A claim has emerged that artificial intelligence (AI) has deciphered a cipher that remained unsolved for 373 years,El.kz cites Chosun.
This has been praised as demonstrating AI’s potential to resolve problems that would otherwise require humans to spend extensive time sifting through materials and testing countless hypotheses. However, counterarguments arose immediately after the announcement, asserting that the decryption could not be replicated using the original source material.
AI evaluation firm Vals AI stated on the 1st (local time) that it had identified a solution to the 1653 cipher “Cyphral Distich,” left by Scottish writer Thomas Urquhart, using Anthropic’s newly released AI model “Claude Fable 5.1.”
The cipher consists of two lines of 32 numbers each, totaling 64 digits. It appears in Urquhart’s 1653 book *Logopandecteision* and was reprinted in an 1834 compilation of his works. Multiple attempts to decode it since the late 19th century have failed, and it was included in cryptographer Klaus Schmeh’s list of “50 Unsolved Ciphers.”
During pre-release performance testing of Claude Fable 5.1, Vals AI assigned the problem to the AI without human intervention. After approximately 44 minutes and processing 176,000 tokens, the AI identified a clue in the number “32.” It noted that the cipher immediately follows Urquhart’s “Proquiritations,” a list of 32 petitions, and that each line of the cipher also contains 32 numbers.
Vals AI’s published decryption method involves linking the first number to the first petition, the second to the second, and so on. By taking the first letter of the word indicated by each number, the 64 digits reportedly form the sentence: “O GOD UPHOLD KING CHARLES THE SECOND AND MAKE HIM THE SUPREME RULER OF THIS LAND.” This aligns with Urquhart’s known royalist political leanings.
However, the same day, an analysis questioning the result was posted on the AI community platform “The Colony.” The author, after reviewing the 1653 original held by the British Library, pointed out that the two-line numerical cipher described by Vals AI does not appear after the 32nd petition. Instead, the original text continues with decorative elements, Latin phrases, and a closing statement.
Vals AI explained, “While humans would need to manually search through old materials and test multiple decryption methods over long periods, AI can rapidly iterate these tasks—a significant advantage.”
