RE: WW2 Codebreakers to Be Recognized with Plaque In St. Paul

Andrew J — Sat, 17 Jun 2023 13:00:26 GMT

There’s a lot in The Imitation Game that isn’t correct. That’s fine, it’s a movie designed to entertain and the actual story would have made for a dull 2 hours! You can get some idea of the practicalities and realities of breaking Enigma and using the information gleaned from it though. The Bombe isn’t in any sense a computer, but a fancy circuit tester: when the circuit goes open, there’s an indication of a possible solution to one encrypted message (and thus all messages on that Enigma network for 24 hours - upwards of 70 networks, all using different settings.) Incidentally, and more in relation to code breaking in the US, when the German submarine fleet moved to a 4 rotor Enigma, the British developed a 4 drum Bombe machine - an adaptation of the 3 drum machine - but these were mostly built/modified and run by the US Navy who concentrated on Submarine traffic leaving the British to concentrate on other networks.

Turing and the team at Bletchley were originally using mathematical techniques, building on the work of Polish cryptographers, to break Enigma (which had changed since the Polish first broke it) but this was way too slow to be of use. Turing did envisage a machine to do this and worked with Harold ‘Doc’ Keene, Chief Engineer at the British Tabulating Machine company in Letchworth who actually built the machine(s) - Turing definitely did not lock himself in a shed and build it! Also, it required another mathematician, Gordon Welchman, to have the insight that actually made the machine practical and without whom the whole project may well have been abandoned (maybe Turing would have come up with the insight eventually.)

For a real consideration of the earliest computer (arguable it seems) used for code breaking, see Colossus and the breaking of the German Lorenz cipher, again at Bletchley Park. That is a truly amazing story of mathematical genius.

Not taking away from what the US cryptologists did of course, their recognition is well deserved; nor indeed the work of Von Neumann and ENIAC for calculating ballistic trajectories and defining a hardware architecture that has stood the test of time.

The UK had a not dissimilar trajectory of companies that formed and merged throughout the 50s and 60s, resulting in ICL (as one example). Some of the most interesting stories come from the early pre-standards days (decimal computers and CRTs as RAM anyone?)