Enigma machine

An Enigma machine was any of a family of related electro-mechanical rotor cipher machines used in the twentieth century for enciphering and deciphering secret messages. Enigma was invented by the German engineer Arthur Scherbius at the end of World War I. 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 most commonly discussed.

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