cryptography

According to testing firm Vals AI, Anthropic's Claude Fable 5.1 independently identified and solved the 'Cyphral Distich,' a 1653 numeric cipher by Sir Thomas Urquhart that had defeated other frontier models. The AI decoded a hidden pro-royalist message by mapping each number to a word in Urquhart's original text.

Anthropic researchers used a Claude model called Mythos Preview to discover new cryptanalytic attacks against the HAWK signature scheme and a weakened version of AES. The work took 60 hours and roughly $100,000 in API costs, with human researchers repeatedly intervening to stop the model from giving up.

Anthropic's Claude Mythos Preview model independently discovered a new cryptanalytic attack on a reduced version of AES-128 and improved an existing attack on the post-quantum signature scheme HAWK. Each research run cost roughly $100,000 in API fees, with human researchers largely limited to project management and verification.