Mr Turing worked as part of the team which cracked the Enigmacode at Bletchley Park in World War II and went on to help create the world's first modern computer, the Manchester Small-Scale Experimental Machine.
Even while British code breakers were cracking the Enigma machine and altering the course of the war, Americans were developing one of the most secure, efficient forms of encryption, which was also one of the simplest.
Bletchley Park was the wartime home of the Government Code and Cypher School which broke the codes generated by the German Enigma machine, using the Bombe.