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I. EXPLANATION AND HISTORY OF INFORMATION
is a small group of cryptographers attached to the National Security Agency (NSA) who work on deciphering certain Soviet intelligence messages covering the period 1942–46. These Soviet messages are made up of telegrams and cables and radio messages sent between Soviet intelligence operators in the United States and Moscow. Consequently, this material falls within the category of communications intelligence information and as such is subject to the most stringent regulations governing dissemination on a "need-to-know" basis. These messages would seem to fall into the same category as teletypes from a field office to the Bureau (in code) and detailed reports were undoubtedly being sent by the MGB (Soviet Intelligence Service) in the diplomatic pouch. The usual Russian method in concealing the text of these messages is to first translate the Russian plaintext into code by using a code book and then apply a one-time pad to the code, thus making it practically impossible to recover the message. Interceptions of the messages were made by the U.S. Army. The intercepted messages consist of a series of numbers. These numbers are placed on work sheets by and efforts are then made to arrive at the additive (the enciphering process). Once the additive is correctly determined the message can be read by using the MGB code book which has been partially reconstructed by NSA. The chief problem is to develop the additive. This requires painstaking effort by experienced cryptographers who can also translate Russian. Both and work on this problem and work sheets have been made up by and sent to . Also, has a man in England working with . In turn, have a cryptographer working full-time at .
The first report received by the Bureau on MGB deciphered traffic was received from Army Security Agency (predecessor of NSA) 4/16/48. Colonel L.E. Forney, Intelligence
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