30 June 1952 

Special Report of AFSAD Ad Hoo Committee on Rsloo.as of CSP 2900 

1., In accordance idth inst.ructions issued by the Chairmru'l, AFSAC 

at the meeting of 20 June 1952 an Ad Hoo Committaa met on 24 June 1952 

to study: 

a. The imp.licatione of paragraph 9d of the Report of tho UK/US 

COMSEC Conference {AFSAC 6J/63) Y!rl.~h recommended tho release 

of Circuit Mercu:ry to NATO. 

b. The question of the release of the CSP 2900 to the me for 

purely Combined use, a.s an intGl':lm. eolut1.on to the replacement 

of the CCMo 

Mmnbere present wre: 

Colonel R. C. Sears, AFSA, C~ 

Colonel J. L. "18aka, AFSS 

CDR R. L. Tqlor, tEN 

Mr. A. W. Small, ASA 

others pressut wex>ei 

~jor E. J. Giese, US.AF 

Major D. T. lbodruff, mAF 

Cmt F. A. Raven, · USNR 

Major o. A. Davia, SigC 

Ml". D. Wol.rand, ASA 

Ltcol H. B. Blacksten, AFSA 

Dr. R. H. Shaw, AFSA 

Mr. C. W. Wernle, AFSA 

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Declassified and approved for release by NSA on 03-07-2014 pursuantto E.O. 1352a 
30 June; 1952 

2. The Ad Hoc Committee considered the implications of releasing 

Circuit Mercury to NATO. It ws observed that Marcury contains crypto= 

principles l!IO similar to too:se of the CSP 2900 that to offer the machine 

to NATO would mean giving a~ these principles Wich the US has stead= 

f'astly retained for its own use in the past.. Howaver it was agreed that 

these cryptoprinciples are no longer known only to the US and it would 

be nothing but a "bead in the sand" attitude to continue to wi1;.hhold 

them from ou;r allies. It was also agreed that the possibility of loss 

of' the equipment to an en~ -would in no va.y further expose US BACCHOO 

communications to c:cyptanalytic attack. The conmliM.ee therefore reCOJl:P 

mends approva..i. of paragraph 9d of the repo1"t, mibject to a comment stating 

that, "In aU cases wherein CI')'pto--=-equipmmrt.a are to be me.de available to 

NATO, cryptoprinciples will not be divulged to NATO prior to actual pro= 

duction and distribution of the equi.:PmSnt". 

3. The Ad Hoc Ccmnittee considered the quastion of the release of 

the CSP 2900 to the UK, for purely Combined use, as an interim eolution 

to the replacement of the CCM. The Ad Hoc CO!illlittea agreed unanimously 

that not ths CSP 2900 but the ECM/SIGABA ~CSP 889~ aoould be released to 

the UK for High Command Combined conm.unications to the extent tbB.t the 

US Services can supply them. If x-e:iplacmnrur!i is to the full aA'"tent that 

High Command Combined systems ere now established, the requirement. will 

be approximately -==-- ECWs. If distribution is limited to Class 7 

holders the requirement will be approximately == ............ machine.a. The 

following points were con5idered in a.rriving at this recommendation: 

2 

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REF ID:A516922 

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30 June 1952 

a. The CCM is completely outmoded and inadequate, particular~ for 

the enciphe:rmant of Combined ru.gh Command traffic. An imm3diate 

repl&cE111ent by e. more adequata m&chine is highly desirable. 

b. The cryptoprinciples employed in CSP 2900/ECM are wll know to 

UK cryptographers. 

c. The US muet be protected against the ability of an anenv, having 

constructed a high-speed analogue for solving e. UX/US machina 0 

to use this analogue to read m BACCHW communications. For 

this raason it ie riot desirable to provide the CSP 2900 in its 

present f'orm to the UK. 

d. A wiring change to the CSP 2900 UO\.Ud be sufficient to protect 

US BACCHUS against the possibility mentioned in (c) s.bove, but 

this ww.d require modification of existing CSP 2900 machines 

mid wuld require US holders to hold tw different machines. 

e. The same degree ot protection ~' be achieved by providing the 

UK with the ECM/SIGABA. Th.are are approximately 2000 of those 

macbinas in existence in the U3 Services in a non«>0perational 

reserve status. Aleo since CSP 2900 baa a suitch which permits 

inte:rcommunice.bility with ECfVSIGABA tbis precludes the necessity 

for US holders to hold two different machines. 

f. The number of CSP 2900ns available to the US vill be reduced by 

the number of EC?1/SIGABA made available in accordance with the 

above, due to the conversion pTOf;l"Blno But in any arrangement 

to provide CSP 2900 type mB.ch:inaa roma roouction in availability 

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REF ID:A516922 

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will roault. The provision of Ecw'SIGABA will involve a 

minimum of such reduction dua to considerations set forth 

in subpara. (d) above. 

4. It is recommended that the conclusions contained herein be 

approved and the matter be referred to AFSA for the preparation of the 

necessary JCS implom.enting directives. 

4 

Re~ R. C. SEARS 

Colonel, lB.AF 

Chairman, .AFSAC 

Ad Hoc Committee 

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