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COi~INi!D CIPHER MACHINE 

Minutes of a Meeting Held 23 .l!'e~J 1947 

PRFSElIT 

u. s. Ns.yy u. s. Army U, K, 

Capt, Smith, Chmn Mr. Friedman Col. r.:arr-J ohnson 

Capt, Safford Dr. Kull back Capt, Wilson 

Cdr, Seiler Dr, Sinkov 2.1r. P~ndered 

Cdr, Hargreaves !A.r. 3arlow "T 

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Captain Smit..11. opened the r.to:?etin5 by readillg the_ .. jollit United States 

report prepared in connection ··ri"th !t;t-2o, (Inclos1.JI'e 1) ·.:he reading of this 

paper was followed by a brief discussion of t~1e United States position, Mr, 

?riedrnan expr~ssed the aFpreciation of the Unitad States me~bers for the 

!'rankness and unqualified !!'.P-nner wit..'1. w~ich ~he British had submitted their 

ideas for consideration a."ld added that he felt that nothing has contributed 

more to the continuance a:' amic~bJ.e relations in =:he cryptographic coordination between ·~he t~9 countries. He pointed out as an addition to the joint 

paper that the advantabe ot' unenciphered indicators is of d.efinite importance, 

The United States services are considering simplified handling ot indicator 

systems with particul.ar emphasis on proc9d.ures o;1hich ~Tould be carried out 

independently of the cipher machines themselves, Captain Smith felt that 

the ma.china should be used ror the generation of indicators rathnr than any 

auxiliary. equipment. Mr, Friedman went on to state -:.hat there would be 

considerab1e difficulty in attempting to justify such an engineering deveiop.. 

ment as the construction of R!rt-26 in view of the fact that the CCM is available 

in large numbers .!:i.nd that so much emphasis in United States plenning is being 

placed o~ low echelon communications. 

Captain Saf'f'ord ror Navy indicated that a similar need for low echelon 

-development had been indicated i.~ their service; in particular, a request 

had been received from the Marines for a new low echelon device. Though 

the Marines indicated satisfaction with t.he Hagelin, they had been advised 

"that the security of the Hagelin was not considered sufficiently great, and 

in addition they would like a keyboard. attach.'D.ent to their cipher ma.chine:,. 

Captain Smith ma.de the poi..~t that :although the British a;e committed'·to 

the supersesaion of the Typex, the United States is not committed to a replacement program, He susgested the possibility of agreeine; to a modii'ication of ~e CCM. that could be under+..a.ken in our laboratories and expressed the hope 

that an acceptable degree of security could thus be achieved. 

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Declassified and approved for release by NSA on 09-19-2013 pursuantto E .0. 1352a 

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• Captain Nilson in answer to these remarks made the !ollowing points ~ith regard to the scrapping of the Typex. T"nat the prime movers· in that 

co'!'l?'sction had been +..he 9ecurity people. He sain tr.at the machine could 

be modified and improved up to the level o: the improved CCU, but even that 

increase in security was considered insuffici~nt. Jrom a practical standpoint the 1:18.chine had been found reliable. It had stood up under a tremendous amount or use and a woef'uJ.ly inadeqUB:. te program 01"' maintenance. It 

had carried all or the British raw trai"fic with·the special advantage of 

bein6 able to handle both upper and lower case char~cters. 

The possibility was then discussed of a contL~ued investigation of the 

RM-26 ~Tith a view toward makin:=; it intercommunicable ·sith the CCM. '!'he 

development could t3.ke the direction o.r providing for a special use of the 

ma.chine. Fo!" example some combined coramunica. tions were certair.J.y needed to 

implement the existing authority for collaboration in sie;naJ. :!.ntelliJence. 

If the machine proved successful for such purposes, a Combined use could later 

be worked out, and that perhaps i7ould t~nd tmvards ~~r.e desirability of collabo-

~ation on Combine~ systems in general. 

Captain "'Tilson indicated. -~-hat continued investieaticn by the British 

would include the idea of providing t~letype facilities ~s -vell as including 

a machine to \York ·flith the i.mproved CC~!. It was aJ:-~reciated, hol'l'ever, tr.at 

the quest.ion had to be pr~s-ent·9d to high.er aut.ilorities fer approval. Captain 

Smit."1 raised th.e point +.hat a.::: yet the iJnit~ States sei-vice:i have not received orders to proceed on o. prograr.i i:i? collaboratio!?. in the dov<!lcprnent of 

a Combined machine. 

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~.!r. J'riedman then indicated tr..e.t a good starting point would be the 

es"ta:blishment or a set or Comb-ln'9d rules for security. This led to a discussion 

of the differences between "':.he regulations o! the t;:;o 210.tions. Frol!l the point o£ view of the United States, signal intelligence considerations weig.."1 equally 

witli security considerations. The British policy does 1101~ differ i"roni this 

in peacetime, but in wartime the British tend to place more 1Jmphasis on opera- tio~l security. The two attitudes require the str1.1<:ing of a balance. It 

was 'suggested ~t this point that the British mig."1t study in thia connection 

the Navy publication RPS-48 and the corresponding .Army publication A..~ 380~5 

and draw up a set of rules which could be presented. to the Combined Communications Board. The United States 'Rould similarly prepare a proposed set or 

rules. 

At this point Captain "?'Tilson stressed the fact that the security of the 

present CCM is unsatisfactory a.~d that any major change contemplated waald 

take time. Could we consider an immediate change to changeable cam contours? 

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Captain Smith indicated that arrangements are being made ror a test or the 

. improved CCM with chaneP.abl.e cam contours. Information in this connection 

will be available in about two mont.b.s and a complete statement or the results 

·will be provided ·to the British. A further point. was made by Commander 

SeilAr that developments are also underway on the provision of a special 

rotor wiring machine which will be ready berore long ~nd will. greatl;y simplify 

the rewiring or rotors. Mr. Friedman suggested the consideration of increasing the number of rotors in a complement, .but the Committee agreed that it 

was preferable to provide tor more .frequent phange in the present set 0£ ten 

rotors as a whole rather than add more rotors to the present complement with 

. ·· -~f!~~uent change. 

Captain Wilson presented a state~ent of the cryptographic security requirements desired in a new COM. Briefly sta.t.ed they are: 

1. Re-encipherraent ~r messages to be possible without the need or 

paraphrasing. 

2. E:limination of bi3ection, burying and padding. 

3. System must be· immune against c:t'ibs. 

4.. lfo cJ;Langes of setting of varia~e elements to be required within a 

· message. 1!i • • 

5;:. Ind..i!!&tor system to be as simpl~ as practicable. 

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