According to Scienceblogs.de, a German science blogging portal maintains a list of 50 unsolved ciphers, including a set of German radio messages from World War I encoded using the ADFGVX method.
The ADFGVX cipher system works by arranging letters and numbers in a grid labeled with the letters A, D, F, G, V, and X on both axes. Each character in a message is encoded using a pair of these letters corresponding to its position in the grid. The encryption key determines how the grid is arranged. For example, using “HOUSE” as the key would produce one arrangement, while “TRUPPENVERSCHIEBUNG” produces a completely different grid.
According to the source text, over a dozen of these German radio messages have remained unsolved despite efforts by codebreaking experts including George Lasry. One particular message, transmitted on November 27, 1918, had eluded decryption for years.
GPT-6 Astra, an AI model, successfully decoded this cipher. The decrypted message reads: “AN ENGLISH CRUISER ARRIVED AT SEVASTOPOL ON THE ?4TH AN ALLIED SQUADRON FOLLOWS ON THE 26TH.” The model determined that “TRUPPENVERSCHIEBUNG” was the encryption key used for this message.
According to the source, Astra proposed that this message remained unsolved because “TRUPPENVERSCHIEBUNG” was documented as being used as the encryption key starting December 9, 1918—after this message was transmitted on November 27. The reason for this discrepancy is unknown.
To verify its solution, Astra cross-referenced historical records and found that HMS Canterbury, an English cruiser, arrived in Sevastopol on November 24, 1918, according to its original logs. Historical records also confirm that an allied squadron arrived on November 26, matching the decoded message’s claim about the 26th.
The source indicates this is believed to be the first successful decoding of this particular message, demonstrating capabilities of the AI model in solving complex historical cryptography problems.
Key facts
- GPT-6 Astra decoded a German ADFGVX cipher from a radio message transmitted November 27, 1918
- The decrypted message reported an English cruiser arriving in Sevastopol and an allied squadron following on the 26th
- The encryption key used was ‘TRUPPENVERSCHIEBUNG’
- This message had previously eluded decryption efforts despite known encryption keys
- Historical logs confirm HMS Canterbury arrived in Sevastopol on November 24, 1918, and an allied squadron arrived November 26