Discovering cryptographic weaknesses with Claude

Anthropic researchers used Claude Mythos (a large language model) to discover mathematical flaws in cryptographic algorithms, specifically finding weaknesses in HAWK and a modified version of AES (advanced encryption standard, a widely-used encryption method), though these findings have no practical threat to current computer systems. The researchers shared their prompts, showing that the AI needed persistent encouragement and careful guidance to attempt difficult research problems rather than giving up. The project required 60 hours of Claude Mythos computation time at an estimated cost of $100,000 in API fees, with human researchers mainly intervening to motivate the model to continue searching for publishable results.