The ENIGMA machine was a German encryption device used during World War II. It was an electromechanical device that used a series of rotors to encrypt and decrypt messages. The machine was developed by Arthur Scherbius in 1918 and was used by the German military to send coded messages. The Allies were able to break the code by using a combination of intelligence gathering and cryptanalysis. The ENIGMA machine is considered one of the most important inventions of the 20th century and is still studied today.