Ed25519应用，node，js生成经常使用的密钥对

Ed25519签名算法介绍

Ed25519做者

Daniel J. Bernstein 是世界著名的密码学家

优点

彻底开放设计，算法各个参数直接了当，明确，很大的几率经过缓存、时间、恶意输入摧毁安全性，而 25519 系列椭圆曲线通过特别设计，尽量的将出错的几率降到了最低，25519 系列曲线是目前最快的椭圆曲线加密算法，一个4核2.4GHz 的 Westmere cpu，每秒能够验证 71000 个签名，吊打同类：椭圆曲线是 NIST

基本特色

公共钥只有32字节，私钥只有64字节

实战node，js生成Ed25519密钥对

目标

经过tweetnacl生成原始的Uint8Array密钥对，生成公钥，私钥类型首字母G,S写入Buffer，而后私钥写入Buffer，经过上面Buffer计算校验码再次写入buffer，最后使用base32编码。生成用户常规保存的字符串。

首先安装依赖包

npm I tweetnacl crc lodash base32.js —save
解释简单解释说明下包的做用
tweetnacl： 最核心的包,是用javascript接口实现的TweetNaci/Naci端口，它实现了密钥加密解密，公钥验证加密，公共签名，hash等。咱们将使用这个库生成，原始的Uint8Array密钥对。也能够本身随机一个64byte私钥，而后解析为keypair。
crc：生成校验码的
lodash:是一个一致性、模块化、高性能的 JavaScript 实用工具库。
base32.js：因为原生方法，只有base64，因此引入base32.js进行编码解码

具体代码实现

//各类引入  
const nacl = require(“tweetnacl");
const crc = require("crc");
const base32 = require("base32.js")
const isUndefined = require("lodash/isUndefined");
const isNull = require("lodash/isNull");
const isString = require("lodash/isString");
const versionBytes = {
  ed25519PublicKey:  6 << 3, // G
  ed25519SecretSeed: 18 << 3, // S
  preAuthTx:         19 << 3, // T
  sha256Hash:        23 << 3  // X
};

//封装一个类，构造函数中生成keypair，提供静态编码解码公钥私钥方法
class Keypair {
    constructor(){
        this.orikeypair = nacl.sign.keyPair();
        this.publicKey = Buffer.from(this.orikeypair.publicKey);
        console.log(this.orikeypair.publicKey);
        this.privateKey = Buffer.from(this.orikeypair.secretKey);
    }
    static encodeCheck(versionByteName, data) {
        if (isNull(data) || isUndefined(data)) {
            throw new Error("cannot encode null data");
        }
        let versionByte = versionBytes[versionByteName];
        if (isUndefined(versionByte)) {
            throw new Error(`${versionByteName} is not a valid version byte name.  expected one of "ed25519PublicKey", "ed25519SecretSeed", "preAuthTx", "sha256Hash"`);
        }
        data  = Buffer.from(data);
        let versionBuffer = Buffer.from([versionByte]);
        let payload       = Buffer.concat([versionBuffer, data]);
        let checksum      = calculateChecksum(payload);
        let unencoded     = Buffer.concat([payload, checksum]);
        return base32.encode(unencoded);
    }
    static decodeCheck(versionByteName, encoded) {
        if (!isString(encoded)) {
          throw new TypeError('encoded argument must be of type String');
        }
        let decoded     = base32.decode(encoded);
        let versionByte = decoded[0];
        let payload     = decoded.slice(0, -2);
        let data        = payload.slice(1);
        let checksum    = decoded.slice(-2);
        if (encoded != base32.encode(decoded)) {
          throw new Error('invalid encoded string');
        }
        let expectedVersion = versionBytes[versionByteName];
        if (isUndefined(expectedVersion)) {
          throw new Error(`${versionByteName} is not a valid version byte name.  expected one of "accountId" or "seed"`);
        }
        if (versionByte !== expectedVersion) {
          throw new Error(`invalid version byte. expected ${expectedVersion}, got ${versionByte}`);
        }
        let expectedChecksum = calculateChecksum(payload);
        if (!verifyChecksum(expectedChecksum, checksum)) {
          throw new Error(`invalid checksum`);
        }
        return Buffer.from(data);
    } 
}
function calculateChecksum(payload) {
  // This code calculates CRC16-XModem checksum of payload
  // and returns it as Buffer in little-endian order.
  let checksum = Buffer.alloc(2);
  checksum.writeUInt16LE(crc.crc16xmodem(payload), 0);
  return checksum;
}
//测试使用
let newKeypair = new Keypair();
console.log(newKeypair.publicKey);
let newPublic = Keypair.encodeCheck("ed25519PublicKey",newKeypair.publicKey);
let newPrivate = Keypair.encodeCheck("ed25519SecretSeed",newKeypair.privateKey);
let publicBuffer = Keypair.decodeCheck("ed25519PublicKey",newPublic);
console.log(newPublic,newPrivate);
console.log(publicBuffer);

说明

相关包的详细api能够直接复制包名字在github查找