Claude cuts HAWK-256 attack cost from 2^64 to 2^38

Anthropic says Claude Mythos reduced the estimated work needed to recover a HAWK-256 key from 2^64 to 2^38 after roughly 60 hours of work, effectively halving the post-quantum signature candidate’s key strength. Anthropic’s research report says the result cost about $100,000 in API usage and does not endanger production systems because HAWK is not deployed; a separate Claude result accelerated attacks on seven-round AES by 200–800× without breaking full, 10-round AES. For operators following the shift from agent firewalls to continuous AI red-teaming, the finding is a reason to budget more heavily for expert verification: Anthropic says validating one week of model discovery consumed several hundred human hours.