AI Deciphered a 217-Year-Old Coded Letter From Napoleon

• Napoleon Bonaparte’s letter to General Auguste de Marmont remained undeciphered for more than two centuries.
• GPT-6 Astra spent about six hours transcribing the symbols and decrypting the message.
• The letter contains details on the movements and troop numbers of French and Austrian forces on the eve of the 1809 war.

A coded letter sent in 1809 by Eugène Bonaparte, on Napoleon’s instructions, to one of his generals, Auguste de Marmont, has been deciphered with the help of artificial intelligence. The Telegraph reports.

The letter consisted of about 1,300 symbols. Some represented letters, while others stood for archaic words. The cipher needed to decode the message was later lost, so its contents remained unknown for more than two centuries.

Carter Church, an AI engineer at cybersecurity company SentinelOne, said he used OpenAI’s GPT-6 Astra to transcribe and decipher the letter.

According to him, the model spent about six hours working through the symbols and matching them against findings from earlier cryptographers’ research. Before that, specialists had managed to crack 33 symbols in the message.

How did AI decipher the message?

To decrypt it, GPT-6 Astra used a “simulated annealing” technique. It involves testing different word options and comparing the results with Marmont’s already known texts.

Church noted that he had not previously worked on deciphering ciphers. He said he was inspired to try after another case in which AI managed to decrypt an unsolved 1941 German army message.

In that case, technical developer Carter Leffen tasked GPT-6 Astra with finding and decrypting an “Enigma” message. The model completed the task in about 10 hours.

According to The Telegraph, new AI models are showing strong capabilities in solving mathematical problems and decrypting codes. Researchers, however, also fear that such technologies could be used to de-anonymize people online by analyzing their writing style and other identifiers.

What was in Napoleon’s letter?

At the time, Marmont was stationed in what is now Croatia and was cut off from Napoleon’s main forces. The Habsburgs were preparing for war with France to reclaim lost territories.

The letter contained detailed information on the location and troop strength of the French and Austrian forces. Napoleon also ordered the general to prepare for a march and not allow himself to be “intimidated by a few detachments or a rabble gathering.”

“Austria will be attacked immediately from all sides. Therefore, it is rushing toward its demise,” the decrypted message reads.

As a reminder, we previously reported that OpenAI paused the training of new AI models due to agents’ behavior.

Сообщение AI Deciphered a 217-Year-Old Coded Letter From Napoleon появились сначала на INCRYPTED.