Cryptograph "Bombe" (Date of photograph unknown)
US Navy Bombe decryption machine and operator. Based on the design by mathematician Alan Turing, this device was used during World War 2 to decrypt German communications enciphered with the Enigma machine. The bombe was used to work out the Enigma settings in use each day, allowing messages to be deciphered. It required a short stretch of encrypted message with a known meaning (a crib). It was named after the Bomba, a machine used by Polish cryptographers to break simple variants of Enigma before the war.