John Jeffreys (1952-1956), David Traub (1965-1969), Peter Cohen (1939-1943), Daniel Mades (1970-1974), Nathan Halbrook (1991-1995), Hobart Harmon (1967-1971)
Those working for the Government Code and Cypher School broke the German Enigmacoding machine in 1940 under Dilly Knox, with the mathematicians John Jeffreys, Peter Twinn and Alan Turing where they unraveled the German Army administrative key, according to the Bletchley Park website.