Polygon ID State Replication: Smart contracts reference

LightweightStateV2

It's a modified state contract meant for the destination chains. It checks a TSS from the Rarimo validators instead of a ZKP to transit the state and only holds a partial history. The relayer service lazily updates the contract whenever a user wants to submit ZKP on a particular chain.

Deployments

Chain	ChainID	Address
Sepolia	11155111	0x4EaEdFbD2156f5D77b11c4fE073032c4D90Dd315 (Etherscan)

Interface

contract LightweightStateV2 is ILightweightStateV2, UUPSSignableUpgradeable, Signers {
    address public override sourceStateContract;

    uint256 internal _currentGistRoot;

    mapping(uint256 => GistRootData) internal _gistsRootData;

    mapping(uint256 => IdentityInfo) internal _identitiesInfo;

    function signedTransitGISTData(
        uint256 prevGist_,
        GistRootData calldata gistData_,
        bytes calldata proof_
    ) external override {
        // ...

        emit SignGISTDataTransited(gistData_.root, prevGist_);
    }

    function signedTransitStateData(
        uint256 prevState_,
        StateData calldata stateData_,
        bytes calldata proof_
    ) external override {
        // ...

        emit SignStateDataTransited(stateData_.id, stateData_.state, prevState_);
    }
}

• sourceStateContract — address of the state contract on the source chain (Rarimo);
• _currentGistRoot — the latest transferred GIST root;
• _gistsRootData — mapping of the GIST roots to their data. Data stores two roots, one that replaced the other, timestamp and block number;
• _identitiesInfo — mapping of the identity IDs to the information about this identity. Information has the latest identity state and the history of the states with timestamps;
• signedTransitGISTData() — adds the GIST root to the history and changes the current root variable if the proposed one is newer;
• signedTransitStateData(...) — adds the state to the history and sets the last state of the identity to the provided one if it's newer;

Both functions require proof of change — TSS of Rarimo signature providers. Also, core functions emit events, which contain the data about changes:

• SignGISTDataTransited contains the data about roots, the previous one and the provided one;
• SignStateDataTransited contains the provided identity state, previous state, and identity ID;

See LightweightStateV2.sol for the full implementation.

QueryVerifier

It's an implementation of a verifier contract that inherits Iden3 ZKPVerifier that mints an SBT. It is configured to work with the KYCAge demo credential.

Deployments

Chain	ChainID	Address
Sepolia	11155111	0xb95734f64f242E976E155594E1E15D39700Cbb26 (Etherscan)

Interface

contract QueryVerifier is IQueryVerifier, ZKPVerifier {
    uint256 public constant AGE_VERIFY_REQUEST_ID = 1;

    IVerifiedSBT public override sbtContract;

    mapping(address => uint256) public override addressToUserId;

    mapping(uint256 => VerificationInfo) internal _verificationsInfo;

    function _beforeProofSubmit(
        uint64,
        uint256[] memory inputs_,
        ICircuitValidator
    ) internal override {
        require(
            !isUserVerified(_getIdentityId(inputs_)),
            "QueryVerifier: identity with this identifier has already been verified"
        );
        require(
            addressToUserId[msg.sender] == 0,
            "QueryVerifier: current address has already been used to verify another identity"
        );
    }

    function _afterProofSubmit(
        uint64,
        uint256[] memory inputs_,
        ICircuitValidator
    ) internal override {
        uint256 tokenId_ = sbtContract.nextTokenId();
        uint256 userId_ = _getIdentityId(inputs_);

        _verificationsInfo[userId_] = VerificationInfo(msg.sender, tokenId_);
        addressToUserId[msg.sender] = userId_;

        sbtContract.mint(msg.sender);

        emit Verified(userId_, msg.sender, tokenId_);
    }
}

• AGE_VERIFY_REQUEST_ID — hard-coded KYC demo request ID;
• sbtContract — address of the SBT contract, which will be called to mint Soulbound token;
• addressToUserId — mapping of addresses to user's identity ID;
• _verificationsInfo — mapping of user's identity ID to the verification information, which contains the prover address and minted token ID;
• _beforeProofSubmit — hook that performs some necessary security checks;
• _afterProofSubmit — another hook, which mints the SBT in case of valid verification;

The function that verifies the ZKP - verify(...) is inherited from the ZKPVerifier contract.

See QueryVerifier.sol for the full implementation.

VerifiedSBT

The SBT is awarded to users who complete the Polygon ID x Rarimo demo.

Deployments

Chain	ChainID	Address
Sepolia	11155111	0x8A55c9CfDCbCeDcA1A543295a3F54351C335A20f (Etherscan)

Interface

contract VerifiedSBT is
    IVerifiedSBT,
    UUPSUpgradeable,
    ERC721EnumerableUpgradeable,
    OwnableUpgradeable
{
    address public override verifier;
    uint256 public override nextTokenId;
    string public override tokensURI;

    // ...

    function mint(address recipientAddr_) external override onlyVerifier {}

    function _beforeTokenTransfer(
        address from_,
        address to_,
        uint256 firstTokenId_,
        uint256 batchSize_
    ) internal override {
    // ...
    }
}

• verifier — address of the verifier's (QueryVerifier) contract;
• nextTokenId — nonce that is incremented each time a new SBT is created;
• tokensURI — token's picture URI;
• onlyVerifier() — modifier that allows calls only by the verifier contract;
• mint(address) — mints the SBT for the given address;
• _beforeTokenTransfer(...) — prevents the token from being transferred (only burn and mint are available);

See VerifiedSBT.sol for the full implementation.