The Turing Guide

116 | 12 BOmBES

The bombes were special-purpose electromechanical computers. What they did was to
search at superhuman speed through different configurations of the Enigma’s wheels, looking
for a pattern of keyboard-to-lampboard connections that would turn the coded letters into
plain German. As Mahon joked, ‘The bombe was rather like the traditional German soldier,
highly efficient but totally unintelligent’.^53 Some would say, however, that there was indeed a
glimmer of intelligence in the bombe, even though at root the machine depended completely

entry plate

wheel core wheel-adjuster

fast wheel

ring

middle wheel

slow wheel

reflector

lamp-board

keyboard

plugboard

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figure 12.4 How the Enigma machine encrypts.

Jack Copeland and Dustin Parry. All rights reserved.