BRIEF.INa SHEET FOR 'DIE CHAillWl, JOINT CHI&~ OF STAFF 

JOINT CHIEFS OF STAFF MEETING, 0915, WEDNESDAY 

28 MAY 1952 

AGENDA. IT.HM NUMBER .3 

J .. c .. s .. 21Y14/14 

SUBJlOO'l': SECURI'l'I OF THE COMBINED CIPHER .MACHINE 

BA.CKGROUND: 

l... The cryptographic security- ot the Com.bin.eel Cipher Machine (CCM) has been ot considerabl.e cancem to U.S. and U.K. ceyptanalysts tar some time, and several measures to improve 

its securit;y have been taken, including replacement by a new cryptographic principle. ~ 

replacement target date ot 1 Januaey 1955, or sooner, has been ag1seed. 

2. The U.K. Chiets 0£ Stat£ have proposed (&iclosure to J.c.s. 2!J74/ll) that the ultimate 

replacement of the CCM be accomplished by the provision, b.v the U .s., ot the cipher machines 

.APSAM 7 or AFSAM 47 to the Brit.ish Commonweal.th and NATO nations on a tree loan basis. Thq 

state that the 7-rotor principle, which was accepted as a rep1acement tor the CCM, in the 

form of an adaptor, for their TIP:U machine 'td.ll not be read1' 'betore l Januar,y 195.5, and that 

no euitabl.e new British machine is sutticientl,y e.dvanced in development to permit production 

within the next tour years. The U .K. Chiefs or Staff point out. turther that the 7--rotor 

adaptor they have under deve1opm.ent will be suitab.le tor use onlJ' with the 'fiPEX• which doos 

not exist in sutf'icient quanUties to meet their share or equipnents which will be necessal'Y' 

for llA.'l"O communications. The CCM' s now used by NA.TO a.re provided in approximately' equal 

quantities b;y the U.S. and the U.K. 

CURRENT REPORT: 

J. The di~att mmnorandum to the lh-itish Chief's ot Stait informs them ot the daten on 

which the requested eqgipments cen be made avail.able for service tests in the U .. .K.,, but asks 

tor additional intormation on requirements ot Commonwealth Nations bdore answering the request 

that the equipment be prowided in quantity- on a tree loan basis. A plan ot e.cticn ia proposed 

to t.he British Chiefs ot Start for further consideration of this matter because it will depend• 

in part,, <'>n the outcome ot the service tests which both the U.S. and the U.K. will. conduct .. Upon completion or securit;r studies and service tests,, the U.S. 1l1ll recxnm.end to the U.K. 

the eqμipment or equi.pnents to be used tor CClillbined and NA'l'O communications, thus avoiding 

the likelihood that tinal choice ot u .. s .. equipnents 11."0Uld be governed. too great]J· b7 mr 

selection the U.K. mi.gh.t make after service testing the two equipnent.s. The ~proposes 

then t.hat the economic and time £actors involved be explored trom the viewpoint ot either 

complete replacement. b.y naw machines or whether partial use can be made or adaptars to present 

eq)li.pments. 

' 4. It. is furl;her suggested to the British Chiefp ot Staff' that. they consider the .teasibilit,- of producing in the U.K. either ot the two equipnents,, both of which have been examined 

bT U.K. e113ineers tram a pNduction viewpoint. 

RECOMMENDATION: 

s. It is recommended that J.c.s. 2<Yf4/14 be approved. 

o CAII?m 

ral US A.rm;v' 

ces Seeur.lty- Agency 

Briefing Sheet prepared by Mr. James H. Dougl.aa 

Ext.. 6o421 

Plans and Policy Division 

CC: General Bradley (3) 

Director,, Joint Start (2) 

Deputy Director. Arm;y 

Deput7 Director, Nav;y 

DeputJ" D1rector,, Air Force Consul.tant~s:aaz -4[' 

TOP SECRET 

(1) orr. ot a&D (1) 

(1) Ott. or OO:VJSF.C (1) 

(l) Adjutant General ~ (3) 

(l) Plans & Policy Div. (2) 

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