How did Alan Turing contribute to World War II codebreaking?

During World War II, mathematician Alan Turing worked at Bletchley Park as the head of Hut 8, focusing on decrypting German naval messages. He provided the original thinking that improved the pre-war Polish bomba method, helping the Allies decipher messages encrypted by the German Enigma machine and produce critical intelligence known as Ultra.

What we know

• Alan Turing worked at the Government Code and Cypher School at Bletchley Park and headed Hut 8, where he concentrated on decrypting German naval messages. [2, 4]
• Turing provided much of the original thinking that led to the upgrading of the pre-war Polish cryptologic bomb used for cracking Enigma ciphers. [4]
• The cryptanalytic work involving Turing hastened the reading of Enigma systems and generated intelligence codenamed Ultra, which aided the Battle of the Atlantic. [2, 4]

Where to go next

• how it workedWhat was the Polish cryptologic bomb?
• how we knowHow did the Enigma machine work?
• whereWhat was Bletchley Park during World War II?
• what followedHow did Ultra intelligence affect World War II?
• the bigger pictureWhat is the Turing Award in computer science?
• an unexpected connectionHow does a codebreaking pioneer connect to artificial intelligence and morphogenesis?Alan Turing is celebrated for wartime codebreaking, yet he also founded theoretical computer science, proposed the Turing test in philosophy, and contributed to mathematical biology through morphogenesis.

Sources

• [1]Alan Turing (Wikidata Q7251) · CC0 1.0
• [2]Alan Turing · CC BY-SA 4.0
• [3]Cryptanalysis · CC BY-SA 4.0
• [4]Cryptanalysis of the Enigma · CC BY-SA 4.0
• [5]Turing Award · CC BY-SA 4.0