Another factor (according to the excellent Battle of Wits by Budiansky) was that the Germans were overconfident that Enigma was unbreakable. Turned out their c

Another factor (according to the excellent Battle of Wits by Budiansky) was that the Germans were overconfident that Enigma was unbreakable. Turned out their confidence in the hard computation that would need to be done to decode Enigma was wrong.