Gordon Welchman

Gordon Welchman

William Gordon Welchman was a British mathematician, university professor, Second World War codebreaker at Bletchley Park and author. After the war he moved to the US, and later took American citizenship.

Welchman was educated at Marlborough College and then studied mathematics as a scholar at Trinity College, Cambridge from 1925 to 1928. In 1929, he became a Research Fellow in Mathematics at Sidney Sussex College, Cambridge, a Fellow in 1932 and later Dean of the College.

Bletchley Park

Just before the Second World War, Welchman was invited by Commander Alastair Denniston to join the Government Code & Cypher School at Bletchley Park, in case war broke out. He was one of four early recruits (the others being Alan Turing, Hugh Alexander and Stuart Milner-Barry), who all made significant contributions at Bletchley and who became known as 'The Wicked Uncles'. They were also the four signatories to an influential letter, delivered to Winston Churchill in October 1941, asking for more resources for the code-breaking work at Bletchley Park. Churchill responded with one of his 'Action This Day' written comments. As stated in his book, most of his work at Bletchley was centered on what was known as "Traffic Analysis" of encrypted German communications. This is roughly described as the practice of examining parts of messages that are standardized descriptors or headers, such as message origination, message destination, time/date information, and so on. Most Cryptographers agree this is markedly easier than attacking cryptographic ciphers directly (although still very complicated and mathematically intensive processing is needed to make initial discoveries), and Welchman is credited with innovating the approach. This led to data analysis techniques that today we describe as "Meta-data" analysis.

Welchman envisaged an enhancement to Alan Turing's improved design of the Polish electromechanical Enigma-cipher-breaking machine, the bombe. Welchman's enhancement, the 'diagonal board', rendered the device substantially more efficient in the attack on ciphers generated by the German Enigma machine. Bombes became the primary mechanical aid in breaking Enigma ciphers during the war, by speeding up the search for current wheel order settings being used with the Enigma machines; these were changed often, initially at least once per day.

Welchman was head of Hut Six, the section at Bletchley Park responsible for breaking German Army and Air Force Enigma ciphers. During his time at Bletchley, Welchman opposed engineer Tommy Flowers' efforts on the Colossus computer (the world's first programmable electronic computer) because Colossus used vacuum tubes.

Post-war

Soon after the end of the war Welchman took up Hugh Alexander’s old post as Director of Research for the John Lewis Partnership before then moving to the United States in 1948 where he taught the first computer course at MIT in the United States. He followed this by employment with Remington Rand and Ferranti.[4] Welchman became a naturalised American citizen in 1962. In that year, he joined the MITRE Corporation, working on secure communications systems for the US military. He retired in 1971 but was retained as a consultant.

In 1982 his book The Hut Six Story was published, initially by McGraw-Hill in the US and by Allen Lane in Britain. The National Security Agency disapproved. The book was not banned but Welchman lost his security clearance (and therefore his consultancy with MITRE) and was forbidden to discuss with the media either the book or his wartime work.

Welchman died in 1985; his final conclusions and corrections to the story of wartime code breaking were published posthumously in 1986 in the paper 'From Polish Bomba to British Bombe: the birth of Ultra' in Intelligence & National Security, Vol 1, No l. The entire paper was included in the revised edition of The Hut Six Story published in 1997 by M & M Baldwin

https://en.wikipedia.org/wiki/Gordon_Welchman

William Gordon Welchman (15 June 1906 – 8 October 1985) was an English mathematician, university professor, Second World War codebreaker at Bletchley Park and author. After the war he moved to the US, and later took American citizenship.

Alan Turing worked in Hut 8 which dealt with breaking the German Navy codes. He designed the Bombe, an early form of computer, to look at all possible settings of the Enigma machine sending the message. Welchman made a very significant contribution to reducing the number of possibilities that had to be considered by the Bombe and greatly enhanced its usefulness. In October 1941 he was one of four who wrote to the British Prime Minister, Winston Churchill, requesting more resources for the codebreaking work at Bletchley Park. The other three who signed the letter were Alan Turing, Hugh Alexander and Stuart Milner-Barry. Churchill's response to the letter was the now famous comment "Action this Day".

After the war ended Welchman did not return to academic life but instead was appointed as director of research for the John Lewis Partnership. In 1946 he was honoured for his contributions during the war when he was given an OBE (Order of the British Empire). However, he decided to move to the United States where he felt he could use the computing skills that he had developed during his time at Bletchley Park. He moved to the United States in 1948 and he taught the first computing course at the Massachusetts Institute of Technology. He then took jobs at Remington Rand and Ferranti.

https://www.findagrave.com/memorial/171102154/gordon-welchman