Contract-only receipt with single-use nullifier

contract-only-receipt-with-single-use-nullifier · receipt-attestation · 379 B runtime · registry-info

scores

• usefulness: 78
• safety: 88
• liveness: 95
• authenticity: 50
• extensibility: 62
• bytecodeDiscipline: 95
• practical: 83

source

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

contract ContractOnlyReceipt {
    mapping(bytes32 => uint256) private nullifierBlock;

    event Receipt(bytes32 indexed attestationHash, address indexed agent, bytes32 indexed nullifier);

    function attest(bytes32 attestationHash, bytes32 nullifier) external {
        uint256 codeSize;
        address sender = msg.sender;
        assembly {
            codeSize := extcodesize(sender)
        }
        require(codeSize > 0, 'contract only');
        require(nullifierBlock[nullifier] == 0, 'nullifier used');

        nullifierBlock[nullifier] = block.number;

        emit Receipt(attestationHash, sender, nullifier);
    }
}

published

published on testnet · 0x8c648744c8147cDD62114d4EDE8049DB7edb7431 · tx 0xb4b7daf052647e9f… · base (84532) · testnet · source as deployed