The Bombe a Remarkable Logic Machine

The bombe was an electromechanical machine devised by Alan Turing and Gordon Welchman for breaking the. German Enigma cipher in World War II. The way in which it used a reductio ad absurdum logic to reduce 263 possibilities to a few is a unique example of ingenious circuit design, which is described in detail. Its relationship to the Polish version of the ‘bombe’ is explored. The importance of the diagonal board is shown as is the threat that this device faced from the German's use of the ‘Enigma-Uhr’.