3. Onchain Enforcement

Onchain enforcement requires users to submit valid attestations to your smart contract. The contract verifies the attestation before executing protected business logic.

Deploy your contract

Inherit from PredicateClient and set your verification_hash as the policyID.

Add contract to dashboard

Installation

npm i @predicate/contracts

Choose Your Client

Client	Use Case
`BasicPredicateClient`	Who-based policies: AML/KYC, allowlist/denylist, geo-restrictions
`PredicateClient`	Policies that validate function calls, parameters, or value-based limits

Both clients use ERC-7201 namespaced storage for upgrade safety and are audited.

Example Contract

Set your verification_hash from the dashboard as the policyID when deploying.

BasicPredicateClient
PredicateClient

// SPDX-License-Identifier: BUSL-1.1
pragma solidity 0.8.28;

import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
import {BasicPredicateClient} from "@predicate/contracts/src/mixins/BasicPredicateClient.sol";
import {Attestation} from "@predicate/contracts/src/interfaces/IPredicateRegistry.sol";

contract Vault is BasicPredicateClient, Ownable {
    mapping(address => uint256) public balances;

    constructor(
        address _owner,
        address _registry,
        string memory _policyID  // Use your verification_hash here
    ) Ownable(_owner) {
        _initPredicateClient(_registry, _policyID);
    }

    function deposit(Attestation calldata _attestation) external payable {
        require(_authorizeTransaction(_attestation, msg.sender), "Unauthorized");
        balances[msg.sender] += msg.value;
    }

    function setPolicyID(string memory _policyID) external onlyOwner {
        _setPolicyID(_policyID);
    }

    function setRegistry(address _registry) external onlyOwner {
        _setRegistry(_registry);
    }
}

// SPDX-License-Identifier: BUSL-1.1
pragma solidity 0.8.28;

import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
import {PredicateClient} from "@predicate/contracts/src/mixins/PredicateClient.sol";
import {Attestation} from "@predicate/contracts/src/interfaces/IPredicateRegistry.sol";

contract Vault is PredicateClient, Ownable {
    mapping(address => uint256) public balances;

    constructor(
        address _owner,
        address _registry,
        string memory _policyID  // Use your verification_hash here
    ) Ownable(_owner) {
        _initPredicateClient(_registry, _policyID);
    }

    function deposit(
        uint256 _amount,
        Attestation calldata _attestation
    ) external payable {
        bytes memory encodedSigAndArgs = abi.encodeWithSignature(
            "_deposit(uint256)",
            _amount
        );

        require(
            _authorizeTransaction(_attestation, encodedSigAndArgs, msg.sender, msg.value),
            "Unauthorized"
        );

        require(msg.value == _amount, "Incorrect ETH amount");
        balances[msg.sender] += _amount;
    }

    function setPolicyID(string memory _policyID) external onlyOwner {
        _setPolicyID(_policyID);
    }

    function setRegistry(address _registry) external onlyOwner {
        _setRegistry(_registry);
    }
}

Constructor Parameters

Parameter	Description
`_registry`	Predicate Registry address for your chain. See Supported Blockchains.
`_policyID`	Your `verification_hash` from the dashboard

Add Contract to Dashboard

After deploying, add your contract address to your project in the dashboard. This links your contract to your policy configuration.

Solana Program Integration

Predicate provides an Anchor-based program for Solana that handles attestation validation onchain.

Installation

git clone https://github.com/PredicateLabs/sol-contracts
cd sol-contracts
anchor build

Integration Overview

The Solana implementation uses Program Derived Addresses (PDAs) for:

Policy Accounts: Policies associated with program addresses
Attestor Accounts: Registered attestors who can sign attestations
Used UUID Accounts: Replay protection via PDA existence checks

Example Usage

invoke(
    &validate_attestation(
        registry_pda,
        attestor_account,
        policy_account,
        target_program,
        msg_value,
        encoded_instruction_data,
        attestor_key,
        attestation,
    ),
    &[/* accounts */],
)?;

// If validation succeeds, execute business logic

The Solana implementation is in active development and has not yet been audited. Use with caution in production environments.

Resources

Next Steps

Continue to Onchain Integration to update your offchain code.

Essentials

Compliance For

Identity Solution

3. Onchain Enforcement

Installation

Choose Your Client

Example Contract

Constructor Parameters

Add Contract to Dashboard

Solana Program Integration

Installation

Integration Overview

Example Usage

Resources

Next Steps

Essentials

Compliance For

Identity Solution

​Installation

​Choose Your Client

​Example Contract

​Constructor Parameters

​Add Contract to Dashboard

​Solana Program Integration

​Installation

​Integration Overview

​Example Usage

​Resources

​Next Steps

Installation

Choose Your Client

Example Contract

Constructor Parameters

Add Contract to Dashboard

Solana Program Integration

Installation

Integration Overview

Example Usage

Resources

Next Steps