''" .. 

Pit C-MC SW-3 .. 6 

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REF ID:A522793 

OOP SECRE11 

24 

USCIB: 14/112 

APPENDED DOCUMENT~ CUNIAIN 

CODE WORD MATERIAL 

8 January 1951 

Mlt.t«>RANmM FOR THE 1~\IBERS OF USCIB: 

Subject: Security of Foreign Communications~ 

lo The attached letter on the above subJect is forwarded at the direction of the Chairman, 

lJSCIBo 

2o This subject will be discussed as an 

ite:11 of the agenda for the Fifty-ninth Meet1nr.a 12 

January 19510 

USCIB: 14/112 APPtNUED DOCUMtNrs CUNlAIN 

CODE WORD MATERIAL 

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Declassified and approved for release by NSA on 06-11-2014 pursuant to E.O. 1352e 
Chai:rmanri 

London 

12th December~ 1950 

SB/783 

EO 3.3(h)(2) 

PL 86-36/50 USC 3605 

United States Communioat1on Intelligen!Je Boardr 

====~--=---------=----=----------===--~-=--------

Subject: THE INSECURIT!.-Q=E.J'L.. __________ _. 

In accordance with the U o S._, - Br! ti sh Communication Intel.li= 

gence Agreemantr LaS,,LBo wishes to raise with U.,S,,G_pioB? t.he 

problem of the insecurity of French cyphers as a matter at'f'~et1ng 

Third Parties to the Agreement (paragraph 5)~ 

2 ., This problem was the subject of a11 exchange or views between 

the American and British 8ecretariea of' State tor Foreign Af:t"airs 

in 19480 At that time Mr~ Bevin said thatc in view of the gravity 

of the issues at stake, he thou:t that th8 French/ should be informed w1 th I t and this 1n · sp1 te 

ot objections rrom his expert a visers" Mrc. Marshall 9 however\v 

replied that the National Security Council was unable to aocept the 

British proposalso 

3o It is the view ot LoSoioB., that oiroumstances now exist which 

require a re-examination of this problem,, In the first plaoeti though British cyphers have been 0 or are in course of being~ pro~ 

vided to France and other countries tor the transmission of inter= 

national traffic dealing with Western U;nion and NoAoTvOo a:tfa1rsP 

the security of French teleeram.s on related or national subjects is still seriously inadequateo Secondly& the trend or international 

events makes any French oryptographio weakness increasingly inimical 

to U.,S" and British interests" Finally~ it is important that the 

Comint agenoies should reach agreement now about the action required 

so that it may be taken at the first appropriate moment~ 

4~ L?S~I~Bo is ot the opinion that French oypher security can only 

be adequately improved by the French w1dertak1ng a oomplete reorgani~ 

sation of their arrangements and acoaptj.ng outside teohnioal advice,; 

It will be ditf'icult to persuade the Fri\"moh that these radical 

5,, It is proposed that we should firm~ approach the French at the 

highest level and inform them~ 

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(c) that 9 should they not believe thisv we are prepared to 

demonstrate it to their experts provided they will agree~ 

(1) completely to overhaul their cypher arrangem.enta 9 

.( 11) to accept the appointment of British and/or U o s.,, 

experts to assist themo 

/ 

Only when all arrangements for the a 

com leted would we roceed to ther---;;;""'"""";..;;;..;;;;.;;;;..;;;~-=----"-""'-""-=;;._~------------.. ........... --....____, 

1" L.,SoioBo therefore seeks the concurrence of U~SoColoB.,, to the 

following proposals: EO 3.3(h)(2) 

PL 86-36/50 USC 3605 

(a) that there should be agreement in principle' that an 

approach to the French on the lines suggested/above should be made at an appropriate time; 

(b) 

--

c) that to etf'eot this oollaboration9 AaF~S:.Ao and G..,CoHoQ." \ should independently work out plans which would be 

, brought tpgether at a conference to be held early in i 1951; 

~t; once the combined technical plen has been agreed; rurther consideration should be given to deciding when9 how and by whom the plan should be implementedo -- 8~ In order to save time and in the hope or UoSoColoBo agreement 

to these proposals 0 the technical research required for ?(c) above 

has already been set in motion at GoC-~HoQ." 

/s/ I PL 86-36/50 usc 3605 

CfialrmanD 

SB/78) London Signal Intelligence Boardc 

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