• 

IRUQ!ifil(f ot THE PJ!l.$1fiT QO:ABim> CiffiER IACHIO 

l. !o comment l.'nd m~e recomr.midr.tions on mamor ndtim trom the British 

Qrl.efa ot St:'tf {RDC 1/361 dr-.ted ~ ~ember 1949; enclosure to JCS 2(1'/4/1, 

~tod 6 December 1949) on repl!:!.cement ot the present Combined Cipher Machine 

J. lt is concluded that& 

a,.. the beat solution to the problem ie the release to the tl:a.ited 

t!ngdom ot the principles 0£ tho ;yrrent F.().A. 

;a. That complete intercht::.ngs or cr:YFtogtt:phic principles should not 

be &pproved1 but i:he.t ~ limited ~ft"comGnt should bo proposed. 

4,, lt ii; recommended thc.t the 11emorandum in Fnclosure •1° bG tonrr..rdcd 

to the representr.tiYo8 of the British Chi·d's o:t StatrDeclassified and approved for release by NSA on 11-14-2013 pursuant to E.O. 1352e 

en * '&o 0 rrx 

u.-·s. ms ONLY JOP ... IEGRET 

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- DRArr 

&• 'tt. I. 61.ta ef IW:t UT• 00Jld.4etll4 lb.e 1i6potal.t *84e Sa 

DO t./36 ot 6 Dec•b• 1940 ••Halas t.1ltt rt1plao•ct .i iJw pre•u•.t 

--~ea ol:pher •tls.he (OOH). a. two .-~u•t• oontdne4 la ~e:ph 

·f tt -CO 1/M are Ai.1d.ie1ed ~•ia b tUl'll. 

a. IL.ti tr. I. lhl•ta •t •tatl •• aov •f :e.. .,Ulon '1tat \h9 

#ffi!P t.1. Cipher •dhine, .. 8 1 ~a. \eeo•• the eaa'blnel 

alphw 11&\'ihi:a.e, -4. -.ab a ._,_. pnpo-1 to '11at elleo~. !he 

11., t. Ohle:t• ot 1\aft •• llU)le to Mcttp\ lllll1 of 6.e a1 tttrna'tl••• 

f(fJdtted. b ibe .ippe4l:t to DC 1/i6, (par..-~ '). tb.• prlntlJl•• tf \he »1"•••\ ICM azo• 4Son.S.d•H4 \J '7. I. teohn!.oal a:perta 

\o taU"1 ooaap1er.i,- the aecu.rl\J' :jequt....-.•• for ..-td.nel eoa-

_. il. ~-- o••• 

• II. \h :r-.ra ta iitip1e\• la\erohan.c• of dfptoctl;phlc ,rtulple• 

o a tlll.pi'Oeal 1'&.S.1 i'b.e u. •· lb.leY• of tWf ~lfCI"•\ tba \ ..,. &t"e 

ftl.11 ..._'il• h ...,.,, -.ch a JJ.l'tpOHl. !he 'I. t. lh.lcte of ttatf 

•• i 

Nlaottici lmri'tiir \bat .b. ct•l'tain fta1.ta _. latt.rethace la ••ett•tarr. 

Ii 11 th•l"e/ol"• »ftpo•ed ht b.t•rtJIJs.nc• of o~top8J'hlo tdliolpl••• 

a• ftilp1'9da1 ba1l1, \• oonflned '- tn. toilowlac t1el4e f4 

~taatt-a . --- . "'&& • 

(1) ~.J.epriater qafica fo~ pa•e.,. •f b\el'.ticenot 

(2) J.ow ~01i (Hhol" var- f•••e1a) tei.cr¥t• qli\ea 

(s) lleohall.\ ftdp• t•i~e qet•• 

{6) •••.-ologloa'i. q•\•• •• teleetapldo-.& Ml¥hier. 

(&) ..... u .• 11•t••· 

Declassified and approved for release by NSA on 11-19-2013 pursuant to E .0. 1352a 

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REF ID:A2436032 

JOP8EGREF 

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~ to IC$ 'lllf4/-1 vh1oh :re:J..e•• tbt1e an Jt••tblU.U• to:f .Ula.CS. Olplr.•:wa 

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f. IJl Ut~•d».c '\be J"'bl• 1Jt. '1\• lip\ •f "'9 aew ,..,, J"•IC\ed1 f.hl 

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ei1 r;tf a•01181tf )i.q :ra\VA'4 to tbe Ol'lcl»ai JP'OJ>f1Ml •t .. ..,l,14. Oacdoa 

f~&.bc rel••• to th-. •f V... 'W.tlo :pj,1aot.p1•• ttt ~ G. Iii• IOILO a&t'•e4 ._ 

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I••• •t tb• a 'iQ'Ul4 -.o• ll• • att.-r ti rtl..Unc e.. M•t •· 1. _.Ut.• '8 

e•• utton• 

JOl' SECRElI. S. ms ONLY 

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REF ID:A2436032 

I[~ S. FIES MY JOP &EGRET 

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·4. tile -~•diou t=t•~• •cwat• prnhul.T f'h"..-c:l 

a,lbaat the ;1.1,. ot tu .,. ._ •'fO .," T(f.U 'iUU~ ..,,., or -.he late•-& 

~fOiah of th• 'U'Jd.tacl J1Jtcdo•• '.ftie 7•1"0toi- JCJ 1' at. leut .- n*1•tao\ 

to 4Jr7.P\olt'aphie ~i• .. :S.• the pre1ent !Cl., the 1•rotictr 14lJ 1• -~ •• 

!be ts. •• Coaurdoat1o• Intell.1pnct•'• poait10a •uld #Ut'tu 1••• q;.S.mrl; ti. 

Q $hjQ -~• 'bli••• 4temat1'N•• 

4o Di•ad••'bag•• of acctptanee ot the Fi>Po•al.• tor • T•l'(l)tor :BOX ol' • 

1'-roto,.. iell are • t~Uont 

4• l•i\hw- 1• •&1l•bl•· 

_ i• Pro4U.ot1oJl tott• lor ••Chine• tor Uo s. u. 1rill b6 0o1U1iderabl• 

Ud. the tiae d•lq at, l.e•t thr·• (3) :para be.fol"• !u1l ••al• u•• 10 ull be 

poiil.bl•· 

J. _!b.9 "~oiad po\ o:r "tba Ul\itod Iingdoa~t propoa*1 to ett•'i ooaplete 

,bter~-- ot •t7Ptographio priacipl•• iil a reciprooal ~as:l.(I ta ft.ill e.•n:s~daioed 

id.~o.eptabh• 1Jo•'Mr1 -ee:rtatn. liaited :tetert .... i• •••••1 and Mrtaable,. 

·t;ee~r1, iteiUi ,.._quiriuc e.uh-.. '1 pdaat.ple• are U.te4 1a parap&plt S et tbt 

edo•lttt to IOS fflliho "' 

, . .,, 't1l1a tt.WST 1w1· ••n ffol't~ted 1l th the Jta~ ,_..,, S.wri.v -.or eown~ (.AFS.AC >• 

Declassified and approved for release by NSA on 11-19-2013 pursuant to E .0. 1352a 

. . . Rl!9fl! I . . 

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