# Google DeepMind uses AI agents to formally verify Signal's cryptographic protocol code

> Original title: Introducing AlphaProof Code: a breakthrough in verifying complex software at depth

- Source: Google DeepMind
- Published: 2026-11-10T12:02:28.000Z
- Bad Influence: https://badinfluence.news/items/c088nvrwqa1kizb3u4iou9thp
- Original: https://deepmind.google/blog/introducing-alphaproof-code/

## Summary

Google DeepMind says researchers used its AlphaProof Code agentic framework to mathematically prove key security properties of the code underlying the Signal protocol. The agents generated over six million lines of Lean and flagged about one percent of the codebase for human review, and the work took four weeks. The team also says it open-sourced its formal verification artifacts.

## Why it matters

The source details how AI agents, checked by Lean, verified a deployed protocol's implementation code, not only its design, giving a concrete model for formal verification workflows.