.*REF ID:A71B68 

- , f ~ -\J-' ,..,.. ·r> ""1~tJ-..H--:- f°'fo·6W -

~i I..• Q, Q $,I. i ,_,.,f t·~M 'k-IJir. i.iJ.t I ~ 

~-. llj'-?b 
• •• .IOINT aCURITY CONTR01? oa;~~ '~J: '.' ~ . ~.~ ! .. •• ,.· .... ' . ~ .,. ... . 

.. 11~ OL il!/.t;-~ WMHINGTON. D. c. Dll':.• ••• f • . . • I 

I .. . 

·,~_.-5 . : 

,. 

. . lmil>lWmJK FOR THE· CHii1' OF b'TJ."t F: 

Subject: Security oi' ti.~":1.~l .::v:..t~.UlliCi::.ttorir .• 

1. Consid.ers.ble evidence he.a been a:~.ssed in .the .,a.st 10 · daJ'• 

indicating tlu.t Zte.te Deu&i·t.: . ..ent cuc~es ~1~\"t:' cert.i.d.nl;y i.i•.:e:-n jeopudized. 

Ec?ual.lJ" strcne evillence inr:icrttE"s the ~>r·"lbr.b!lity that :nilitarJ' intelligence cocies, at lea.st those in effect prlo::- to ~.::arch ~. have been 

caaprcx11lsed. It is not. improbable that the co~es snd ciphers now 

being used qy thRter CODlllE.n~ers i:mvt> liii:.et:ise b~ ~ c~tied. 

2. The St.ate Dtt Jart.m.e:it has befln ::aymrized of the ait..uation inaotar &S their Code is concemed. ~·mat. E ction \'.ill be taken IJ.t" the 

state Depari.ment in regard to their. own codes e.;•parent:q has not 7et 

been determined. The. mllit817 atta.che cof.es ..-:ere ch&.nged iarch 11 and 

tbis wlll give us a temporary me~sure of security. 

' 3. The aituatiaa .insofar as cOz:11?12nce!9s of eictive t~~eaters is 

cancemecl is auf'f.icientq aerious to 1mr~~;11t iminE:·ditri.e :i..nd r&r.:ical 

actica. ·In the past the \far Department for t. vc.riety of reasons, 

nme ot Jlhich are either aouad or def'ensible, hrs stuck to the laz.r 

man1 a wq_ ot h&ringJ!IL code with a 1dde distrlbution in use, 't.i.th 

the resalt "that it the code is compromised in on(·~ place 1 then eve17 

m~s&aBe trm. 81Q' place· in the worid runs the risk of being intercepted 

and ~. It is Yital the.t we now initie.te e. 3:.'Sttm l~ich Y.'il.l !Jrc>-

um. lat.val cammnicat.icn bet.treP.n thtr~tP.r cCll!tn:• ic:t: .. ·s and at. the same 

time w have Terliical qatan.s of en . .:1un ~ t:''tioo. ili 1iif1"Prent c-Jc!es 

between \heater camnendera en~ •. ashi:·rt.on r:c t.~;.Et if .:. code be ~ 

~sed in me theater it will not &.~:feet. c:. , :r&..t.io~u• in c:.;1other. 

Thia sJBt-, cou.plcd with·· tre•:uent c:,ange in cocit=s E.hd cinhcra, 

shoalld af'tord a :reascna'bl.e .deeree of securit;r. . 

4. It is recClllllleilded tbE.t: 

.!• Imediate ateps ·be t~i-:en to ?rovice six ee;>are.te and. 

di.atinct &yllt.ema ot coc~es L"ld ciphers; t.~.ct.6 sb:. sylltems to be 

pit Sn effect at the eerliest possible: date Es follm:s: 

·-

II' ,.... ••• •• . • • .., .... 

4 .,. 

• 

) rift' ,..,....: .·. 

.. · 

.. 

-" 
... 

••• .• I r • • 

f' ~~ !~fA 71f6• . . . , . 

'.~\ .,.. . -~ ·.: ... . .. ,., ·•··•. :;; 

.... ' ~-:;;;;J 

Bet.ween ~;ashington and London ·" _ .. ~ · <:;~~?~t~·' 

A different syst.• bet~en liasbingtan and Nort,h .Atri.~,.:< .. ·,.;;.~ Another system between i1ashington and. the 11:1.dcll.e Eu\ .. :· ..... _ .. : . 

Another system bet11een 'hashington and the Southwest - '··· ... 

·-(1) 

:t ~~~. --{4) 

Pacific 

(5) 

(6) 

A still different system between \.ashingtcm ~d 

Chun:-:k1ng 

J. still ~ifferent system to. be used onl.T in case 

oi' n·~cessity le.teraJJ.t bet.ween theater ccn- · 

mEinders; this system tor the time being to be co;~~:;.on to Pll theaters • 

.!· The toregoinr. i~ merely the first step, which mat be .auppler.iented by further o.pplicr.tion of the s~ principles just aa 

·soon Ea.S cocies L'1d ciphers can be p~pared and adequate stepa ta.km 

in the uar reμa.rtment Classified llessage Center·to handle the 

additional co~es. 

S• Upon ap?roiral of the foregoin , to Security Control for implement£t 

MAR 8 - 1943 

APP•OYSD 

Ji,,,,.,,,. o/fu Seo1rttt .... 1 nr i' ·,.,. 

JOSEPH T. MrNAh~=~v 

. . .~ 'ti~o( S.-n,f 

a,oY.~~ Coi. G.s.c .• .J.11;..~. Sec. ;, ·. i.J,,;. ·•• 

GJ!""X>. V. b'TROl~G, 

Major General., 

Joint Security Control. 

·~i~ I •• • •• 

: ~,;;;::; 

.... L: ·- .·~" ..;_.: •. ~:>:Aj;:~.~~~:i±~l