Enigma machine. Enigma encryption machine used by the Germans in World War 2 to send messages in code. It is seen with volumes of Lloyd's Register that catalogue the loss of ships at sea. This electromechanical machine used three rotors and a complicated algorithm to encode messages which were typed in on its keyboard. Each letter could be represented by any other letter in the alphabet. So complex was Enigma that the same key pressed twice would produce two different encryption characters. Enigma was the German's main coding device, and was used to direct their submarines to attack enemy shipping convoys. The code was eventually deciphered by the Allies.