Files W.F.F. Archive Patent and Equipment Records Patent Data SISDE-4, Serial No. 350,713, Patent No. 1,857,374, Cryptograph, Evans, Friedman, and Graham (1924), 1923-1924
Cryptographic Machine Description
Description of Devices for Enciphering Teletype Messages; Invention of William F. Friedman Et AL
Description of New Device to Encode and Decode Teletype Messages; Text and Drawings AS Conceived by William F. Friedman Et AL
Description of Typewriter Cryptographing Machine by William Friedman; Text and Drawings
Modification of Teletype Apparatus for Cryptographic Purposes; Memo from Colonel McClure, Signal Corps to the Personnel Division, Training Section
Notes Between William Friedman, Major Evans , and Mr. Graham Concerning Patent Issue
Proposal for Modifying Teletype Apparatus for Cipher Purposes; Conceived by William F. Friedman, Cryptanalyst, Signal Corps