA is ~t present far ~ehind schedule. In fact. it is 

so far behind that an emsrgency at any early date would find the 

Army and the Air Force with an insu.f'ficient numb~r of usabl~ cipher 

ri?e.ch1nes to perm1 t the uae of any aingle one o:f the va~ious types 

or equipments for general CO!!l?llu::tlcation. The Security Divieion 

vill shortly beg:ln an intensive prog.i'a.m of rcbabili tu tion to remedy 

this s1tuat1<;>n and any delays i11troduced by modifics.tions or changot:. 

in ::J.ny or our .rr.a.chir...e vo·J.ld onl7 cause f'urthe.r postponewer ... t of ~he 

vhole program. It is for this reason that the Security Division 

cannot und.ertake any :project or modi:fying Ar;.ny CCM Ll.!lch~nes. 

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,.. - :; • .ASA Recouiil!~naa t±onsf:~ ·.. . .

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. .a.. ~n. v1e .. .1 or th~ f'Liet th~t the: l.r'!.!IY f'111.ds .th" ~C.VJ" 1propose.l . ~·tor CCX ·i:1od1r1c~t!o~ :tnrr.rru?~icc;l ·cn9 t~t "the ArJ!!1 1!: cod.v!nced ~hat any proposals Vhi.cli vould :1nvo1ve mater:al phyo1cal eh~nges · \. ;ln the CCM vh!f.!h ca:nn'ot. _be ·made: :1.n the. ~1e1.d are 1.rr.'ractica1 end 

1Mov1sable, the Arti.y bcl!e1es ·thri. t ae e.n~ter·!m rnc-~cUl·e add!- . t101YB.l: secur!ty 'in Co?nb!ne~ Co~'.!n!ca.tiqns. can eoia~ read:tlir,J" mo:re economicc.~ly, and inoro- prect1-ca;hly te ach1e:ved ."7 ~ore· frt?.guent . . ·changes in -rotors. · ~he A5A the-refo~e pro!'.'Oee$. t!r!FJ a~ n.n int~1r( · aol~ti?n to the p:roh1eiJ.· In eonnP.ctl6tl ~!.th th!~.; ~e;r: ~1st3 · shoul~. 

not be PiJ.t out ·1n advan<re for tt1

5 lori_z .a . .Pt.r1od a~ 13 r..ov the ~n~, · a.nc1. we m,.ght even cons!t!e·r, the !i>oesihili t:r or I!. t'H'~ce da1i:r iMt~o.d of a single ·&1.11y cbS.ngG · ~n s,et'tincs. . Also,. 1 t.. ! s. \ioss~ble t.h"3 -~;r.mlght ~h to co~te~~on 1~s p:rogl"arn·o~ ~'!t~lopinc tl\e attto .. . mf1.tlc. r-otor !Vir.tng. !!!l!le!_;.1lle •. :. Tlus vou11 ra.~11 .... ta,~e rei-r~rlng r:otor::! 

and migHt s~~lify the· Pl9oblern ~or more ~equent tbange or rotors 

. tor. bo~h Navy and A~my ~· . . _ !I . . ., . . . 

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· .b. ·The Al'my reel~ ~t shouli:'I. an etn~1'g@ney-: sr1~e in the p'Zrir · 

rut11.l:e ~k.ing .. volum1nou~ . Ooip.!'1~'ed Commu.'l.1cat!on~ ti: ne~e.ss!', ti~ en~ .. ; 

should .~.,ma1"e at tht,i~ tt;w bt;· an· C.·:>nb~~ 4bout .th~ ~eeutt1 t 1 ' o'! , .thoae cdlil:nm!cations Yith t~e u.e.o~ the OCT(~ th~ SIGABA-fCM could 

be 1sa~d to the Br1t1sq ... W"ov1~e.a· no other ~u1~nb~c nachine . · .t:orE> available f'or the. purpose ~t that t1i:ne.. · ·. · •. • • - . .i .. • --: I .. ·.. . .·: .-· .. .. . . . . ·1 . .· . 

·c." 'F lr.all7, the A!rrir:J. te~s· tMt .. th~ A~ all4 "P.svy shou1a .. · . ' 

jointly, inform the Brit1~h of t~e ,!oreg~i~.~n(t ~eek t~!~ o!'1.'nion 

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