Discovering cryptographic weaknesses with Claude

This post details how Claude Mythos Preview was used to discover novel mathematical flaws in cryptographic algorithms, specifically an improved attack on the HAWK digital signature scheme and a new attack on round-reduced AES. The HAWK attack reduces the effective keysize by a factor of two by finding a nontrivial automorphism in the lattice, and the AES attack improves the speed of previous best attacks by 200-800x by eliminating a required guess. The research involved semi-autonomous agentic harnesses, extensive literature review, mathematical reasoning, and computational experiments, with a focus on responsible disclosure and collaboration with academic partners to build a cryptanalysis benchmark.