The ENIGMA machine was an encryption device used by the Germans during World War II. It was famously cracked by Alan Turing and his team at Bletchley Park, as depicted in the 2014 film The Imitation Game. The ENIGMA machine was a complex device that used a combination of rotors, plugs, and wiring to encrypt messages. It was considered unbreakable until Turing and his team developed a method to decipher the code.