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e REF ID:A2435771e 

S~CRET 

- ~-_-.. 

24 March 1944 

MEMORANDUM lfOR Secui;ity Section 

I. Th~ following information was gathered through discussion with 

Colonel Fahne~tock, Chief, G-2 Classified Message Center,.Major Battin 

of Special Branch, G-2, and Lt. Fo}"bes, Security Officer, War Department · Code Center, in regard to a memo from G-2 dated 11 March 1944, Subjecti 

Handling and Distribution of Messages Concerning Qombined Subjects. 

1. That 51 copies of messages in the T.AM-MAT series are made ... _ . - -_;_' 

by War Department Classified Message Center as listed in Annex 2, this 

memo. Similar distribution is given to the GAL-LAC, GOV-VOG, LEM-MGL, 

NAF-:PAN, FAcs..;.scAF, MEG-GEM, and BOC-COB series. Only in one instance 

is paraphrase attempted despite regulations in AR 380-5 cited in Annex 1. 

Messages to the State Department are sometimes paraphrased although the 

original copy is usually seen by the State Department before paraphrase 

is attempted. 

2. ·Thirteen copies of the original messages are given to the 

British without paraphrase. The British distribution is not eXa.ctly 

known although undoubtedly original copies wind up in the British 

Embassy, the British Message Center, British Chiefs of Staff and the 

British War Office. Therefore, although some attempt is made to paraphrase messages sent to our own State Department, the British .Embassy 

and War Office are furnished with the original version. It is also 

believed that a copy of the original message reaches the British inner 

sanctum where it is available for cryptanalytic study. 

J. Most of the traffic sent in the TAM-MAT, etc. series has - been in SIGABA. The SIGABA has always been regarded as the backbone 

of' cryptographic col)i.munication in both the U. s. Army and U. s. Navy 

and theref'ore the utmost enforcement of physical and cryptographic 

security has always been afforded this equipment. Regulations have 

been issued forbidding the showing or discussion of SIGABA with the 

representatives of any nation but our own. However, from the above 

information it appears that, for an undetermined time, the British have 

been given the opportunity for unlimited exploit of the SIGABA from a 

cryptanalytical point of view. 

4. All of the traffic to War Department in the TAM-lVIA.T etc. 

series is sent through regular War Department channels and must clear through 

either London or Algiers. Both London and P..lgmers are now equipped with 

and are now using one time tape systems. Therefore, it would be an easy 

matter to route all traf'fic in the TAM-MAT etc aeries over SIGTOT c~nnels. 

This would eliminate the need for paraphrase in any case and would also 

COPY 

.s&::RE'f LI /' , I cf_ 

Declassified and approved for release by NSA on 09-19-2013 pursuant to E .0. ·1352'a 
.. REF ID:A2435771 

SECRET 

COPY 

save the SIGABA from further exposure. 

II Recommendations: 

1. That a directive be issued by G-2 stating that all traffic 

in the TAM-MAT etc series be transmitted only in SIGTar. 

2. That an effort be made to restrict similar traffic where 

distribution of unparaphrased messages is made to a government other 

than the U. S. or to another agency in our government to one-time systems. 

3. That an investigation of the practices referred to above be 

instigated and that every effort be made to enforce the security regulations. On the face of it, this looks like one of the most serious 

threats to the security of our cryptographic systems that has yet come 

to light. 

COPY 

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SECRET 

William A. Eenning Jr. 

1st Lt., Signal Corps 

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