MEMORANOOM BI TIIE DIREOTOR1 NA'I!ONAL SEClJRITY AGEllCY 

tor the 

JOINT CHIEFS OF' STAFF 

on 

REPLACJ!MENT OF THE COMBINED CIPHER MACHIBE I Llerencee1 ' a. J.o~s~ ~~7471 o 

li. J.c.s. 2014/14 

a. J.c.s. 207lJ/21 

. - l. The U .K. Obiets ot Starr have replied (Enclosure to J .c.s. 2074/21) 

to proposal.a made b7 the u.s. Joint Chiets of Staf'.f' (Enclosure "A" to J.c.s. 

2074/14) pertaining to replacement of the exist1.ng Combined Cipher Machine 

{ CCM). The proposals b;y the U .s. Joint Chief a ot Staff were made in light 

or a request b;r the U .t. Chiefs ol Start, dated 4 January 1952 (Enolosure to 

J.c.s. 2074/ll), ~or the u.s. t.o provide equipments (either AFSAM 7 or 

AFSAM 47) on a. tree loim basis tor Commonwealth and NATO use, regardless of 

whether the cryptopr.tnciple was AOOHIS or BRUTUS. The u.1. Chiets or Staff 

now urge •election or the BRU1'JS a;r•tem to replace the CCM in accordance 

with a UK/us agreement., made in September 1950 and approved b7 the U .s. 

Joint Chieta ot Staf'f in Januar;y l95'l., to use this ocyptoprinciple (Enclosure 

•B• to J.c.s. 207417). 

2. The reply to the U ,t. Obie.ts or start contained 1n the enclosure 

atates that although the problem is urgent, this urgency has been lessened 

b7 the u.s. aoti.on in releasing the ECM to the U.K. and is not now sufficient to warrant immediate adoptlon ot BRU'l'US. The repl.7 states that the 

u .s. now .tavors the .AIX>lf.IS Ol")lptoprincipl.e. It recommends that the decision 

on the Cl")'pt.oprinciple to be uaed in the new Combined. Cipher Machine be 

deterred !or at least 120 da;ra pending the outcome of sernoe tests o:r the 

' 

AFSAM 7. Eniphaa1s ia placed in the rep17 on the tact that AOOHIS otters 

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considerable advances in arypto-tecbniquea, nexibili tq or usage• and 

cons1steno7 with u.s. Joint planning. 

3. Separate action will be taken la tar with respect to the question 

ot release of the Hew Combined cryptopr.tnciple to the Union ot South Af'rica 

raised in Enclosure "B" to JCS 2074/2l. (ACT 97). 

TSP SECRET 

Declassified and approved for release by NSA on 01-28-2014 pursuantto E.O. 1352a 

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REF ID:A59509 

I Cr SECRE'r 

4. It is recommended that the dratt memorandum. in the Enclosure be 

forwarded to the RepresentatiTes ot the U .K. Chie!'s of Staff• 

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:ENCLOSURE 

DRAP'1' 

MDK>RANDUM FOR THE REPRESENTATIVES or 1U.E UNITED .KINGOOM CHIEFS OF S'JIAF.F 

Subjecta Replacement of the Combined Cipher Maoh111$ 

1. The U .s.. Joint Ch1e.ts o:t Sta.ft have •tudied the memorandum tram 

the U .K. Chi.eta o:t Starr 1 ACT 96, dated $ December 19$2,, and regret that 

they oannot agree ~~to the proposals in paragraph 6 thereof. 

2. The u.s. Joint Cbiet"s or Stat£ ag:ree as to the urgency o:t reaching 

a pract.1.cable and acoeptable sol.ution to the problem but do not believe 

that the urgency ia such as t.o compel immediate adoption ot BRU1'US, which 

embodies a cr,ptopr.lnciplei the;r no longer :tavor. 

). 'the u .s. Joint Chiera or Staff' are now inclined most tavorabl;r 

toward the adoption or the AOONIS cryptoprinciple, wh1.C1h represents 

important advances in cr,ypto-techniques. They consider that the J6-point 

wired rotors u.aed in AOOHIS otter greater .tlex1b:lli t.r and opportu.ni qr :tor 

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the use or secure cr.yptoprinel..ples than do 26-point rotors. The United 

States haa atandardiozed on a :ta.mily ot developments, including teletJrpe, 

utilizing J6-po1nt rotors. The U .s. Joint Chiete ot Start desire,, there.fore; 

not to project intD the .t\ltu.ru a oryptoprinciple tor Combined am NATO use 

which would be incom.pat'.lble With other United States cryptodevelopments. . In view ot the raot that the United Kingdom is compelled to use a. single 

machine to meet u.1 ... Commonwealth, Com.blned,. and NA'l'O reqUirements, it 

•eems that it would be to the advantage of the U .K. also t.o standard111e 

on a machine capable 0£ using 36-point rotor1. 

4. The U .s. Servicee have already agreed that the AOONIS crypto ... 

pr.tnciple will be adopted at an earl7 date as a basic system .t'or U .s. 

Joint commun1c&t1.on•, it semce ~sts (tield trials) prove the AFS.AM-7 

Jatlef'act.o17 • 

~. Although the U .s. has experienced~ delays in the production 

ot its embodiments or the ADOHIS cryptoprinoiple, one or these embodim.ents, 

the .AFS.AM-71 is now well in production am aervice teats b:y U.S .. Serficea 

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·- ~··_-: -·REF :rn: A59S09-~· _-

TOP SEGFcET 

ot final produc ti.on models will be completed within the next 120 days .. 

The U .s. has already supplied the U .K. with one ot the recentl7 delivered 

pre-product.ton models of the equipment, tor study and tamiliarimatlon1 and 

plans to furnish 10 tD 15 !'in.al production models (prev1ousl7 scheduled 

tor deliveey b7 l Januacy 19$.3) by 1March195.31 for U.K • .t'ield trials. 

\.~ .. /,.., .. - 6. 'It upon completlon 0£ the u.s. 8ertice teats or the AFSAM-7, the 

P~ ( U ,.s. Joint Chj.e.t's of Stat'! drtto~ne tllat the equipment has proTed to qe , 1 + U -- ~ ~ .._~.,.-.~ '}o~fntf.aUI<- J"'-4 ~~~i- . ...-- aceeptable, ~~lliiiiiil& the adoption o:r "18 ADONIS a~I\ ~Oi'US f'. 

/Oi> ~ ~ =-'!fl tor Co11lbined «nd NATO use. ( t. r7.e. t ""' 11 } 

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~ , 7. The U .s. Joint Chiefs o:r Start appreciate the apprehensions o:r 

the British Cbiets of Staf.t that outbreak 0£ hostilities might find the 

Bri ti.sh Senicea inadequately equipped !or aeoure Nattonal,, Combined, or. 

R'ATO comunications. The;r have therefore explored the possibility of 

alla,tng these apprehensions. 

•· In January-, 1950,, the U .s. Joint Chiefs of Staff assured the 

:Sri tish Chiefs of Staff' thay 'they would endeavor, in the event ot an 

em.ergenc7 occurring before the new COM became available,. to prov.Lde the 

U.K. with a limited number of cipher :machines o:C adequate seourit,- to meet 

immediate urgent need.a of highest commam Combined co:nmunications. Rather 

than wait for an emergenc7 the U.S. Chiefs of Staf'f have authorized the 

Direotor ot the National Securl t7 Agency to disclose the ECM primiples to 

appropriate U .K. authori ti.es and with them to plan :tor the 1ntrodu.c~on ot 

available quantities of ECM'a :tor Combined communicatLons. It is under• 

•tood that as a result or recent planning~ the U.K. and# the u.s~ 

1nTolvine: Combi.ned use or the ECM and redistribution or :the CCM;a signiticant 

additional quantity ot CCM•a is now availabJ.e. This action together with 

a recent re'f'ia1on downward or HATO requirements for the CCM indicates that 

the latter can nov be subatant.1.al.17 met. 

b. In order w enable the U • .K. to meet the 1 January l9S!> data 

tor the initiatton of the program tor the replacement ot the Combtned 

Cipher Machine, the u.s. wouJ.d be prepared to make available to the u.K., 

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under arrangements to be determined later,. U .s. AOONIS equipments, at least 

until the U.K. could proT!da £or its own version ot Aro!lIS. 

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8. The u.s. Joint Cbie.ts ot Start, there.tore, "8'\'eftl! that 

he decision e to which cryptoprinciple be adopted in a 

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machine to replace tb;~combined Cipher Machine be deterred. for 120 days, 

until the results or the sen1.ce tests or the Ats.AM-7 hae become known. 

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