Enigma machine

An Enigma machine is any of a family of related electro-mechanical rotor cipher machines used for the encryption and decryption of secret messages. Enigma was invented by the German engineer Arthur Scherbius at the end of World War I. The early models were used commercially from the early 1920s, and adopted by military and government services of several countries — most notably by Nazi Germany before and during World War II.^[2] Several different Enigma models were produced, but the German military models are the ones most commonly discussed.

• http://en.wikipedia.org/wiki/Enigma machine