Re: Enigma
Being Briefed on ULTRA did not include the details of how the Enigma decrypts worked. Clark only understood valuable intellegence came from reading high level German radio traffic, but not on the workings of Beltechy Park and the Bombe decryption machines.
The Germans never discounted the idea Enigma could be 'broken'. What they did not understand were two things: 1. The Poles had managed to find the actual mathmatical basis of the machines function, & in doing so discovered the number of combinations on the rotors were actually far less than the manufactor and German radio security people calculated.
2. The Poles had contrived a machine basis for rapidly finding the Enigma keys or rotor settings.
The Germans thought that by traditional methods the key or rotor setting could be found for a specific message. But, traditional methods would have to sift through billions of combinations. Once the key was found for a message it was only good for that or a few other messages. The Germans did eventually suspect rapid methods were in use, but they did not understand how rapid. They thought that adding rotors, the Stecker Board, and better operator procedures were sufficient to stay ahead any enemy efforts.
Bottom line here is if they learn from Clark the Enigma encrypted messages are being read they would only thighten procedures, add another rotor, or maybe make the Stecker board more complex. That could shut the Allies out of the Enigma messages for a few months, but that happened several times during the war and proved not to be a severe handicap. Alternatives to the Enigma machine were not in easy reach in 1942, plus replacing the thousands of machines in use would be a colossal logistics task. Germany had nothing like the NCR or IBM factories for mass producing those numbers in a few months.