Yesterday
@VitalikButerin pushed reference code for SPHINCS- — a post-quantum, hash-based signature scheme built on SHA3/keccak256 and FORS+C counter grinding, designed to be EVM-friendly.
$HASH is already running those exact primitives in production. Browser miners grind nonces against keccak256 challenges, the contract verifies on-chain. Same hash family, same EVM-friendly design, same post-quantum thesis — just applied to issuance instead of signatures.