Alan Turing: the man with the secrets


Le film Imitation Game, sorti en janvier de cette année, réalisé par Morten Tyldum, retrace la vie d’Alan Turing, le mathématicien et cryptologue qui a créé le premier ordinateur et joué un rôle majeur pendant la seconde guerre mondiale. Ses travaux de cryptographie sur la machine Enigma durant la seconde guerre mondiale ont permis de raccourcir la guerre considérablement et de sauver des millions de vies.


Born in 1912, Alan Turing was rapidly deemed a gifted and well-rounded student. At the age of 13, during the 1926 general strike, he rode 90 kilometres on his bike in order to start his school year. From 1931 he studied at Cambridge University.

When WW2 began he was recruited by the Government Code and Cypher School with the task of deciphering the Germans’ coding machine. Enigma could produce 158, 962, 555, 217, 826, 360, 000 coding possibilities, while Alan Turing’s machine could only test a thousand combinations per second: at this pace, it would have taken 5 billion years to test every possibility. Furthermore the Germans changed Enigma’s settings every day at noon, which meant that the tests made during the day were already obsolete.


But there was an Achille’s heel: the Nazis sent a weather report every morning with the words “Wetterbicht” (weather report) and “Heil Hitler!”. This flaw  enabled Turing’s machine – the first computer ever built – to decipher the Enigma settings of the day in less than 20 minutes. Although, the code was decrypted and the allies knew the Nazis’ military orders of the day, they could not lead attacks at every opportunity because the Germans would have understood that Enigma was not safe anymore.

After the war ended, Alan Turing kept working on his research. Unfortunately for him, homosexuality was a felony because of the 1885 Criminal Law Amendment Act. Although his sexual orientation had not been unknown, Alan Turing was arrested in 1952 and charged with “gross indecency” . He was later given the choice between imprisonment or undergoing a hormone treatment designed to reduce libido. At the time his work during the war was kept classified – it was only revealed in 2000 – so no one could plead for him using those arguments. The treatment induced a strong depression and in 1954 he was found dead in his apartment, with a crunched apple by his side.

It is said that Turing ate an apple because an apple’s pip can naturally contain cyanide and he wanted his mother to believe it was an accident. Apparently it could also be a homage to Snow White, as he took “an especially keen pleasure in the scene where the Wicked Queen immerses her apple in the poisonous brew“, Turing’s biographers wrote. And the apple was never analysed…


Apple executives have denied multiple times that their logo paid homage to Turing’s legacy. They have also denied the refutation of it several times…

In December 2013, Queen Elizabeth granted her royal pardon to Alan Turing posthumously.

Boris BOIDRON & Pierre DAVID


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