Type-2 ZK-EVMs

Architecture

Type-2 ZK-EVMs represent a distinct approach to Ethereum Virtual Machine (EVM) compatibility within zero-knowledge (ZK) rollups, prioritizing separation between execution and proof generation. This architectural divergence contrasts with Type-1 ZK-EVMs, which aim for direct EVM equivalence at the instruction level, and allows for greater flexibility in optimizing for performance and ZK-proof efficiency. Consequently, Type-2 systems often employ a translation step, converting EVM bytecode into an intermediate representation suitable for ZK-proof construction, enabling broader compatibility with existing Ethereum tooling. The design choice impacts the complexity of maintaining EVM equivalence and the potential for gas cost discrepancies between Layer-1 and Layer-2 execution.