By Phoebe Jones

What is Enigma?

The Enigma machine is a piece of hardware invented by a German and used by Britain codebreakers as a way of deciphering German signals traffic during World War Two. The Enigma is a device which scrambles a plain text message into a ciphered text. It was used solely to encipher and decipher messages. It consisted of a keyboard of 26 letters in the pattern of the normal German typewriter, but with no keys for numerals or punctuation. Behind the keyboard was a lampboard made up of 26 small circular windows, each bearing a letter in the same pattern as the keyboard, which could light up one at a time. Behind the lampboard is the scrambler unit consisting of a fixed wheel at each end, and a central space for three rotating wheels. If a key was pressed on the keyboard any other letter could light up, and the sequence would only repeat itself after 16,900 (26x25x26) keyings, when the inner mechanism returned to the same position. Messages were limited to a maximum of 250 letters to avoid this recurrence, which might have otherwise helped the British code-breakers.

What does it look like?