WorkJuly 28, 2026via Simon Willison

Discovering cryptographic weaknesses with Claude

Why it matters

AI models are now actively discovering real security vulnerabilities in cryptographic systems—a shift from theoretical capability to production-grade threat detection that fundamentally changes how organizations approach cryptography auditing and vulnerability disclosure.

Key signals

  • Claude used for cryptographic weakness discovery
  • Real-world application of LLM reasoning to security research
  • Implications for vulnerability disclosure and responsible AI use
  • Published by Simon Willison (credible AI researcher/observer)
  • Date: July 28, 2026 (recent/breaking)
  • Claude discovered cryptographic weaknesses
  • Demonstrates AI capability in security research domain
  • Raises responsible disclosure and dual-use concerns
  • Published July 28, 2026 on Simon Willison's platform (credible technical source)
  • Practical security implications for enterprise cryptography

The hook

Claude just found cryptographic flaws humans missed. Here's why your security team needs to care.

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