Google's AI just mathematically proved Signal's code is secure—a huge leap for software safety.

Google DeepMind's new AlphaProof Code framework has achieved a major milestone in software security: AI agents have mathematically proven key security properties of the actual compiled code behind the widely-used Signal encryption protocol. This marks the first time a widely deployed cryptographic protocol has been formally verified at this depth, using a multi-agent AI system guided by human experts to translate security goals into formal specifications and then generate and audit millions of lines of mathematical proof.

The breakthrough shifts formal verification—the gold standard for proving code runs flawlessly—from being prohibitively labor-intensive for complex systems to a more automated, scalable process. Engineers can now apply these techniques to verify critical software that underpins everything from secure messaging to online banking, focusing human review on the tiny fraction of code where judgment is most needed. This represents a fundamental advance in how we can build and trust the secure systems our digital lives depend on.