Exchange_Of_prikey_pubkey

Private Key <=> Public Key

1. 了解 `ECDSA`算法

2. secp256k1曲线

比特币和以太坊使用secp256k1定义的椭圆曲线

3. 安装库

1
2
3

npm install ethereumjs-wallet --save
或
npm install ethereumjs-util --save

这两条命令任意执行一条即可

4. 从私钥获取公钥

4.1 方法一

使用 ethereumjs-wallet和 ethereumjs-util

// import Wallet from "ethereumjs-wallet";
// import EthUtil from "ethereumjs-util";

// 因为当前的没指定模块，所以默认使用require语句导入包
var Wallet = require('ethereumjs-wallet').default;
var EthUtil = require('ethereumjs-util');

// Get a wallet instance from a private key
// privatekey
const privateKey = '';
const privateKeyBuffer = EthUtil.toBuffer(privateKey);
const wallet = Wallet.fromPrivateKey(privateKeyBuffer);

// Get a public key
const publicKey = wallet.getPublicKeyString();                                            
console.log(`publicKey is => ${publicKey}`);

4.2 方法二

使用的是ethersjs中的 Waller钱包的publicKey属性获取钱包的公钥，但是获取公钥会在起始位置多出04这个数据段，我暂时还不知道是什么东西

代码：

import { ethers } from "ethers";

// 获取本地的provider
const provider = new ethers.providers.JsonRpcProvider("HTTP://127.0.0.1:8545");

// 根据私钥生成 singer对象
const privateKey = "0x9b139483dc6f6c8782fda2301e9b65a75b3d084d79e79e04c64683bebfa1741d";
const wallet = new ethers.Wallet(privateKey,provider);

// 选择一个私钥
let testPK = privateKey;

// 计算公钥
// const publicKey = curve.keyFromPrivate(testPK).publicKey("hex");
let publicKey = wallet.publicKey;


// 0x607039d2266b689f20e030fdb0033824bcda33bce462ad2504e289f90df96381c363eb4bf5b2c080a56984bdcc8fbd6185053aec487a6fe988bfdef5eba1d55f
// 0x04607039d2266b689f20e030fdb0033824bcda33bce462ad2504e289f90df96381c363eb4bf5b2c080a56984bdcc8fbd6185053aec487a6fe988bfdef5eba1d55f


// let publicKey = "0x04607039d2266b689f20e030fdb0033824bcda33bce462ad2504e289f90df96381c363eb4bf5b2c080a56984bdcc8fbd6185053aec487a6fe988bfdef5eba1d55f";
let newKey = publicKey.substring(0,2) + publicKey.substring(4);
console.log(`newKey = ${newKey}`);

运行结果：

5. 获取以太坊的钱包地址

钱包地址的计算式：

address = address(keccak256(publicKey))

solidity代码：

编译器为0.4版本的

pragma solidity ^0.4.0;

contract publicKey {
    
    // to compute the metamask publicKey
    function getPublicKey1(bytes _publickey) external pure returns (address  _subPublickey) {
        _subPublickey = address(keccak256(_publickey));
        return _subPublickey;
    }
}

编译器为0.8版本的

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

contract publicKey {
    
    // to compute the metamask publicKey
    function getPublicKey1(bytes memory _publickey) external pure returns (address  _subPublickey) {
        _subPublickey = address(uint160(uint256(keccak256(_publickey))));
        return _subPublickey;
    }
}