One of the best-known electro-mechanical encryption machines is the German Enigma.It was heavily used in WW II, as the Germans improved on the weakness of poor message secrecy in the WWI Zimmerman incident. The machine has 3x10114 possible combinations. The US Navy captured the Enigma machine and several codebooks on the German U-505 submarine in 1944, which lead to the intelligence that helped end the war early.
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