Alan Turing On Breaking The Enigma & Shortening World War II By More Than Two Years

Alan Mathison Turing, English mathematician, computer scientist, logician, cryptanalyst, philosopher, and theoretical biologist, born on June 23, 1912, in Maida Vale, London is a code-breaking war hero and the father of computer science as well as AI. However, he is also known as one of Britain's most famous victims of Homophobia. Between 1885-1967 approximately 49000 homosexual men were convicted of gross indecency under British law.

(© National Portrait Gallery)

He attended Sherborne School at the age of 13, displaying signs of high intelligence and interest particularly in mathematics and science. Later, he enrolled in King's College, the University of Cambridge from 1931 to 1934. During his years in Cambridge, he proved the central limit theorem and thus was elected a fellow at the school upon graduation.

Turing's paper in 1936 on "Computable Numbers, with an Application to the Entscheidungsproblem," where he presented the idea of a universal machine (Turing machine), capable of computing anything that is computable. The Turing machine is now considered a precursor to modern computers. Eventually, he studied mathematics and cryptology at the Institute for Advanced Study in Princeton, New Jersey. Upon receiving his Ph.D. in 1938, he returned to Cambridge and began working part-time with the British Government Government Code and Cypher School.

Turing's had a leading role in breaking Nazi ciphers during WWII, known as Enigma. German U-boats were inflicting high damage to the Allied shipping and thus the need to understand their signals was essential. Using captured Enigma messages, Turing as the head of the HUT 8 team at Bletchley, used his technique Banbarismus to decipher messages from 1941.

(© IWM (COM 921))

Polish mathematicians had solved Enigma messages and the British were aware, but the Germans increased the security by changing the cipher system daily, which made the task of deciphering the code very difficult. Turing had the main role in this, and along with Gordon Welchman invented the machine, called "Bombe". The machine highly reduced the world of the code-breakers and from mid-1940 onwards, German Air Force signals were readable by Bletchley. As a conclusion, the Allies were guided away from the Germans U-boats.

By July 1941, Turing had developed a complex code-breaking technique he called "Turingery", which was used by others at Bletchley as well to understand the Lorenz cipher machine. Germans used Lorenz enciphered strategic messages and thus the Allies benefited from understanding them. In December 1942, Turing traveled to the United States to recommend the use of Bombe machines and share his knowledge of Enigma with US military intelligence. It was in the US that he saw the top-secret speech enciphering system and later in the was developed a speech scrambling system he named "Delilah".