~- --·~ · . e . T oPF se:=e~g,_ . e 

REPOltT TO Tl-D.:. BRITISH Cll:U.FS OF ~TAFli' ii.ND TH:S U.::i CHI~:l o;· ~TAFF 

' 

OF Tl~ UK/U~ cm:a~1uNICA'.fION S~CUltITY CONL''LRENCE 

ON TU~ . RE.PLACl!.l•l,NT OF THl!i CQJI 

JfELD AT \:AtlHIIiOTOJ~, n.c •. CQ?l·~CING .21 SbPTl:flSbR 1950. 

la As agreed by the. British and US Chiefs ot Staff* a 

. UK/US Conference to consider the replacement or the existing .. 

Combined Cypher Machine opened in ~ashington on the 21st September 19508 as a result ot which the Senior British Representative 

recom;.1ends that the 8r1tis~ Chiet~ or Staff accept the offer by 

the {! .. ::i. ·chiefs. of Staff of the ?-rotor BCI·I principle as the 

lone-term solution or the replacement tor the present combined 

cypher ma chine ( CCM) • 

2 o Related. cryptouaphic devices and features were demon• . . 

strated and discussedo Sumrllaries ot the proceedings at the$e 

meetings have been prepared and these are held both by the . . 

Director, Armed Forces Security Agency, Washington, and the 

Secretary8 Cypher Policy Board, Londono This Conference has 

been of unquest~~ned value in the field of Combined Comnuni~ 

cations Securityo 

3o It is recommended: 

· !o That iomediately and on a continuing basis there be 

complete interc})ange or technical details or the devices 

discussed in this Oonf'erenceo This should include technicai 

visi'tso 

* us· Reference: JCS 2074/2 - 27. December 19490. 

British lte:ference: COS(W)831 ~ 26 July 1950. 

eclassifi ed and a NSA on 05-20-2014 ursuantto E.O. 1352 

TOP S.ECRE·T 
"! . REF ID:A67201 eroP, SECRET • 

,20 That there be annual conferences on this subject 

for the next four years, to be held alternately in ·London 

and in l!ashingto~ .. the r:(rst of these to take place in 

London in approximately nine months timeo ~hese conf'erences . . . . 

.IQ 

should, be concurrent with conferences for the reciprocal /PL 86 _ 36150· use 3605 

exchange or cryptographic. inf ormation·o 

.2,o That the subject of Combill:ed requirements for 

general point~to-point on-line enctjrption be introduced 

at the next Con£erenceo 

4o 'rhe general recommendations in paragraph .3 above together 

with· the detailed recommendatio11s of. the/ conterenc e which are 

attached as Appendix A to this report are submitted for .a~roval 

by the British and U .so Chiefs or Staff o 

Chafrman, U .I<. De;Legatlon · 

·at washingtort 9 n.c. 

27 October 1950 

... 2 ... 

EAftL Eu~· .$TOrl:d 

liear Admiral, U.So Navy Cha1rman9 u.s. Delegation 

TOP SECRET 
! 

APPENDIX A 

DETAILED RECOMMENDATIONS· 

Replacement of the.e~istlns COM 

(a) That the ~ryptographic principles ot _the ?-rotor BOM 

'. 

(cr7ptosystem BRUTUS) be adopted as a replacement ror the COM 

in combined communioationso 

(b) That except by mutual agreement 9 d1solosure ot the 

-BRUTUS principle be · 11m1 ted to the U oS o and to the nations ct 

the British Conim.o~wealth; and that t·he .U~Ko and the UoS. agree 

: ' 

to not1ty 11ach other when any issue ot a comblned BRUTUS system -ci. 

is· made to another nationo 

(c) That the target date tor tull implementation ot 

BHUTUS be set as l January 1955, or sooner if-oiroumstances 

permit 9 and that limited 1ntroduot1on8 where a small number . . . . 

ot machines would be involved, should be im.plemented ·at the 

earliest practicable dateo 

(d) That 1nsorar as practicable rotors ot Uos~ and .Bri~ 

tish versions or the BRtnUS_oryptosystem ~ pb,fsically and 

cryptographically !nterdhangeable and that to this end the 

British should ad~pt one or more of the sizes to be used by 

the U.,So Furt-b.er~ that all datap manutaotur1ng51 and wiring 

details be furnished to the British for this purpoaeo 

(e) That the British and Uo-So make ;l.ndependent security 

~tud!es ot BRUTUS9 including the tollowin6 items: 

APPENDIX A 

TOP S·ECRET 
".! . eTOM~€tt211n e 

. ( l) ·.Possible changes in st~pping order~ ' • • I ' 

. (~) l'otoh. patterns for stepping ·control.~ 

()) . Type ot roto:v.- wiring (.interval 11 random1' or 

oomposite).., 

(4) ~reparation or key list&o 

(5) Indicator procedure~ 

(6) Restrictions on operational use of machine 

for security reasonso 

(7) .And similar technical matt.era~ :-

Further~ upon completion of' these studies _tb.a·_UoSv and ~he ' 

u ~.K 9 exchange technical papers through es ta bl1 ahed channels .•. 

(t) That th~ British and u~so prepare and exchange · . . 

separate papers tor purpose ot reaching ,greements- on operating 

instructions., maintenance instructions, . cr,ypto~,securi ty. pre- .. 

cautions, and o.ther procedural matterso 

(g) That models (when availabJl.e) 11 drawings-a epecifications 1 •. 

. and op~rating 1nst:ruotion.s (where necessary) · ot. the f'ollowinr, 

equipments be iuade avall.able to the British: 

BCM .(CSP 4800) 

"PCM" (CSP. 4700) s,nd "PCM" typo rotor 

Tape Reader (AFs.alil 12· or CSP 5100) 

CSP 5000 Offoline automatic equipment . . . . . 

ENG-)08 Translator for BCM. (CSP 4800) 

Rotor refine.'llente f'cr Mark I ()") , . Ma:rk II 

( 3.i'·'} ., and Mark Ill .< 2-I") . rotors 

.AN/GGA-1 (Instructions only) 

APP:sNDIX A 

TOP .SECRET 
A . REF ID:A67201. .d;.;:/o.,,o· 

: 1-0P SECRET. - °}-~ ,~~ 

Parts 8lld drawillgs tor the naw 'l'YPBiC adapt'!]. ~· · / · ~..,_ y 

. -~~L . '!:r 

Temporarz Improvement ~o the Eltistins · oem ~ ~ d · 

(a) That ~there ~old be iss11ed 20 :roto~ _v . -~-

to tha sat for aaob existing COlt i~ lie~ of present number -~ 

@f ll.~Oo Tillis is ts- b'icome ajDfsotivt» as ,soc.n as ·pre.ct1a~blc,~~~l~\) ~ -~ ~t)petpS~\1>~""'~ '"-~·· . ,.·. ·- .. .r. 

Key !ete~,~ould tie so l!_l'eparsd that no ~otcr will eve~ be · · \'IP~~--~ {lJXA . . 

sfteotive c~_twe &Qcceasiwe daysD within the siame ke1 l~ste 

tcr sa@h cryptccaamiel 9 eo as to pel"Ddt e~~tiDg op two bas• 

k6te for two su.cces~ive days from:a single set of 20 rotors 

th~a obvlatilllg ths neSd for dupli~ate sets or rotorso ~ 

will result 1n a stll9stenti@d 1ac.J'eaee ia.the 1UJJP11.1~ pt rc~o~a \ . . 

tu bi fabi"loated WiCex prese~iaueot I. 

· ( b) 'lhat removable t.ires will bo i.atrodaaced as soon ae . . . 

practioabloo · 

(c) That :matters such as the :&'ate ct superseee:lon and 

speoit!o time·& elf suparsess1on be left to established ageinoies 

oha~ged wi~h such mattereq 

Iv : :- ·, ' 

(d» That the u.s. make a~ailabl& to the B•i-itislt the tools 

and dies.tor Malf'k I rotors (tor old TYPEX Admpter) ... 

(e) That the U.S. make available to tb.e·British·the tools 

··and ch-awing~ ot the old m>&X adapter 9 together w1 th drawing~ 

ot tine new -design of 'l'.YP~ adapter ~otors with tires~ 

APPENDIX A . ; 

TOP SECRET 

- --·---------- - - - -
! flF 0fJRBJ[~=Ftr?f01 • 

~2!1s1on ot combined working between British and UoSo 

crypto machines employing th! BRUTUS technigue and. providins teleprinter tacilitieso 

(a) That the Third Report of the Sub=Comm!ttee appoln.ted 

to investigate this aspect be made available to the . . 

UK/US. JCEC. with the request thatp as a matter ot 

urcency 9 discussion be opened on what Teleprinter 

faoilities should be prav1ded in new ·ort-11.ne com.- . 

bin~d Cypher Machines wh.ich permit., automati~ encryp ... 

tion and decryption in page tormo 

(b) That the Br1tish9 as a ma_tter ot urgency 9 give con ... 

siceration to the UoSo proposal that bigramm.ing .and 

functional signals tor British machines employing the 

BRUTUS arypto technique should be achieved by the use 

ot the tollowing primary characters: 

I1r1mary To Be 

Character l!'unotion Linked to 

K Bi gram D 

J Figure Shift 'Y 

v Letter Sh1tt (Nothing) 

z Space x 

O/R Carriage 0 

Return 

L/F Line Feed G 

6 APPENDIX A 

1·9p SE:RET 
(c) That the UoSo consider the possibility ot pro-: 

v1ding tull_Teleprin~er facilities in tut.:ire 

machines employing the !JRUTUS crypt~· teohn1~ue, 

by utilizing. the Blgram tunction 1no~uded in 

the design o~ the. British "PDDRAGON".o 

"(d) That since provlsion has .been made in the British 

PENDRAGON tor "L1he Feed"· an_d "Carriage. Return" 

signals to be generated Where re~uired OD deotpber-. . . i : . . . 

ment bf 8a1tabl~ oount1ns·meohan1$msll the British 

should give cons1dera~1on to abandoning B1gramm1ng . . 

and_ accepting the loss ot two iawer case o~raoters 

(J and Z) and th~es upjer oaae characters (upper case 

· · J 9 11pper. case .z.t and upper ·case V) ~e is ~t J>resent . . 

contemplated 1n UoSo deslgn., 

(e) That interohange ct vi.ewe in particular on recommendations (b); (C) p llDd (d") &b0V8 be OODtiDU&do 

7 APPENDIX A 

"'FOP SECRET 
Replacement rcr the present Combined Cypher Ma~bine 

lo '"e agreed by the British and us Chief's ·or Start* · a Bri= 

tieh/Us Conference to consider the replacement of the exist= 

1ng Combined Cypher MaGhine opened in Washington on tbe 21st 

September 1950 ~ u o.. /"2-~~ ~ ~k te...a_ (Y',., 0-· rf'') .-~~ ...h~ )Ul.C-c-- -~(, 

2<;> Many relat~d oryptographio devioea and features were de= 

monstratad and discussed~ Summaries of the proceedings at 

these meetings have been prepared and these are.held both by 

the DirectorP Armed Forces Security Agency~ Washingtonr and 

the Secretary 9 Cypher Policy Boardi) London,, 

~l In our estimation this Conference has ~een .or outstanding 

,,sJJ}1;;~~ommwUcati~ 3, ~l..J:Gw:Nlg-ge~mmrum~a.tio~a:. 

(a) ~mmediately and on a continuing basis there 

be eomplet~i~c~i~al details of 

the dev1C'3B · discusae"p\ This should include tech= 

nice.]. visits,, 

(bl ~ere.be annual oonterenoes on this subJ11ct 

for the next four years 9 to be held alternately 

in London and in Washingtonp the f 1rat of these 

to take place in London in approximately nine 

months timeo 

• US Reference: JCS 2074/2 ':" 27 Deoember 19490 

British Reference: COS· (W) 8)1 - 25 August 19500 

TOP SECRET 
.... REF ID:A672,. 

TOP SECRE · 

(o) ~~he subject or Combined requirements tor 

g~neral point to point on=line encrYPtion be 

introduced at the next Conferenceo 

~0 0 T~~t1ons in paragraph) above together with the 

~·-t...#-~~~......_~,~~ 

detailed~ c~e*a&J:e:B8 ot tfie oon~er~nos ·which are attached as 

Appendix#!eto this repo,rt are subm!tted wttfr'thlf""re·c·ommemlat!-on · ...- -·~IVV· .. · · tiiert-t1l~ - ~sad- by t.he Br1 tish and U o Sa Chiefs of' sta:t'f o 

I\. 

TOP SECRET 
.. APPENDIX A 

l"Rc- l{t~IC,\\,.. RECOMMENDATIONS 

Replacement of the existing COM 

(a) Tlnat ~. T' ~. . the o:ryptograph1o prinoiplee 

of· the ?=rotor 

. . 

BCM .\Jt:=-0 as a 

.. 

replacement 

P-6; ~~~~~~) tor the -COM in ~ 

combined 

~ 

~ 

communications., 

(b)' That except by mutual agreement 9 disclosure or the 

7-rotor BCM principl~ be limited to the UoSo and to the British Commonwealth9 and that the British agree to notify the 

UoSo auth·orities when any issue of a oombined ?=rotor BCM . 

system is made to a nation of the British Commonwealtho ~ 

. (c) That the target date for full implementation ot the 

?c:.rotor BCM be set as l January 1955 9. or sooner 11' oircwn= 

stances permitr- and that limited 1ntrcduot1on" where a small 

number of' machines would be 1nvolved9 should be_implem.ented 

at the earliest practicable dateo · · 

. ~\rha°(~ ~ U;,So ~nd British versions or &'~~~~~fi . the ~~ ~e physically and cryptographically inter- , , i . ~~t.!)f./~' cha~geable and that to this-~nd the Br1tis~ should·~ [&QJ~ ~ 

.to.a:ne_e.iiiNlow us~-=rH>IrG" Further 11 that all data 11 ty~~ 

:--· . . ~ t4 tJ) .. manufactur1ng9 and wiring details be furnished to the Br!- <:) . · 

tish tor this purposeo 

(e} That the British and UoSo make independent security ,0-.~ studies -oy the ?=rotor BOM 0 including the following items: 

(l} · Possible changes in stepping ordero 

APPENDIX A 
(2) Notch patterns for stepping oontrolo 

()) Type of rotor wiring (1nt~rval 9 random9 or 

composite)" 

(4) Preparation of key listsa 

(S) . Indicator prooedureo 

(6) Restriotions on operational use ot machine 

for security reascnso 

(7) And similar teohnio~l matterso_ 

Further" upon completion ot these studies the Uo.Bo and the U .. Ko 

exchange technical papers through established ohannelso 

Ct~ That the British and u.so prepare and exchange 

separate papers f'or purpose ot reaohing agreemell'lts on operating 

instructions~, maintenance .1nstruot1ons 9 orypto ... securi ty pre'"" 

oa~tiona~ and other procedural mattersQ 

.: :·-- _.(g) That models (when available) a drawings~ speo1t1oations 9 

_and<operating instructions (where necessary) of the following 

equipments be made availabJl.e to the British: 

BCM -(CSP 4800) • 

"PCM" (CSP 4700) and tvpm.t•v type rotor 

Tape Reader (AFSAl/I 12 or CSP 5100) 

CSP 5000 Oft-line automatic equipment 

' 

ENG-)08 Translator tor BCM (CSP 4800) 

frotor refinements tor Mark I ()")t Mark II 

()t") 9 and Mark III ~2i"> rotors 

AN/GGA""l (Instructions only~ 

4 _ APPIJ:NilIX A 

TOP S_ECRET 
,, 

- REF ID:A672. 

TOP SECRET 

Parts and d~aw!ngs for the new TYPEX adaptor 

.Temporary Improvement to the -.H:xistins CCM 

· (a) That ~k~~ould be 1ssu~d 20 rotors 

to the set tor each COM in lieu or present number ot lOo . 

-~beeome-~ta_ctt .. v.e..w~-t~t'b:e-next-·t~sae:o~ew"'"l"'O't'Or's~ 

Key lists should be so prepared that no rotor will ever be 

:effective on two suooees1ve daysp within the same key lists 

t,or each cryptoohannolil so as ·to permit setting up two· baskets for two·suocessive days from a single set ot 20 rotors 

·thus obviating the need. for duplicate Qets ot rotors~~ 

~~Jrcse~ _:I n .. nO-SUbatan.t-1aJL..;1nor~e number o.t rotors -, 

~lftirlr unaer=present~~ 

· ( b) That removable tires will be introduced as soon as 

(c) ' That matters such as the rate of superseasion and 

specific times of supersession be left to estabiished agencies 

charged with such .matters" 

(d) That the UoSo make available to the British the to.ols 

and -dies tor 'Mark I rotors (tor old 'l'Yl'il Adapter)"· 

~e) That the UoSo make available to the British the tools 

and drawings ot the old TYPWC adapter 9 together with drawings 

ot the new design of TYPEX adapter rotors with tires.<) . 

APPENDIX A 

ro·p SECRET 
Provision of combined working between British and UoSo 

~ypto machines employing the 7.,,.rotor BoCoMo technique and 

providing teleprinter tac111tles~ 

(a) That the Third Report ot the Sub~Committee appointed 

.to investigate.this aspeat be.,made available.to the 

UK/Us JCEC with the request that 9 as ··a matter ot 

urgency discussion be opened on what Teleprinter 

faailities should be provided in new Off-line ComQ 

bined Cypher Machines which permit automatic enorp= 

t1on and decryption in page formo 

(b) That the British as a matter ot urgenoy give oon= 

s1deration to the UoSo proposal that b!gramm1ng and 

functional signals tor British machines employing the 

(o) 

?=rotor BoCoMo crypto technique should be ac~iaved by 

the use of the following primary characters: 

Primary To Be 

Character Function Linked to 

K Bi gram D 

J Figure Shift y 

v Letter Shitt 

z Space x 

C/R Carriage c 

Return 

L/F Line Feed G 

That the UoSo as a· matter of urgenoy consider the 

possibility of providing full. Teleprinter facilities 

in future maoh1nea employing the ?=rotor BgCoMo 

crypto technique I\. by ut111z1·ng the Bigram function. ~ . . 

TOP SECRET 6 . APP~DIX A 
• 

included 1n the design ot the British ":PENDIU\GON" o 

· ·(d) ~hat since provision has been made in tha British 

P!ml>RAGON tor."L1ne Feed" and "Carriage Return" 

·sign&ls to be generated where required .on decypherment by suitable counting ~eohan181118 9 the British 

should give consideration to abandoning B1~ramm1~g 

and accepting the loss or two lower aas.e oh.araoters 

(J and Z) and three upper case characters (upper oase 

l~ upper case Zp and upper case V) as is at present 

contemplated in UoSo design~ 

(e) That interchange ot v19\vs in part1oular on recommendations (c)p (d)p and (e) above be continued 

through existing channelso 

7 APPENDIX A 

TOP SECRET