Rotor machine

In cryptography, a rotor machine is a electro-mechanical device used for encrypting and decrypting secret messages. Rotor machines were the cryptographic state-of-the-art for a brief but prominent period of history; they were in widespread use in the 1930s–1950s. The most famous example is the Enigma machine.

Related Topics:
Cryptography - Encrypting - 1930 - 1950s - Enigma machine

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The primary component is a set of rotors — rotating disks with an array of electrical contacts on either side. The wiring between the contacts implements a fixed substitution of letters, scrambling them in some complex fashion. On its own, this would offer little security; however, after encrypting each letter, the rotors advance positions, changing the substitution. By this means, a rotor machine produces a complex polyalphabetic substitution cipher.

Related Topics:
Electrical contact - Substitution - Polyalphabetic substitution

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