Google DeepMind AlphaProof Code Formally Verifies Signal Protocol Cryptography
On November 10, 2026, Google DeepMind utilized its agentic AlphaProof Code framework, hosted on the Carbon platform, to achieve formal verification of the libsignal cryptographic library. The process mathematically proved the security properties of the Signal Protocol—specifically post-quantum handshakes and the Triple Ratchet mechanism—down to the compiled machine code level. By generating approximately 6.5 million lines of Lean proof scripts, this effort closes the critical assurance gap between cryptographic specifications and deployed binaries. This confirms that the implementation is mathematically resilient against transient key exposure, ensuring that forward secrecy and key-compromise resilience are maintained during actual execution.