Smart Contracts

Reference for Proof of Humanity V2 smart contracts, covering the IProofOfHumanity interface, identity queries, and registration lifecycle functions.

Core Interface

The IProofOfHumanity interface exposes the functions needed to query and interact with the PoH V2 registry.

Identity Queries

/// @dev Returns true if the address is registered as a verified human.
/// Checks both V2 registrations and V1 via Fork Module.
function isHuman(address _account) external view returns (bool);

/// @dev Returns the humanityId bound to an address.
/// Returns bytes20(0) if the address is not registered.
function humanityOf(address _account) external view returns (bytes20);

/// @dev Returns the address currently bound to a humanityId.
/// Returns address(0) if the humanityId is not claimed.
function boundTo(bytes20 _humanityId) external view returns (address);

/// @dev Returns true if the humanityId is currently claimed by any address.
function isClaimed(bytes20 _humanityId) external view returns (bool);

Registration Functions

/// @dev Submits a new registration claim.
/// Requires payment of the registration deposit.
function claimHumanity(bytes20 _humanityId, string calldata _evidence) external payable;

/// @dev Vouches for a pending registration.
/// Voucher must be a registered human.
function vouch(address _claimer, bytes20 _humanityId) external;

/// @dev Challenges a pending or existing registration.
/// Creates a dispute in Kleros Court.
function challengeRequest(
    bytes20 _humanityId,
    uint256 _reason,
    string calldata _evidence
) external payable;

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Cross-Chain Interface

The ICrossChainProofOfHumanity contract mirrors identity state on foreign chains. It exposes the same read functions:

interface ICrossChainProofOfHumanity {
    function isHuman(address _account) external view returns (bool);
    function isClaimed(bytes20 _humanityId) external view returns (bool);
    function humanityOf(address _account) external view returns (bytes20);
    function boundTo(bytes20 _humanityId) external view returns (address);
}

State updates are propagated from the home chain (Gnosis) to foreign chains through bridge transactions.

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Data Structures

Humanity

Each registered human is represented by a Humanity struct containing the registration state:

Field	Type	Description
owner	address	Current wallet address bound to this humanity
humanityId	bytes20	Unique soulbound identifier
expirationTime	uint40	When the registration expires and requires renewal
nbPendingRequests	uint256	Number of active registration or renewal claims

Challenge Reasons

Challenges must specify a reason code:

Code	Reason	Description
0	None	Invalid
1	IncorrectSubmission	Profile does not meet registration policy requirements
2	Deceased	The registered human is deceased
3	Duplicate	The submitter is already registered under a different humanityId
4	DoesNotExist	The submitter does not exist or the video is fabricated

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Events

/// @dev Emitted when a new registration claim is submitted.
event ClaimRequest(address indexed _requester, bytes20 indexed _humanityId);

/// @dev Emitted when a claim is challenged.
event ChallengePeriodRestart(
    bytes20 indexed _humanityId,
    uint256 indexed _requestId,
    uint256 _challengeId
);

/// @dev Emitted when a registration is confirmed after the challenge period.
event HumanityClaimed(bytes20 indexed _humanityId, address indexed _owner);

/// @dev Emitted when a registered human is removed (revocation or expiry).
event HumanityRevoked(bytes20 indexed _humanityId, address indexed _owner);

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Dispute Integration

When a registration is challenged, PoH creates a dispute in Kleros Court with the following parameters:

Parameter	Value
Arbitrator	KlerosCore on the home chain
Court	Humanity Court (courtId configured at deployment)
Choices	2 (Accept Registration / Reject Registration)
Ruling 0	Refuse to arbitrate
Ruling 1	Accept -> registration is valid
Ruling 2	Reject -> registration is invalid

Evidence is submitted on-chain and displayed in the Court V2 interface. The dispute template specifies the PoH registration policy as the primary document for juror evaluation.