Bloomberg Developer Uses GPT-6 Astra to Crack 83-Year-Old Enigma Code

A Bloomberg developer claims to have cracked a German military radio message encrypted with an Enigma machine that had gone unbroken for over 80 years, using OpenAI's GPT-6 Astra. The 82-character telegram was sent in 1941 by a German soldier requesting marching route instructions.

Carter Leffen, a product development coach at Bloomberg LP in New York, said the "Extra High" version of GPT-6 Astra spent about 10 hours on the problem, handling everything from searching historical archives and building an Enigma simulator to writing cryptanalysis code, testing different keys, and cross-verifying results.

The breakthrough came from the place name "Rosenow," which appeared twice in another already-decrypted message from the same day. Combined with the Enigma machine's known weakness of never encrypting a letter as itself, the team quickly ruled out many possible positions and recovered coherent German text including "Sofort Funkantwort" (immediate radio reply) and "Angabe des Marschweges" (specify marching route).

The project page now offers all code, search data, and a working 3D Enigma simulator for download, though the decryption still needs further independent expert review.