Enigma machine

The Enigma machine is an electromechanical cipher device developed in the early twentieth century to protect commercial, diplomatic and military communications. The German engineer Arthur Scherbius invented it at the end of the First World War, and his firm Scherbius and Ritter patented ideas for the cipher machine in 1918 and began marketing it under the Enigma brand in 1923, first to commercial customers. A person types text on a keyboard, and one of 26 lamps above it lights for each key press; a set of rotors changes the electrical connections between keys and lamps with every press, so each letter is enciphered with a different key, and the same settings used on a second machine turn the ciphertext back into plain text. The German Navy adopted a modified form in 1926 and the Army and Air Force soon afterwards, adding a plugboard that made the military models the most complex. Poland first broke the machine in December 1932 through the work of Marian Rejewski, and the Allies later used its decrypts as a major source of intelligence.