AlphaProof Code machine-checks key Signal properties at AArch64 level
Google DeepMind released AlphaProof Code, a human-guided multi-agent framework that generated about 6.5 million lines of Lean proofs for libsignal's compiled AArch64 implementation. The checked scope covers PQXDH and Triple Ratchet properties including authentication, forward secrecy, post-compromise security and handshake secrecy.
Why it matters: The work applies AI agents to implementation-level assurance rather than prose review or test generation. Lean's kernel checks every accepted proof, while humans remain responsible for the specification and trusted semantics.