Bombe

In the history of cryptography, the bombe was an electromechanical device used by British and American cryptologists to help break German Enigma machine signals during World War II. The bombe was designed by Alan Turing, with an important refinement subsequently contributed by Gordon Welchman.

The British bombe

The bombes were built by the British Tabulating Machine Company at Letchworth. The machine was built under the direction of Harold 'Doc' Keen and was codenamed CANTAB. Each British bombe was about 7 feet wide, 6 feet 6 inches tall and 2 feet deep and weighed about a ton. On the front of each bombe were 108 places where rotors could be mounted. The rotors were in three groups of 12 triplets. Each triplet, arranged vertically, corresponded to the three Enigma rotors. The bombe rotors had a double set of contacts and wiring to emulate the Enigma reflection. The input and output of each triplet of rotors went to cable connectors, allowing the bombe to be rewired according to the Turing and Welchman methodologies as applied to individual ciphertexts.

Related Topics:
British Tabulating Machine Company - Letchworth - Harold 'Doc' Keen

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