Enigma

Enigma was a cipher device used by Nazi Germany’s military command to encode strategic messages before and during World War II.

The number of permutations of settings available to the encoders made the Enigma code difficult to break. The operator set the machine’s rotating wheels and plugboard to different predetermined positions according to daily orders, regularly changing the cipher.

The Enigma machine produced encoded messages. Electrical signals from a typewriter-like keyboard were routed through a series of rotating wheels as well as a plugboard that scrambled the output but did so in a way that was decipherable with the right settings.

In 1932–33 Polish mathematician Marian Rejewski deduced the wiring pattern inside the wheels of Enigma, assisted by Enigma operating manuals provided by the French secret service, to make a successful decryption machine. When the Germans improved their encryption, rendering Rejewski’s work outdated, English mathematician Alan Turing developed a more advanced machine that was deciphering Enigma messages by 1940.

The Enigma code was broken through the collaboration of the French secret service, the Polish Cipher Bureau, and the British government cryptological establishment, Bletchley Park. Although all these agencies contributed to breaking Enigma, the roles of Polish mathematician Marian Rejewski and English mathematician Alan Turing were essential.