Question: What specialism did Alec Naylor Dakin, fellow of Oxford College, pursue at Bletchley Park during the second World War; a central site for British codebreakers?

full_context: Document 1: Alan Turing: Alan Mathison Turing ( ; 23 June 1912 – 7 June 1954) was an English computer scientist, mathematician, logician, cryptanalyst, philosopher and theoretical biologist.
Document 2: Heath Robinson (codebreaking machine): Heath Robinson was a machine used by British codebreakers at the Government Code and Cypher School (GC&CS) at Bletchley Park during World War II in Cryptanalysis of the Lorenz cipher. This achieved the decryption of messages in the German teleprinter cipher produced by the Lorenz SZ40/42 in-line cipher machine. Both the cipher and the machines were called "Tunny" by the codebreakers, who named different German teleprinter ciphers after fish. It was mainly an electro-mechanical machine, containing no more than a couple of dozen valves (vacuum tubes), and was the predecessor to the electronic Colossus computer. It was dubbed "Heath Robinson" by the Wrens who operated it, after cartoonist William Heath Robinson, who drew immensely complicated mechanical devices for simple tasks, similar to (and somewhat predating) Rube Goldberg in the USA.
Document 3: Susan Elizabeth Black: Susan Elizabeth Black {'1': ", '2': ", '3': ", '4': "} (born 1962) is a British computer scientist, academic and social entrepreneur. She has been instrumental in saving Bletchley Park, the site of World War II codebreaking, with her "Saving Bletchley Park" campaign.
Document 4: Bletchley Park: Bletchley Park was the central site for British codebreakers during World War II. It housed the Government Code and Cypher School (GC&CS), which regularly penetrated the secret communications of the Axis Powersmost importantly the German Enigma and Lorenz ciphers. According to the official historian of British Intelligence, the "Ultra" intelligence produced at Bletchley shortened the war by two to four years, and that without it the outcome of the war would have been uncertain.
Document 5: Banburismus: Banburismus was a cryptanalytic process developed by Alan Turing at Bletchley Park in England during the Second World War. It was used by Bletchley Park's Hut 8 to help break German "Kriegsmarine" (naval) messages enciphered on Enigma machines. The process used sequential conditional probability to infer information about the likely settings of the Enigma machine. It gave rise to Turing's invention of the "ban" as a measure of the weight of evidence in favour of a hypothesis. This concept was later applied in Turingery and all the other methods used for breaking the Lorenz cipher.
Document 6: Enigma machine: The Enigma machines were a series of electro-mechanical rotor cipher machines developed and used in the early- to mid-20th century to protect commercial, diplomatic and military communication. Enigma was invented by the German engineer Arthur Scherbius at the end of World War I. Early models were used commercially from the early 1920s, and adopted by military and government services of several countries, most notably Nazi Germany before and during World War II. Several different Enigma models were produced, but the German military models, having a plugboard, were the most complex. Japanese and Italian models were also in use.
Document 7: Japanese naval codes: The vulnerability of Japanese naval codes and ciphers was crucial to the conduct of World War II, and had an important influence on foreign relations between Japan and the west in the years leading up to the war as well. Every Japanese code was eventually broken, and the intelligence gathered made possible such operations as the victorious American ambush of the Japanese Navy at Midway (JN-25b) and the shooting down of Isoroku Yamamoto in Operation Vengeance.
Document 8: Kiss (cryptanalysis): In cryptanalysis, a kiss is a pair of identical messages sent using different ciphers, one of which has been broken. The term was used at Bletchley Park during World War II. A deciphered message in the breakable system provided a "crib" (piece of known plaintext) which could then be used to read the unbroken messages. One example was where messages read in a German meteorological cipher could be used to provide cribs for reading the difficult 4-wheel Naval Enigma cipher.
Document 9: Michael Smith (newspaper reporter): Michael Smith is a British author who specializes in spies and espionage. He is also the Bletchley Park Fellow at Kellogg College, Oxford, and a member of the board of the Bletchley Park Trust.
Document 10: John Cairncross: John Cairncross (25 July 1913 – 8 October 1995) was a British civil servant who became an intelligence officer and spy during the Second World War. As a Soviet double agent, he passed to the Soviet Union the raw Tunny decrypts that influenced the Battle of Kursk. He was alleged to be the fifth member of the Cambridge Five.
Document 11: Denys Page: Sir Denys Lionel Page, FBA (11 May 1908, Reading, Berkshire – 6 July 1978, Tarset) was a British classical scholar at Oxford and Cambridge universities. He was President of the British Academy from 1971–74.
Document 12: Cryptonomicon: Cryptonomicon is a 1999 novel by American author Neal Stephenson, set in two different time periods. One group of characters are World War II-era Allied codebreakers and tactical-deception operatives affiliated with the Government Code and Cypher School at Bletchley Park (UK), and disillusioned Axis military and intelligence figures. The second narrative is set in the late 1990s, with characters that are (in part) descendants of those of the earlier time period, who employ cryptologic, telecom and computer technology to build an underground data haven in the fictional Sultanate of Kinakuta. Their goal is to facilitate anonymous Internet banking using electronic money and (later) digital gold currency, with a long-term objective to distribute Holocaust Education and Avoidance Pod (HEAP) media for instructing genocide-target populations on defensive warfare.
Document 13: Alec Jeffreys: Sir Alec John Jeffreys, (born 9 January 1950) is a British geneticist, who developed techniques for RNA fingerprinting and DNA profiling which are now used worldwide in forensic science to assist police detective work and to resolve paternity and immigration disputes. He is a professor of genetics at the University of Leicester, and he became an honorary freeman of the City of Leicester on 26 November 1992. In 1994, he was knighted for services to genetics.
Document 14: Women in Bletchley Park: About 8,000 women worked in Bletchley Park, the central site for British cryptanalysts during World War II. Women constituted roughly 75% of the workforce there. While women were overwhelmingly under-represented in high-level work, such as cryptanalysis, they were employed in large numbers in important auxiliary work, such as: operating cryptographic machinery and communications machinery; translating of Axis documents; traffic analysis; clerical duties, and many more besides.
Document 15: Alec Naylor Dakin: Alec Naylor Dakin (3 April 1912 – 14 June 2003) was a Fellow of Oxford College, a cryptologist at Bletchley Park, an Egyptologist and schoolmaster.
ground_truth: cryptologist