Anthropic's AI model Claude Mythos Preview found mathematical weaknesses in cryptographic algorithms that underpin digital security. According to Anthropic, the model developed an improved attack on the post-quantum signature scheme HAWK and a new attack on a reduced version of the Advanced Encryption Standard (AES). Anthropic says neither finding affects systems in use today. HAWK is only a candidate in an ongoing standardization process run by the U.S. National Institute of Standards and Technology (NIST) and the AES attack applies to a modified version that uses 7 of the full scheme's 10 rounds. Mythos found the HAWK attack in 60 hours for $100,000. Human experts had reviewed HAWK for over two years, but Mythos Preview found an improved attack in just 60 hours, according to Anthropic. The attack exploits a previously undetected symmetry in the mathematical lattice that HAWK's security relies on. Mythos worked semi-autonomously in a multi-agent system to find it. The API costs totaled about $100,000. The model also found the attack on a reduced version of AES-128 almost entirely on its own, according to Anthropic. Mythos then developed a new fingerprinting method that Anthropic calls "Möbius Bridge." The method removes one of the guesses an attacker must make and improves on the best previously known attacks by a factor of 200 to 800. The model initially refused to tackle the problem because it considered further