The Enigma code was a complex cipher used by the German military during World War II to encrypt messages. It employed a machine called the Enigma machine, which used a series of rotating wheels to scramble letters, making the messages difficult to decode without the correct settings. The code was considered unbreakable at the time, but a team of mathematicians and cryptanalysts, including Alan Turing, successfully deciphered it at Bletchley Park. This breakthrough significantly contributed to the Allied victory by allowing them to intercept and understand German communications.