typed-wx-api/dist/crypto/crypto_common.js

Typed Wechat API

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.WxCrypto = void 0;
const crypto_1 = __importDefault(require("crypto"));
const pkcs7_encode_1 = require("./pkcs7_encode");
/**
 * @internal
 */
class WxCrypto {
    static createNonceStr() {
        return Math.random().toString(36).substr(2, 15);
    }
    static createTimestamp() {
        return new Date().getTime() / 1000 + '';
    }
    constructor(config) {
        this.token = config.token;
        this.id = config.id;
        this.key = new Buffer(config.encodingAESKey + '=', 'base64');
        if (this.key.length !== 32) {
            throw new Error('invalided encodingAESKey');
        }
        this.iv = this.key.slice(0, 16);
    }
    signature(args) {
        const shaSum = crypto_1.default.createHash('sha1');
        const arr = [this.token, args.timestamp, args.nonce, args.encrypt].sort();
        shaSum.update(arr.join(''));
        return shaSum.digest('hex');
    }
    decrypt(text) {
        // 创建解密对象，AES采用CBC模式，数据采用PKCS#7填充；IV初始向量大小为16字节，取AESKey前16字节
        const decipher = crypto_1.default.createDecipheriv('aes-256-cbc', this.key, this.iv);
        decipher.setAutoPadding(false);
        let deciphered = Buffer.concat([
            decipher.update(text, 'base64'),
            decipher.final()
        ]);
        deciphered = pkcs7_encode_1.PKCS7Encoder.decode(deciphered);
        // 算法：AES_Encrypt[random(16B) + msg_len(4B) + msg + $CorpID]
        // 去除16位随机数
        const content = deciphered.slice(16);
        const length = content.slice(0, 4).readUInt32BE(0);
        return {
            message: content.slice(4, length + 4).toString(),
            id: content.slice(length + 4).toString()
        };
    }
    encrypt(text) {
        // 算法：AES_Encrypt[random(16B) + msg_len(4B) + msg + $CorpID]
        // 获取16B的随机字符串
        const randomString = crypto_1.default.pseudoRandomBytes(16);
        const msg = new Buffer(text);
        // 获取4B的内容长度的网络字节序
        const msgLength = new Buffer(4);
        msgLength.writeUInt32BE(msg.length, 0);
        const id = new Buffer(this.id);
        const bufMsg = Buffer.concat([randomString, msgLength, msg, id]);
        // 对明文进行补位操作
        const encoded = pkcs7_encode_1.PKCS7Encoder.encode(bufMsg);
        // 创建加密对象，AES采用CBC模式，数据采用PKCS#7填充；IV初始向量大小为16字节，取AESKey前16字节
        const cipher = crypto_1.default.createCipheriv('aes-256-cbc', this.key, this.iv);
        cipher.setAutoPadding(false);
        const cipheredMsg = Buffer.concat([cipher.update(encoded), cipher.final()]);
        // 返回加密数据的base64编码
        return cipheredMsg.toString('base64');
    }
}
exports.WxCrypto = WxCrypto;
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