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This page covers the SDK methods and contract functions used to register, link, and manage user identity data with Newton.

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SDK Methods

The following methods are available on the wallet client actions extension (newtonWalletClientActions).

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registerUserData

Registers KYC data for a user, scoped to your application’s identity domain. Opens the Newton identity popup to securely store the data. Signature: 
registerUserData(args: {
  userData: KycUserData
  appIdentityDomain: Hex
}): Promise<unknown>
Parameters:
ParameterTypeDescription
userDataKycUserDataKYC data object from your identity vendor
appIdentityDomainHexYour identity domain as a bytes32 hex string (keccak256 of your domain string)
Example: 
await walletClient.registerUserData({
  userData: kycDataFromVendor,
  appIdentityDomain: '0xabc123...', // keccak256(bytes("my.dev.domain.co"))
})

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linkApp

Links a user’s registered identity to your policy client contract. The user must confirm the link in the Newton identity popup, which triggers a signed transaction from their wallet. Signature: 
linkApp(args: {
  appWalletAddress: Address
  appClientAddress: Address
  appIdentityDomain: Hex
}): Promise<unknown>
Parameters:
ParameterTypeDescription
appWalletAddressAddressThe user’s dapp wallet address
appClientAddressAddressYour deployed policy client contract address
appIdentityDomainHexYour identity domain as a bytes32 hex string
Example: 
await walletClient.linkApp({
  appWalletAddress: '0xUserWallet...',
  appClientAddress: '0xYourPolicyClient...',
  appIdentityDomain: '0xabc123...',
})

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unlinkApp

Removes a user’s identity link from your policy client contract. Signature: 
unlinkApp(args: {
  appWalletAddress: Address
  appClientAddress: Address
  appIdentityDomain: Hex
}): Promise<unknown>
Parameters:
ParameterTypeDescription
appWalletAddressAddressThe user’s dapp wallet address
appClientAddressAddressYour deployed policy client contract address
appIdentityDomainHexYour identity domain as a bytes32 hex string
Example: 
await walletClient.unlinkApp({
  appWalletAddress: '0xUserWallet...',
  appClientAddress: '0xYourPolicyClient...',
  appIdentityDomain: '0xabc123...',
})

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Contract Functions

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linkIdentityAsUser

Called on the IdentityRegistry contract to link a user’s identity to a policy client. This is invoked under the hood when the user confirms the link via linkApp. See Contract Addresses for the IdentityRegistry address. Signature: 
function linkIdentityAsUser(
    address _identityOwner,
    address _policyClient,
    bytes32[] calldata _identityDomains,
    bytes calldata _signature,
    uint256 _nonce,
    uint256 _deadline
)
Parameters: The following are the output of the link SDK method.
ParameterTypeDescription
_identityOwneraddressThe identity owner being used to authorize access to the existing identity
_policyClientaddressThe policy client where the data is to be associated
_identityDomainsbytes32[]The identity domains specifying what type of data is associated
_signaturebytesSignature by the _identityOwner to authorize the link
_nonceuint256Nonce for the signature
_deadlineuint256Deadline for the signature

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Sample Policy Client

Your policy client contract must inherit both NewtonPolicyClient and EIP712. Below is a complete example: 
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.27;

import {NewtonPolicyClient} from "newton-contracts/src/mixins/NewtonPolicyClient.sol";
import {INewtonProverTaskManager} from "newton-contracts/src/interfaces/INewtonProverTaskManager.sol";
import {EIP712} from "@openzeppelin/contracts/utils/cryptography/EIP712.sol";

contract NewtonPolicyWallet is NewtonPolicyClient, EIP712 {
    event Executed(address indexed to, uint256 value, bytes data, bytes32 taskId);
    error InvalidAttestation();
    error ExecutionFailed();

    constructor(
        address policyTaskManager,
        address owner
    ) EIP712("NewtonPolicyWallet", "1") {
        _initNewtonPolicyClient(policyTaskManager, owner);
    }

    function supportsInterface(bytes4 interfaceId) public view override returns (bool) {
        return interfaceId == 0xdbdcaa9c || super.supportsInterface(interfaceId);
    }

    function validateAndExecuteDirect(
        address to,
        uint256 value,
        bytes calldata data,
        INewtonProverTaskManager.Task calldata task,
        INewtonProverTaskManager.TaskResponse calldata taskResponse,
        bytes calldata signatureData
    ) external returns (bytes memory) {
        require(
            _validateAttestationDirect(task, taskResponse, signatureData),
            InvalidAttestation()
        );

        (bool success, bytes memory result) = to.call{value: value}(data);
        if (!success) revert ExecutionFailed();

        emit Executed(to, value, data, task.taskId);
        return result;
    }

    receive() external payable {}
}
After deploying, register this contract with the PolicyClientRegistry. See Smart Contract Integration for instructions.

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Next Steps

Identity Policy Reference

Rego built-in functions for writing identity-aware policies

Contract Addresses

IdentityRegistry and other deployed contract addresses