Enigma machine out of its wooden box

Lorenz SZ42 machine with covers removed

Part of Japanese PURPLE machine with covers removed

Ultra was the name given by British military intelligence for the attack on German military codes in World War II. It included the Enigma machine and, later, the Japanese Purple machine.

The work on Enigma started before the war, when Polish cryptographers smuggled out an Enigma machine to England. The codename 'Ultra', however, was only given to the work in 1941.