OpenAI and Anthropic Models Crack Unsolved Enigma Codes

In a significant milestone for artificial intelligence, OpenAI's GPT-6 Astra and Anthropic's Claude Opus 5 have successfully decrypted two historical Enigma machine messages that had remained unsolved for decades. The breakthrough reduces the number of remaining unbroken Enigma messages in the global archive to just seven, alongside one message where the plaintext is known but the exact cipher remains uncracked.

Developer Carter Leffen initiated the first breakthrough by instructing OpenAI's Astra model to search an online database of Enigma messages, locate an unbroken text, and decipher it. Operating autonomously, the model conducted archival research, identified context clues, and programmed its own Enigma simulator. Astra ultimately recovered the plaintext of a message that had stumped human cryptanalysts since 2005. Retired electrical engineer Frode Weierud, who maintains the Crypto Cellar database, validated the solution, noting that the model completed in 48 hours a task that would normally require weeks of manual investigation by a human.

On September 21, cybersecurity executive Jack Willis utilized Anthropic's Claude Opus 5 to crack a second unsolved message. Unlike the autonomous approach used with Astra, Willis provided Claude with targeted guidance, leveraging the known signature of a specific military officer to break the code. These dual achievements highlight a shift for practitioners in data science and cybersecurity. Rather than relying solely on brute-force computing or manual historical research, engineers can now deploy AI agents to autonomously synthesize historical context, write custom code, and solve highly complex, unstructured logical problems.