The project is a halo2 verifier written in Move language. Its objective to enhance the capability of the blockchains in the Move ecosystem by enabling halo2 zero-knowledge proofs to be verified on-chain.
Halo2 is a widely used plonk implementation. zcash, scroll, axiom, taiko and many other famous projects are developed based on halo2. There exists a general verification process for different circuits in rust, however, blockchains cannot utilize the code directly because of the gap in the language or api. several organizations are developing onchain verifiers(like halo-solidity-verifier) in solidity for EVM communities, although it’s not a general verifier code, only a general template generator. One still needs to generate a verifier contract for each circuit sharing most of the code.
halo2-verifier.move uses a different approach, it tries to extract the information of a halo2 circuit, and abstract them out into a Protocol of the circuit(we call it the shape of a circuit), circuit’s shape includes:
- Gates. Mainly the constraints you write in the circuit.
- Lookup arguments. include the input expressions and table expressions.
- Queries on each columns.
- Commitments of fixed columns and permutations.
- Other necessary informations like,
k,cs_degree,num_of_fixed_columns.
With these information, the general verifier can read commitments and evaluations in proofs of the circuit, and do verification accordingly using a polynomial commitment scheme.
See TUTORIAL.md.