// SPDX-License-Identifier: MIT
pragma solidity ^0.8.13;

contract CommitRevealReceipt {
    mapping(address => bytes32) public commitments;

    event Revealed(address indexed committer, bytes32 receiptHash);

    function commit(bytes32 receiptHash, bytes32 secret) external {
        commitments[msg.sender] = keccak256(abi.encodePacked(uint256(uint160(address(this))), secret, receiptHash));
    }

    function reveal(bytes32 receiptHash, bytes32 secret) external {
        bytes32 commitment = commitments[msg.sender];
        require(commitment != bytes32(0));
        require(keccak256(abi.encodePacked(uint256(uint160(address(this))), secret, receiptHash)) == commitment);
        delete commitments[msg.sender];
        emit Revealed(msg.sender, receiptHash);
    }
}