How did Hans-Thilo Schmidt help break the Enigma cipher?

Hans-Thilo Schmidt was a German spy who sold secret materials about the Enigma machine to the French during World War II. The intelligence he supplied played a crucial role in enabling Polish mathematician Marian Rejewski to reconstruct the wiring inside the Enigma's rotors and reflector. This breakthrough ultimately allowed Allied cryptanalysts to read a vast proportion of encrypted Axis communications.

What we know

• Hans-Thilo Schmidt, codenamed Asché or Source D, was a German spy who sold secrets about the Enigma machine to the French. [2]
• The materials provided by Schmidt facilitated Marian Rejewski's reconstruction of the wiring in the Enigma's rotors and reflector. [2]
• The French-supplied intelligence material obtained from Schmidt was combined with mathematical permutation group theory by Marian Rejewski to break the Enigma cipher in December 1932. [4]

Where to go next

• whoWho was Marian Rejewski?
• how it workedWhat was the cryptologic bomb?
• what followedHow did Bletchley Park use Enigma decrypts?
• compared withWho was Rudolf Schmidt?
• whereWhat was the role of PC Bruno?
• an unexpected connectionHow was a German spy's brother commanding a Panzer army?While Hans-Thilo Schmidt was selling Enigma secrets to the French, his older brother Rudolf Schmidt served as a high-ranking Wehrmacht general on the Eastern Front.

Sources

• [1]Hans-Thilo Schmidt (Wikidata Q67589) · CC0 1.0
• [2]Hans-Thilo Schmidt · CC BY-SA 4.0
• [3]Rudolf Schmidt · CC BY-SA 4.0
• [4]Cryptanalysis of the Enigma · CC BY-SA 4.0
• [5]Enigma machine · CC BY-SA 4.0