Alfred Dillwyn "Dilly" Knox, CMG (23 July 1884 – 27 February 1943) was a British classics scholar and papyrologist at King's College, Cambridge and a codebreaker. As a member of the Room 40 codebreaking unit he helped decrypt the Zimmermann Telegram which brought the USA into the First World War. He then joined the Government Code and Cypher School (GC&CS). As Chief Cryptographer, 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.