Four-rotor German Enigma cypher machine, 1939-1945.

GERMANY - SEPTEMBER 30: A four-rotor German Enigma cypher machine with a second operator display (a 'remote lampboard'), made during World War II. This type of machine, devised by the German Navy in 1939, was used to encode wartime messages requiring a particularly high degree of security. The cracking of German cypher codes by Allied intelligence was a major achievement in cryptanalysis and played a key role in the outcome of the North Atlantic U-boat engagements. The search to crack the the Enigma codes also resulted in �Colossus�, the first all-electronic digital computer. This rare machine is thought to have been used in the post-war years for coding diplomatic traffic in Switzerland. (Photo by SSPL/Getty Images)