Anthropic's Claude Weakens HAWK Post-Quantum Signature Candidate, Reduces Key Strength to 2^38 in 60 Hours

According to Anthropic, the Claude Mythos Preview model discovered an improved attack method against HAWK, a post-quantum digital signature candidate developed by NIST to counter quantum computing threats, on July 29. The attack reduced HAWK-256's effective key strength from 2^64 to 2^38 in just 60 hours, substantially lowering the theoretical cost of cryptanalysis. HAWK has not been deployed in production systems, so the attack poses no immediate threat to existing infrastructure.

The 60-hour HAWK attack cost approximately $100,000 in API expenses and was completed with minimal cryptographer guidance. Claude independently conducted literature reviews, mathematical reasoning, and experimental validation. Anthropic researchers subsequently spent hundreds of hours verifying the results.