ZK-EVM

A zero-knowledge virtual machine that generates cryptographic validity proofs for Ethereum-compatible smart contract execution, enabling ZK rollups that run existing Solidity code. Vitalik Buterin's Type 1-4 classification captures the trade-off between full Ethereum equivalence (Type 1, slower proving) and modified execution (Type 4, faster proving). Major implementations include Polygon zkEVM, zkSync Era, Scroll, and Linea.