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Memorandum for General Bryden
October 25, 1940 [Washington, D.C.]
Subject: Secret Documents.
General Miles brought to my attention that very secret papers, such as reports of Japanese diplomatic conversations, were being circularized in this office on an ordinary buck slip. He may have spoken to you about it, but I told him to figure out just how far such circularization should go, and we would carry it out on that basis. I also told him to have prepared special leather folders conspicuously labeled “Secret documents” on the cover, and with instructions as to how they should be handled placed inside the cover. He is to work this up and utilize such means for the further distribution of secret documents.1
Document Copy Text Source: George C. Marshall Papers, Pentagon Office Collection, Selected Materials, George C. Marshall Research Library, Lexington, Virginia.
Document Format: Typed memorandum.
1. As early as 1934 Army Signal Corps cryptanalysts were deciphering certain Japanese diplomatic codes—a process which was given the code name “Magic.“ On March 2, 1935, the Signal Corps began issuing to G-2 bulletins concerning these intercepted messages. In September 1939 Marshall approved the first significant increase in funding for the Signal Intelligence Service. (George V. Strong Memorandum for the Chief of Staff, September 5, 1939 NA/RG 165 [WPD, 4198].) By August 1940 the small Signal Corps group headed by Chief Cryptanalyst William F. Friedman had begun to read the extremely complex machine cipher (designated by United States cryptanalysts as “Purple”) used by the Japanese for very important diplomatic messages. By mid-October a further expansion of the Signal Intelligence Service was being planned. (William F. Friedman, “Expansion of the Signal Intelligence Service from 1930-7 December 1941,” NA/RG 457 [SRH-134], pp. 7, 9-10.)
Recommended Citation: The Papers of George Catlett Marshall, ed. Larry I. Bland, Sharon Ritenour Stevens, and Clarence E. Wunderlin, Jr. (Lexington, Va.: The George C. Marshall Foundation, 1981- ). Electronic version based on The Papers of George Catlett Marshall, vol. 2, “We Cannot Delay,” July 1, 1939-December 6, 1941 (Baltimore and London: The Johns Hopkins University Press, 1986), p. 339.