# Engineer reports GPT-6 Astra solved a Napoleonic cipher within six hours

_Published Sunday, October 4, 2026 at 11:06 AM EDT · AI · Latest · Tier 2 — Notable_

![A sample of the ciphered text — Primary](https://cdn.mos.cms.futurecdn.net/7NDTHseunp2EUkVBhZHe5Q-1920-80.jpg)

SentinelOne engineer Carter Church says GPT-6 Astra deciphered a 217-year-old military message within six hours after receiving a single image and prompt. The letter contained 24 rows of numbers, letters and invented symbols and conveyed Napoleon's orders to General Auguste de Marmont.

Church says the model used a partial key previously unconnected with the letter and developed a computational solver to recover the remaining text. He published a solution package with a script that regenerates the reading. Satoshi Tomokiyo, who maintains the Cryptiana historical cipher database, has marked the letter as solved. The result concerns one historical cipher aided by a surviving partial key.

## Sources

- [Tom's Hardware](https://www.tomshardware.com/tech-industry/artificial-intelligence/chatgpt-6-astra-cracks-217-year-old-napoleonic-code-in-just-six-hours-single-prompt-ai-run-solves-24-rows-of-custom-symbols-from-a-single-image-reveals-lost-troop-orders)

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Canonical: https://techandbusiness.org/newswire/_2kCdQJPzg3mEp66bFmkm4
Published: 2026-10-04T15:06:45.146Z
Story chronology: 2026-10-04T13:08:46.000Z
Retrieved: 2026-10-04T17:05:59.514Z
Publisher: Tech & Business (techandbusiness.org)