Alfred Dillwyn "Dilly" Knox, CMG (23 July 1884 – 27 February 1943) was an English classics scholar and papyrologist at King's College, Cambridge and a codebreaker.
[2] As chief cryptographer,[2] Knox played an important role in the Polish–French–British meetings on the eve of the Second World War which disclosed Polish cryptanalysis of the Axis Enigma to the Allies.
He built the team and discovered the method that broke the Italian Naval Enigma, producing the intelligence credited with Allied victory at the Battle of Cape Matapan.
[6] He studied classics at King's College, Cambridge from 1903,[13] and in 1909 was elected a Fellow[6] following the death of Walter Headlam, from whom he inherited extensive research into the works of Herodas.
[2] Among other tasks, he was involved in breaking: Oh, if a time should ever come when we're demobilized How we shall miss the interests which once life comprised!During the First World War he had been elected Librarian at King's College, but never took up the appointment.
Foss found "a high degree of security" but wrote a secret paper describing how to attack the machine if cribs – short sections of plain text – could be guessed.
[3] When – a decade later – Knox picked up this work, he developed a more effective algebraic system (rodding) based on the principles described by Foss.
They were specialists of a different kind, of a different class.Knox attended the second Polish–French–British conference, held on 25–26 July 1939 at the Polish Cipher Bureau (at Pyry, south of Warsaw, Poland).
[21] Although Marian Rejewski, the Polish cryptographer and mathematician who solved the plugboard-equipped Enigma used by Nazi Germany, approached the problem through permutation theory (whereas Knox applied linguistics), a good personal relationship was quickly established at the conference.
The good impression made by Rejewski on Knox played an important role in increasing recruitment of mathematicians to Bletchley Park.
[21] It was such an obvious thing to do, really a silly thing to do, that nobody, not Dilly Knox or Tony Kendrick or Alan Turing, ever thought it worthwhile trying it.After the meeting, he sent the Polish cryptologists a very gracious note in Polish, on official British government stationery, thanking them for their assistance and sending "sincere thanks for your cooperation and patience".
[2] Alan Turing worked on Enigma during the months leading to the outbreak of the Second World War in September 1939, and occasionally visited GC&CS's London HQ to discuss this problem with Knox.
[23] Knox worked in 'the Cottage', next door to the Bletchley Park mansion, as head of a research section, which contributed significantly to cryptanalysis of the Enigma.
[4] Intelligence gained from these Abwehr decrypts played an important part in ensuring the success of the Double-Cross System of MI5 and MI6, and in Operation Fortitude, the Allied campaign to deceive the Germans about D-Day.