GPT-6 Astra Deciphers an Undeciphered 1918 German WWI Radio Message—And Verifies Its Own Work

GregKamradt · x · 2026-09-18

deredleritt3r reports that GPT-6 Astra deciphered a 1918 German radio transmission that, to his knowledge, had never been broken. The message reads: "An English cruiser arrived at Sevastopol on the ?4th; an allied squadron follows on the 26th."

More striking, the model double-checked its own work: it verified that HMS Canterbury reported arriving at Sevastopol on November 24, 1918, with an allied squadron following on the 26th. The message is one of 20 WWI German radio messages on a public cipher challenge list that had resisted decryption.

GregKamradt adds a takeaway: a side effect of more capable AI is a better understanding of which problems are actually interesting—many open puzzles may simply be waiting for a model to try.

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