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’.
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.’
Regarding the cryptologic strength of the M-209 machine versus the plugboard Enigma, the expert on classical cipher systems George Lasry (15) has stated:
‘One comment about the security of the M-209. The claim that the Enigma is more secure than the M- 209 is disputable.
1) The best modern ciphertext-only algorithm for Enigma (Ostward and Weierud, 2017) requires no more than 30 letters. My new algorithm for M-209 requires at least 450 letters (Reeds, Morris, and Ritchie needed 1500). So the M-209 is much better protected against ciphertext-only attacks.
2) The Turing Bombe – the best known-plaintext attack against the Enigma needed no more than 15-20 known plaintext letters. The best known-plaintext attacks against the M-209 require at least 50 known plaintext letters.
3) The Unicity Distance for Enigma is about 28, it is 50 for the M-209.
4) The only aspect in which Enigma is more secure than M-209 is about messages in depth (same key). To break Enigma, you needed a few tens of messages in depth. For M-209, two messages in depth are enough. But with good key management discipline, this weakness can be addressed.
Bottom line – if no two messages are sent in depth (full, or partial depth), then the M-209 is much more secure than Enigma’.
This year I continued to research several cases of cryptologic history, I copied material from the US and UK national archives and I received reports from the NSA’s FOIA office. I also received some interesting files from friends of mine.
1). Original information was presented in the following essays:
In July 1943 US and British troops invaded the island of Sicily and after more than a month of fighting defeated the Axis forces and captured the island. However the German forces were able to avoid a total defeat by retreating in an orderly fashion through the Strait of Messina.
It seems that during the fighting in Sicily the Germans managed to capture a valid keylist of an M-209 network and thus read current US military traffic (14).
The war diary of Inspectorate 7/VI says that in July ’43 the captured material allowed the continuous decryption of the traffic with indicator ‘ID’ and the results were communicated to NAAst 7.
The report of August ’43 says that messages of the ‘ID’ network could be decoded till mid month and after that it was still possible to find several cases of indicator reuse and thus solve the traffic of those days cryptanalytically.
I’ve always been interested in the Asia Minor campaign but unfortunately the books I’ve read so far tended to lack an in depth analysis of why the Greek forces failed to defeat the weakened Kemalist army.
The essays posted at the aforementioned site clearly point out the underlying problems of the Greek armed forces: the lack of professionalism of the officer corps, the rigid planning at the operational and strategic level and the lack of support between infantry, artillery and cavalry.