GPT-6 Astra Cracks a Century-Old German WWI Radio Cipher

GPT-6 Astra Solves a WWI German Radio Cipher

GPT-6 Astra Cracks a Century-Old German WWI Radio Cipher

GPT-6 Astra decoded a previously unsolved ADFGVX-encrypted German radio message from November 27, 1918, using the key "TRUPPENVERSCHIEBUNG." The plaintext reports an English cruiser arriving at Sevastopol and an Allied squadron following on the 26th. Astra verified the result against HMS Canterbury's logs, which confirm the cruiser reached Sevastopol on November 24, 1918. The key was thought to have entered use only on December 9, 1918, leaving the discrepancy unexplained.

Astra felt compelled to check its work and found that, in fact, the English cruiser HMS Canterbury arrived in Sevastopol on November 24, 1918, based on its original logs.
  1. davidmurdoch

    "You can't hide secrets from the future" - MC Frontalot

  2. iltk

    Can the ships logs be found on the internet? If so, the model could've manufactured a fake key and corresponding message. I think this is unlikely but should probably still be considered.

  3. donatj

    And here I am using it to generate crappy text summaries of work.

  4. sehw

    Or, it found a human that solved it in the dataset and stole the solution.

  5. adverbly

    I'm no crypto expert at all but isn't TRUPPENVERSCHIEBUNG an actual word?

    Google says it translates to "troops shift"

    If so, I don't understand how this was difficult at all... Can't you just do a dictionary attack and then check if the resulting phrase forms a sentence?

    I don't understand how this couldn't be done by someone in their house with access to a computer and a German dictionary.

    Maybe I'm messing something? Was the rearranging of the letters random in some non-deterministic way that wasn't known up front?

  6. justinhj

    That's what I call a Turing test

  7. FabHK

    Isn't that a very simple substitution cipher (any clear text letter is substituted by two letters of cipher text, with a fixed one-to-one correspondence)?

    And aren't they all amenable to very simple cryptanalysis, at least if the encrypted text is long enough, by counting how often certain letters appear, and then trying to plug in reasonable guesses?

    https://en.wikipedia.org/wiki/Substitution_cipher

  8. nojvek

    GPT-9 solves X.

    “Oh GPT-9 found a solved solution on internet and claimed as its own.”

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2026-09-19