An artificial intelligence model autonomously resolved a cryptographic puzzle from the second World War that had remained a mystery for decades. The system broke a German Army message sent via an Enigma machine by searching historical archives and constructing its own simulator to test competing keys. It wrote original cryptanalysis code and ran parallel experiments to recover the plaintext before cross-checking the results.

The achievement by GPT-6 Astra occurred Sept. 15 and involved the identification of contextual clues and the comparison of uncertain letters. The model performed the research and decryption without human intervention to unlock the 1941 communication, applying a sequence of agentic steps that include the creation of a simulator to verify plaintext.