The Enigma machine was an encryption device used by the German armed forces during the Second World War. Alan Turing and others at Bletchley Park developed the Bombe a device to help decrypt Enigma machine messages. This was one of the inspirations for his later work studying computation.
Used in Chap. 1: page 4
Links:
bletchleypark.org.uk: Bletchley Park: Enigma- YouTube: The Enigma Cipher Machine | Bletchley Park
- tnmoc.org: National Museum of Computing: The Enigma Machine
- YouTube: How did the Enigma Machine work?