The GPT-6 Astra artificial intelligence system deciphered a secret military message from 1809, written on Napoleon’s orders. It took just six hours.
The letter was sent to one of the generals on the eve of the war with Austria. The AI examined an old scan, found a partial key to the cipher in historical sources, and reconstructed the values of the remaining symbols. Cryptographer Satoshi Tomokiyo checked the result.
The message listed the positions of the French and allied armies and also advised the general not to fear the enemy’s superior forces. Although the letter yielded no sensational discoveries, the case shows how AI can help historians crack old ciphers and find connections between archival documents.
