📌 GPT-6 Astra Deciphered a Letter From the Napoleonic Era
On March 16, 1809, as France prepared for war with Austria, Napoleon ordered his stepson, Eugène de Beauharnais, Viceroy of Italy, to send General Auguste de Marmont an encrypted report detailing the positions of French and allied armies.
The full key did not survive, so the letter remained unread for 217 years-until engineer Carter Church recently came across it. He had never broken a cipher before, but decided to try with AI. His only source was a low-quality scan from a 1969 French military journal: 24 lines of handwritten numbers, letters, and special symbols.
Astra split the image into lines, recognized the symbols, grouped different handwriting variants into 155 distinct signs, and wrote a program to recover the key. The letter contained 1,300 elements in total.
The model did not start from scratch. Cryptography historian Daniel Tant had previously identified the values of 33 symbols, enough to read about one-third of the letter. Astra helped recover the remaining two-thirds.
One part of the report said that "the Russians are marching against Austria." Other letters from Napoleon suggest he had no evidence that this was true: the emperor himself had ordered such information to be spread even though he did not know where the Russian troops were.
🔍 Church spent several evenings on the project, while Astra ran for about six hours in total. According to the engineer, a specialist could have solved the cipher as early as 1970-but it would have taken weeks.
@hiaimediaen
On March 16, 1809, as France prepared for war with Austria, Napoleon ordered his stepson, Eugène de Beauharnais, Viceroy of Italy, to send General Auguste de Marmont an encrypted report detailing the positions of French and allied armies.
The full key did not survive, so the letter remained unread for 217 years-until engineer Carter Church recently came across it. He had never broken a cipher before, but decided to try with AI. His only source was a low-quality scan from a 1969 French military journal: 24 lines of handwritten numbers, letters, and special symbols.
Astra split the image into lines, recognized the symbols, grouped different handwriting variants into 155 distinct signs, and wrote a program to recover the key. The letter contained 1,300 elements in total.
The model did not start from scratch. Cryptography historian Daniel Tant had previously identified the values of 33 symbols, enough to read about one-third of the letter. Astra helped recover the remaining two-thirds.
The full text of the letter:
To General Marmont, from the Viceroy's headquarters, late March 1809
[These letters] contained the orders and instructions that [His Majesty] had charged me with conveying to you. Today I hasten to inform you of the positions of the French and allied armies. The Duke of Danzig, at the head of 40,000 Bavarians, occupies Munich and Passau. Prince Poniatowski, at the head of 30,000 Poles, is encamped on the Vistula, threatening Kraków. The Prince of Pontecorvo commands the Saxon army encamped before Dresden, while the Duke of Auerstädt occupies Bayreuth with 80,000 French troops. The Duke of Rivoli commands 60,000 men quartered in Ulm and Donauwörth. [General] Oudinot, with an elite corps of 40,000 men, is in Augsburg and along the Lech.
The Russians are marching against Austria, and the army [in] Friuli now numbers 80,000 men. Add the Dalmatian corps, not counting the reserves being formed everywhere in the rear, and you will see that Austria will be attacked simultaneously from all sides. It is therefore rushing toward its destruction. When you receive the order to march, you must not allow yourself to be intimidated by a few troops or a gathering of rabble.
I am still eagerly awaiting news from you. The Austrians remain in Ljubljana, Klagenfurt, Villach, and Salzburg and appear to threaten Tyrol through Lienz. However, one might think that they intend to send troops into Galicia to oppose the Russians. This disposition suggests that their campaign plan has already been disrupted before war has even been declared. Nothing is certain yet, however. The militia has been called into active service, and although efforts have been made to stir up the population, it has not yet been shown that these levies will significantly strengthen the army.
One part of the report said that "the Russians are marching against Austria." Other letters from Napoleon suggest he had no evidence that this was true: the emperor himself had ordered such information to be spread even though he did not know where the Russian troops were.
🔍 Church spent several evenings on the project, while Astra ran for about six hours in total. According to the engineer, a specialist could have solved the cipher as early as 1970-but it would have taken weeks.
@hiaimediaen