William F. Friedman NSA Archive - Memoranda, Drawings, and Cryptograph Specifications Description, SISDE-6 SIS (Signal Intelligence Service) System-Message Authentication, 1933-1935 - 4in1

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Files W.F.F. Archive Patent and Equipment Records Memoranda, Drawings, and Cryptograph Specifications Description, SISDE-6 SIS (Signal Intelligence Service) System-Message Authentication, 1933-1935

Memo Re Patent Regulations and Approval

Document A70302

Patent Application: Cipher Device

Document A70304

Patent Application: Cipher Device-- Specifications, Claims, Drawings

Document A70313