An Enigma cipher that the German military failed to crack for 85 years was deciphered by GPT-6 Astra in 10 hours.

Beating AI News Flash: A Bloomberg product developer, Carter Leffen, used GPT-6 Astra to crack a 1941 German Enigma ciphertext. He himself is not a cryptographer.

The ciphertext was only 82 letters long and had previously been listed by the cipher history website CryptoCellar as unbroken. Astra Extra High took about 10 hours to find the answer.

The key clue came from another telegram from the same day that had already been deciphered. Astra noticed that the place name "ROSENOW" appeared twice in succession in it, and then guessed that this word was also hidden in the target ciphertext. It then wrote an Enigma simulator and search program, tested different keys in parallel, and then used the original telegram header and the remaining text for verification.

The final recovered content was very simple: "Please inform march route. I am at Rosenow. Please reply immediately by radio."

However, this time it was not entirely done by Astra alone. Leffen was responsible for setting the goal and advancing the investigation, while Astra completed a large amount of research, coding, search execution, and verification work.