Proof of Humanity smart contracts reference

To make the Proof of Humanity verification result easily re-usable and to enable easy integration with existing DApps like quest platforms, each verified user gets a soulbound token(SBT).

This is facilitated by the smart contracts described below.

VerifiedSBT

The SBT awarded to users who complete the Proof of Humanity verification.

Deployments

Chain	ChainID	Address
Polygon	137	0xaD7De01cb7eaAFf3a419A0a0a3133a964cD90373 (Polygonscan)
Goerli	5	0xfaA7e7F14a2dCAD537d0141533bB58D62dD8022c (Etherscan)

Interface

contract VerifiedSBT is
    IVerifiedSBT,
    UUPSUpgradeable,
    ERC721EnumerableUpgradeable,
    OwnableUpgradeable
{
    // ...

    address public override verifier;
    uint256 public override nextTokenId;
    string public override tokensURI;

    modifier onlyVerifier() {
        require(msg.sender == verifier, "VerifiedSBT: only verifier can call this function");
        _;
    }

    function mint(address recipientAddr_) external override onlyVerifier {
        _mint(recipientAddr_, nextTokenId++);
    }

    // ...
}

• verifier - address of the verifier's (SBTIdentityVerifier) contract;
• nextTokenId - nonce that is incremented each time a new SBT is created;
• tokensURI - token's picture URI;
• onlyVerifier() - modifier that only allows calls by the verifier contract;
• mint(address) - mints the SBT for the given address;

See VerifiedSBT.sol for the full implementation.

SBTIdentityVerifier

It's an implementation of a verifier contract that mints a Proof of Humanity SBT when a correct proof is provided.

Deployments

Chain	ChainID	Address
Polygon	137	0x7DdAde70efADf832A600ba483FAD26fCA477FE2A (Polygonscan)
Goerli	5	0x86906AbAAfA7F58Fb4D3125BD1971Fcf04F52CDd (Etherscan)

Interface

contract SBTIdentityVerifier is ISBTIdentityVerifier, BaseVerifier {
    function _proveIdentity(ProveIdentityParams calldata proveIdentityParams_) internal {
        _verify(SBT_IDENTITY_PROOF_QUERY_ID, proveIdentityParams_);

        require(
            addressToIdentityId[msg.sender] == 0,
            "IdentityVerifier: Msg sender address has already been used to prove the another identity."
        );

        IQueryValidator queryValidator_ = IQueryValidator(
            zkpQueriesStorage.getQueryValidator(SBT_IDENTITY_PROOF_QUERY_ID)
        );

        uint256 identityId_ = proveIdentityParams_.inputs[queryValidator_.getUserIdIndex()];

        require(
            !isIdentityProved(identityId_),
            "IdentityVerifier: Identity has already been proven."
        );

        uint256 newTokenId_ = sbtToken.nextTokenId();
        sbtToken.mint(msg.sender);

        addressToIdentityId[msg.sender] = identityId_;
        _identitiesProofInfo[identityId_] = SBTIdentityProofInfo(msg.sender, newTokenId_, true);

        emit SBTIdentityProved(identityId_, msg.sender, address(sbtToken), newTokenId_);
    }
}

• _proveIdentity(...) checks the validity for a ZKP and mints an SBT;

See SBTIdentityVerifier.sol for the full implementation.