# ONCHAINID Interface

The ONCHAINID interface defines the set of functions and events used to manage identities and claims on the blockchain. It extends the functionality of two key interfaces: `IERC734` and `IERC735`.

**`isClaimValid`**

**Source**: `IIdentity`

This function checks if a claim is valid based on the identity contract, claim topic, signature, and data provided.

```solidity
function isClaimValid(
    IIdentity _identity,
    uint256 claimTopic,
    bytes calldata sig,
    bytes calldata data
) external view returns (bool);
```

**Description**: Validates a claim by verifying the signature and data against the specified claim topic and identity contract.

***

**`addKey`**

**Source**: `IERC734`

This function adds a key to the identity for a specified purpose and key type.

```solidity
function addKey(bytes32 _key, uint256 _purpose, uint256 _keyType) external returns (bool success);
```

**Description**: Adds a new key to the identity, where `_purpose` defines the purpose of the key (e.g., management or execution), and `_keyType` specifies the type of key (e.g., an Ethereum address or a hash of a public key).

***

**`approve`**

**Source**: `IERC734`

This function approves an execution request.

```solidity
function approve(uint256 _id, bool _approve) external returns (bool success);
```

**Description**: Approves or rejects an execution request identified by `_id`. If approved, the execution proceeds; if not, it is cancelled.

***

**`removeKey`**

**Source**: `IERC734`

This function removes a key for a specified purpose.

```solidity
function removeKey(bytes32 _key, uint256 _purpose) external returns (bool success);
```

**Description**: Removes a key associated with a particular purpose from the identity, effectively revoking its rights.

***

**`execute`**

**Source**: `IERC734`

This function executes an operation on behalf of the identity.

```solidity
function execute(address _to, uint256 _value, bytes calldata _data) external payable returns (uint256 executionId);
```

**Description**: Executes a transaction on behalf of the identity. The `_to` parameter specifies the recipient address, `_value` is the amount of Ether to send, and `_data` contains the call data. Returns an `executionId` for tracking the operation.

***

**`getKey`**

**Source**: `IERC734`

This function retrieves the full data for a specified key.

```solidity
function getKey(bytes32 _key) external view returns (uint256[] memory purposes, uint256 keyType, bytes32 key);
```

**Description**: Returns the purposes, key type, and key value for a specified key. Useful for understanding the roles and permissions associated with a key.

***

**`getKeyPurposes`**

**Source**: `IERC734`

This function returns the list of purposes associated with a key.

```solidity
function getKeyPurposes(bytes32 _key) external view returns (uint256[] memory _purposes);
```

**Description**: Retrieves all purposes assigned to a specified key, providing insight into what the key can be used for.

***

**`getKeysByPurpose`**

**Source**: `IERC734`

This function returns an array of keys associated with a specific purpose.

```solidity
function getKeysByPurpose(uint256 _purpose) external view returns (bytes32[] memory keys);
```

**Description**: Lists all keys that serve a particular purpose, aiding in the management and audit of keys within the identity.

***

**`keyHasPurpose`**

**Source**: `IERC734`

This function checks if a key has a given purpose.

```solidity
function keyHasPurpose(bytes32 _key, uint256 _purpose) external view returns (bool exists);
```

**Description**: Verifies whether a specific key is assigned a particular purpose, returning `true` if it exists and `false` otherwise.

***

**`addClaim`**

**Source**: `IERC735`

This function adds or updates a claim.

```solidity
function addClaim(
    uint256 _topic,
    uint256 _scheme,
    address issuer,
    bytes calldata _signature,
    bytes calldata _data,
    string calldata _uri
) external returns (bytes32 claimRequestId);
```

**Description**: Adds a new claim or updates an existing claim. The claim is associated with a `_topic`, uses a `_scheme` for the signature, and includes the claim's data and URI.

***

**`removeClaim`**

**Source**: `IERC735`

This function removes a claim from the identity.

```solidity
function removeClaim(bytes32 _claimId) external returns (bool success);
```

**Description**: Deletes a claim identified by `_claimId`, revoking the associated attestation.

***

**`getClaim`**

**Source**: `IERC735`

This function retrieves a claim by its ID.

```solidity
function getClaim(bytes32 _claimId)
external view returns(
    uint256 topic,
    uint256 scheme,
    address issuer,
    bytes memory signature,
    bytes memory data,
    string memory uri);
```

**Description**: Returns the full details of a claim, including its topic, scheme, issuer, signature, data, and URI.

***

**`getClaimIdsByTopic`**

**Source**: `IERC735`

This function returns an array of claim IDs for a given topic.

```solidity
function getClaimIdsByTopic(uint256 _topic) external view returns (bytes32[] memory claimIds);
```

**Description**: Lists all claim IDs associated with a specific topic, facilitating the management and audit of claims.