# Ethereum线下签名实现

**Published by:** [puhahaha](https://paragraph.com/@puhahaha/)
**Published on:** 2023-11-09
**URL:** https://paragraph.com/@puhahaha/ethereum

## Content

步骤创建并打包原始消息 原始消息：”Hello, Web3.” 消息哈希：0xb0a90a95a2e95f53bc8a27629ce3d3b8c32507b1889e418e308b4ecb0d01554c生成以太坊签名哈希 签名哈希：0x8eea87c68554dc0b647493d38a4b53aeea63c6841b10290714ff5f65ff08f2d5Metamask签名消息 打开浏览器前端console，输入 ethereum.send('eth_requestAccounts') account = "以太坊签名账户地址" hash = "消息哈希" ethereum.request({method: "personal_sign", params: [account, hash]}) 得到签名： 0x7ac68849793e559e457718a22f0b122ec3f9c94ed2a5163283d6a55d3c3c32c05e2eaeaa81766fe6c6ce82e971f66a943a7dfa34a9f3d40ede2fb66ea4d698b01c验签 使用签名地址、以太坊签名哈希、签名，验签代码// SPDX-License-Identifier: GPL-3.0 pragma solidity >=0.8.2 <0.9.0; contract test { function getMessageHash(string memory message) public pure returns(bytes32) { return keccak256(abi.encodePacked(message)); } function getEthSignedMessageHash(bytes32 _messageHash) public pure returns(bytes32) { return keccak256( // 这是标准字符串: \x19Ethereum Signed Message:\n // 32 表示后面的哈希内容长度 abi.encodePacked("\x19Ethereum Signed Message:\n32", _messageHash) ); } function recoverSigner(bytes32 _ethSignedMessageHash, bytes memory _signature) public pure returns (address) { (bytes32 r, bytes32 s, uint8 v) = splitSignature(_signature); // 返回解析出来的签名地址 return ecrecover(_ethSignedMessageHash, v, r, s); } // 分割签名 function splitSignature(bytes memory sig) public pure returns(bytes32 r, bytes32 s, uint8 v) { require(sig.length == 65, "invalid signature length"); // 通过读取内存数据 根据规则进行截取 返回 r, s, v 数据 assembly { r := mload(add(sig, 32)) s := mload(add(sig, 64)) v := byte(0, mload(add(sig, 96))) } } function verify(bytes32 _ethSignedMessageHash, bytes memory _signature, address _signer) public pure returns(bool) { return recoverSigner(_ethSignedMessageHash, _signature) == _signer; } }

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