However I have to disagree with the following statement:
‘One of Friedman’s reasons for visiting TICOM was to confirm that the Germans had been unable to break any Allied high-grade encryption systems during the war. That spring, senior Army officers had asked why he was so confident that these systems remained invulnerable. Friedman responded that captured German documents contained no suggestion any major Allied systems had been broken, only the less sophisticated M-209 device and even then only when Allied code clerks made mistakes. ‘The overwhelming evidence’ Friedman concluded, ‘is that they are far behind us and have no appreciation of solution techniques we now regard as commonplace.’ For him, the Germans’ inability to penetrate Allied cryptographic systems reflected their ‘supreme confidence’ in Enigma. What Friedman learned from the TICOM effort confirmed his view that British and American successes in cryptanalysis and cryptography far exceeded those of the Germans’.
cough Compromise of US cipher teleprinter in 1944 cough United States cryptologic security failures in WWII cough
2). From ‘Intelligence and National Security’: ‘Protecting secrets: British diplomatic cipher machines in the early Cold War, 1945–1970’.
Regarding Typex it says that model 22 (with movement of all 5 rotors and two plugboards) was introduced in 1950 and not during WWII as claimed by some sites:
‘In 1946, the British authorities decided to further modify Typex to increase its cryptographic strength. The rotors and turnover mechanism were redesigned so that all rotors would turn as a message was encrypted and the machine was fitted with a pluggable ‘crossover’ at the entry and exit to the wiring maze. This new version of Typex was ready for service in September 1950 and it was predicted that it would provide adequate cipher security for another 10 years.’