ERC-8262 Reference Implementation

Oracle, verifier router, interfaces, and one circuit for ERC-8262 (Zero-Knowledge Compliance Oracle). Licensed CC0-1.0, except contracts/interfaces/IUltraVerifier.sol, which mirrors the ABI of a Barretenberg-generated verifier and is Apache-2.0.

Layout

contracts/
  ERC8262Oracle.sol           oracle: submission, per-type public-input validation,
                              attestation storage, validation registries
  ERC8262Verifier.sol         router: per-proof-type verifier registry + version history
  interfaces/
    IERC8262Verifier.sol      verifier router interface
    IERC8262Oracle.sol        oracle interface
    IERC165.sol               ERC-165 interface
    IUltraVerifier.sol        per-circuit verifier ABI (Apache-2.0)
  libraries/
    ProofTypes.sol            proof-type IDs + public-input shape validation
    JurisdictionConfig.sol    per-jurisdiction thresholds and signed-signal policy
    AccessControl.sol         GUARDIAN / REGISTRAR / CONFIG roles
    EIP712Attestation.sol     EIP-712 typed-data hashing for attestations
    EIP712CredentialRoot.sol  EIP-712 typed-data hashing for credential roots
    Ownable2Step.sol          two-step ownership transfer
    Pausable.sol              global + per-proof-type pause
circuits/
  compliance/                 COMPLIANCE (0x01) circuit (Noir)
  shared/                     shared Noir crate (hashing, Merkle, ECDSA, risk score)
scripts/
  generate-fixtures.sh        proves each circuit's Prover.toml into test/fixtures/
  patch-pairing-yul.sh        EIP-170 size patch applied to each generated verifier
test/fixtures/<circuit>/      proof + public_inputs for all nine proof types

Where public-input validation lives

The split matters when reading the Public Input Validation section of the standard:

• ProofTypes.validatePublicInputs checks shape only – 32-byte alignment and the expected input count for the proof type.
• ERC8262Oracle._validate*Inputs performs the semantic checks. There is one such function per proof type, each carrying an indexed comment listing every public input at its byte offset, followed by the checks applied to it. Start there when cross-checking the standard against this implementation.

Cross-cutting checks shared by those validators are _assertSubmitter (submitter == msg.sender), _assertResultPositive (the boolean result field is canonical true), _assertValidConfig, _assertConfigNotDenied, _assertChainAndOracleBinding, and _validateProofTimestamp.

The Barretenberg-generated verifier contracts (one ~100 KB Solidity file per proof type) are build artifacts, reproducible from the circuits, and are registered into ERC8262Verifier by address at deploy time.

Proving stack

Circuits are written in Noir – the zero-knowledge domain-specific language for SNARK proving systems, maintained by the Aztec Foundation under a dual MIT / Apache-2.0 license – and compiled to on-chain UltraHonk verifiers by Barretenberg (bb), the optimized bn128 elliptic-curve library and PLONK / UltraHonk proving backend maintained by Aztec Labs under Apache-2.0. Pinned versions:

Build

forge build

cd circuits/compliance && nargo compile
bb write_solidity_verifier -b ./target/compliance.json -o ./compliance_verifier.sol

The COMPLIANCE witness in circuits/compliance/Prover.toml matches the Witness Annex in ERC-8262.

Fixtures

test/fixtures/ holds the binary proof and packed public_inputs for all nine proof types; the Test Cases section of ERC-8262 describes them, and its Witness Annex lists the inputs behind each one.

./scripts/generate-fixtures.sh compliance

re-proves the COMPLIANCE witness, verifies it with bb, writes the fixture, and leaves the named, patched verifier in circuits/compliance/target/. The other eight circuits are not shipped here; place them under circuits/ to regenerate their fixtures. UltraHonk proofs are randomized, so a regenerated proof differs byte-for-byte while public_inputs stays identical.