Files W.F.F. Archive Reports and Research Notes Cipher Security Tests for War and State Departments, 1931-1932
1st Memo Ind. In Reference to A Demonstration of A Cipher Machine Recently Developed by Colonel Parker Hitt
Cipher Printer Unit
Cryptographic Sheet Mag No. 6
Department of State Letter In Reference to Having Mr. W.P. Friedman's Expert Advice of A Cipher Writing Machine
Department of State Letter In Reference to the Cipher Writing Machine
Department of State Letter In Reference to the Test Being Made In This Office of A Cipher Writing Machine
Department of State Letter In Reference to the Test Being Made In This Office of A Cipher Writing Machine
for Testing Cipher Printers
In Reply Refer to Dcr Letter from Department of State
Letter #6 of Set A from Montevideo, Uruguay
Letter of the 29th Ultimo, the Department Has Approved the Recommendation of the Chief Signal Officer
Letter to Major Friedman and Major Crawford from Colonel Parker Hitt
Letter to Major William F. Friedman In Reference to Cable Printer
List of Cipher Codes
Machine No. 1 & 2 Memo by Colonel Parker Hitt
Memorandum for the Administrative Assistant, War Department In Reference to Cipher Machine
Memorandum In Reference to Dealing with Our Solution of Messages Enciphered by the I.T. & T. Company's Electrical Cipher Machine
Memorandum Method of Ascertaining the Notching on the Mixer Dials
Memorandum to Executive Officer
Message #6
Messages Used In Study of Machine
Mr. W.F. Friedman's Investigation Letter of the Cipher Machine Submitted for Your Consideration by the International Telephone and Telegraph Company
Set A-Message #4
Technical Paper of the Signal Intelligence Section
Telegram Signals Received 12:40 P.M
Telegrams Signals from Embassy, Santiago, Chile