# Anthropic's Claude Mythos AI Discovers New Cryptographic Weaknesses in HAWK and AES

*2026-07-31 18:01 UTC · AI · 1 min read*

> Anthropic's Claude Mythos Preview model found new mathematical weaknesses in the HAWK and AES cryptographic algorithms, though neither affects deployed systems.

Anthropic disclosed that its Claude Mythos Preview model autonomously discovered previously unknown mathematical weaknesses in two cryptographic algorithms: HAWK, a post-quantum digital signature candidate, and a reduced-round version of AES, the encryption standard securing most of the internet.

Against HAWK, Mythos found a previously unnoticed symmetry in its lattice structure, letting researchers improve the best-known key-recovery attack and effectively cut the scheme's key strength in half — a result that took just 60 hours, despite HAWK having survived two years of expert human review. Against 7-round AES (the full cipher uses 10 rounds), Mythos devised a new fingerprinting technique Anthropic calls "Möbius Bridge," making the best-known attack 200 to 800 times faster by eliminating one of the guesses an attacker must make. Each result cost roughly $100,000 in API usage to produce.

Anthropic emphasized that neither finding threatens deployed systems: HAWK is only a standardization candidate, not yet in production, and the AES attack targets a deliberately weakened research variant, not the full 10-round cipher used in practice. The company says the work shows AI can now contribute original discoveries in theoretical cryptanalysis, a field long dominated by human mathematicians.

## Sources

- [anthropic.com](https://www.anthropic.com/research/discovering-cryptographic-weaknesses)
- [cyberscoop.com](https://cyberscoop.com/anthropic-claude-mythos-encryption-flaws-hawk-aes-pqc/)

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TechTools News · https://techtools.cz/tools/news/article/2107-anthropic-s-claude-mythos-ai-discovers-new-cryptographic-weaknesses-in-hawk-and
Česká verze: https://techtools.cz/tools/news/clanek/2180-ai-model-claude-mythos-od-anthropicu-odhalil-nove-kryptograficke-slabiny-v-hawk