Alan Turing

Mathematician, head of Hut 8 at Bletchley Park, and the man who broke the German naval Enigma. Born on 23 June 1912 in London. He read mathematics at King's College, Cambridge, and in 1936 published "On Computable Numbers", introducing the abstract computing machine that became the foundation of theoretical computer science a decade before any computer existed. He took his doctorate at Princeton in 1938. On 4 September 1939, the day after war was declared, he reported to the Government Code and Cypher School at Bletchley Park. He led Hut 8, which worked on naval Enigma, the most heavily protected of the German cipher systems. He designed the Bombe, an electromechanical machine that ran through possible rotor settings and discarded those that contradicted themselves. Its crucial refinement, the diagonal board, was Gordon Welchman's, working in Hut 6. Turing also devised Banburismus, a statistical method that sharply reduced the search. Reading naval Enigma had a direct consequence in the Atlantic: convoys could be routed away from the wolf packs rather than hunted after an attack had begun. Britain's supplies, and the shipments to Murmansk and Archangel, depended on those convoys. He was appointed OBE in 1946. After the war he worked on computing machines at the National Physical Laboratory and at Manchester, and in 1950 published the paper with which artificial intelligence begins as a field. In 1952 he was convicted for homosexuality, subjected to enforced hormone treatment and stripped of his security clearance. He died on 7 June 1954 of cyanide poisoning. The British government issued a formal apology in 2009, and he was pardoned posthumously in 2013.