Enigma was a cypher used by German forces to communicate during World War II. Code-breakers at the Government Code and Cypher School at Bletchley Park cracked the Enigma. The Germans never realised that their codes had been broken, and some historians estimate that cracking the codes shortened the war by as much as four years. (PROSE: A History of Humankind [+]Loading...["A History of Humankind (novel)"])