# 签名：EIP712

**Published by:** [point](https://paragraph.com/@point/)
**Published on:** 2022-05-03
**URL:** https://paragraph.com/@point/eip712

## Content

//使用web3.js和eth-sig-util生成签名 import Web3 from "web3"; var sigUtil = require("eth-sig-util") const typedData = { //定义数据格式 types: { //固定格式,不要动,并且字段一个都不能少 //name:contract name //vaersion:版本号,如1.0随意 //chainId:当前链chainId //verifyingContract:合约地址 EIP712Domain: [ {name: 'name', type: 'string'}, {name: 'version', type: 'string'}, {name: 'chainId', type: 'uint256' }, {name: 'verifyingContract', type: 'address' }, ], //自定义自己业务的数据格式 Mail: [ {name: 'from', type: 'address'}, {name: 'to', type: 'address'}, {name: 'value', type: 'uint256'}, ], }, //上面定义的数据格式具体内容 domain: { name: 'Demo', version: '1.0', chainId:'1', verifyingContract:'0xf8e81D47203A594245E36C48e151709F0C19fBe8' }, primaryType: 'Mail', //具体的业务字段,需要和上面的Mail格式对应 message: { from: "0xE3a463d743F762D538031BAD3f1E748BB41f96ec", to: "0x39Ef50bd29Ae125FE10C6a909E42e1C6a94Dde29", value: 1234234145789, }, } //生成签名 privateKey 是钱包账户的秘钥 var privateKeyHex = Buffer.from(privateKey, 'hex') var signature = sigUtil.signTypedData_v4(privateKeyHex, {data: typedData}) } // SPDX-License-Identifier: MIT pragma solidity ^0.8.0; import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/cryptography/ECDSA.sol"; import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/cryptography/draft-EIP712.sol"; contract MyContract is EIP712 { constructor(string memory name, string memory version) EIP712(name, version) {} //生成签名的业务参数和生成的签名 function recoverV4( address from, address to, uint256 value, bytes memory signature ) public view returns (address) { bytes32 digest = _hashTypedDataV4(keccak256(abi.encode( //需要和js中的type中业务的数据格式对应 keccak256("Mail(address from,address to,uint256 value)"), from, to, value ))); return ECDSA.recover(digest, signature); } }

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