Ethereum’s leanVM clears formal verification in its push toward quantum resistance

The minimal zkVM behind Ethereum's post-quantum signature plan is now formally verified end to end, with a December 2028 target for the full transition Ethereum just checked off one of the less glamorous but more important boxes on its quantum defense roadmap. Ethereum Foundation researcher Justin Drake announced on November 3, 2026 that leanVM has achieved end-to-end formal verification. leanVM is the tool designed to make post-quantum signatures practical at network scale. The project sits at the center of an effort to harden Ethereum against quantum threats across all three layers of the protocol.