mattsse/zeth

Zeth is an open-source tool that proves Ethereum and Optimism blockchain blocks are valid, without needing to trust a validator or sync committee. Instead of just claiming that a block was built correctly, Zeth generates a cryptographic proof that anyone can check independently. To do this, Zeth replays every step of block construction inside a special environment called the RISC Zero zkVM (a "zero-knowledge virtual machine"). It fetches block data from a standard RPC provider (like Alchemy) or a local cache, then does the full work of building the block from scratch: verifying signatures, checking account balances, applying transactions, paying rewards, and updating the state. Because all of this happens inside the zkVM, the output is a proof that the block execution was correct. The project offers four modes: build (construct blocks natively without proofs), run (test inside the emulator to measure computation cost), prove (generate a real ZK proof), and verify (check that a proof is valid). You can generate proofs locally on CPU or GPU, or offload the heavy work to Bonsai, RISC Zero's cloud-based proving service. Proofs are saved as files you can verify later. This is most useful for developers or teams working on zero-knowledge proof systems, Layer 2 networks, or anyone who wants to independently verify blockchain state without running a full node. The README notes that Zeth is not audited for production use, so it is currently better suited for experimentation and research than live deployments. It supports Ethereum mainnet and testnets (Sepolia, Holesky) along with Optimism, Base, and their testnets.