As a mathematician at Bletchley Park, he was the first man to break open a signal encoded by the German Enigma machine
British mathematician and WWII code-breaker who was recruited as an Enigma cipher-breaker into the British Government Code & Cipher School (GC&CS) before the war and was later credited with being the first British cryptographer to break an Enigma cipher, which embarrassed him and led him to dismiss its significance, whose work was of particular importance during the Fortitude deception operation that helped to ensure the success of the D-Day landings, died on October 29, 2004. ( Source Find a Grave)