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8. ' · ~ EXl!CUTIVI! DIVISION fl' MIUTAAY INTl!LLIGl!NCE BRANCH REF ID :·A4148924 . .--.. 

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JMM I In replying refer to ' 

4131-526 

M.I .a. 

WAR DEPARTMENT 

OFFICE OF THE CHIEF OF STAFF 

WAIHlolGITON. 

April ' 1919. 

MEMORANDUM FOR THE CHIEF OF STAFF· 

Subject: The T. and T. ~ipher System. 

l. Attached is a letter to the Secretary of War from 

Mr. George Fabyan, of Geneva, Illinois, in which Mr. Fabyan 

transmits a decipherment of a cipher message which he asserts 

was submitted to him -oy the .American Telephone and Telegraph 

Compe.ll1' as a test message ttfor the plll'pOBe of ascertaining 

the possibility of its decipherment by the enemyn a.nd on the 

basis of this decipherment asserts that "the enemy can decipher messages sent by th.is system." 

2. I:na.smuch as the A· T. and T. system has been and is 

used for Army messages of the highest importance a.nd is re~~­

ed by Army experts as absolutely indecipherable, a caretul i~­

ves tiga. ti on of Mr. ~J>yan • s claims has been made. 

3. It appears: 

a} That the message deciphered was n~t submitted 

as a test message but as one of two concerning which it was expressly stated that ~~ey undoubtedly could be deciphered and 

that they did not represent the system in use. 

b) '.l!h.a.t of the four messages suomitted to Mr. 

Fab;yan on June 11, 1918, as test messages, not one na.s been 

solved. 

4. It is recommended that the attached letter. signed by 

the Acting Secretary of War, be sent to Mr. Fabyan. 

2 enc. 

bbm 

•i 

M. Churchill, 

Brigadier General, General Staff, 

Director of Military Intelligence. 

J 

@'pp roved for Release by NSA on 11-19-2014 pursuantto E .0. 1352\3 

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