AI Agents Finally Made Formal Verification Practical — and Signal's Core Code Is the Proof

Google DeepMind announced on November 10, 2026 that its agentic framework, AlphaProof Code, has produced the first machine-checked mathematical proofs connecting high-level security guarantees to the unmodified, compiled code of a widely used cryptographic protocol implementation: Signal's libsignal. A five-person research team, working with teams of autonomous AI agents , completed the proof work in roughly four weeks — a task the researchers say historically would have demanded decades of manual effort. Understanding Formal Verification and AlphaProof Code Formal verification is the practice of proving, mathematically, that a piece of software satisfies specified properties — not merely testing it against anticipated inputs, but establishing a logical guarantee that holds for all cases. As DeepMind's researchers Pushmeet Kohli and Swarat Chaudhuri note, today's assurance comes primarily from testing, bug finding, and code review, and real bugs often sit in the gap between a…