William F. Friedman NSA Archive - SISDE-11 Drawings, 1931-1935 - 4in1

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Files W.F.F. Archive Patent and Equipment Records SISDE-11 Drawings, 1931-1935

Drawings of Friedman/Rowlett Cryptographic Device, Application Serial No. 70,412

Document A557818

Patent 2,395,863, Cryptographic Device, William F. Friedman

Document A557819