LLMs Break Cryptographic Schemes in New CryptanalysisBench Study
A new benchmark, CryptanalysisBench, demonstrates that frontier LLMs can perform meaningful cryptanalysis, breaking 65–86% of schemes with known practical vulnerabilities and producing novel attacks against previously unbroken primitives. Anthropic's Mythos Preview model uncovered new vulnerabilities in the Hawk signature scheme and reduced-round AES, representing the first AI-discovered cryptanalytic results of this kind. This signals a near-term shift in the threat landscape where AI-assisted cryptanalysis may begin to outpace human expert analysis.