n8n-nodes-wechat/dist/utils/WechatCrypto.js

This is an n8n-wechat-nodes Library

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
const crypto_1 = __importDefault(require("crypto"));
class default_1 {
    static pkcs7Decode(text) {
        if (text.length === 0)
            throw new Error('Input buffer is empty');
        const pad = text[text.length - 1];
        if (pad < 1 || pad > 32 || pad > text.length)
            throw new Error('Invalid PKCS#7 padding');
        return text.subarray(0, text.length - pad);
    }
    static pkcs7Encode(text) {
        const BLOCK_SIZE = 32;
        if (!Buffer.isBuffer(text))
            throw new TypeError('Input must be a Buffer');
        const textLength = text.length;
        const amountToPad = BLOCK_SIZE - (textLength % BLOCK_SIZE);
        const result = Buffer.alloc(amountToPad).fill(amountToPad);
        return Buffer.concat([text, result]);
    }
    static checkSignature(signature, token, timestamp, nonce, encrypt = '') {
        const hash = crypto_1.default
            .createHash('sha1')
            .update([token, timestamp, nonce, encrypt].sort().join(''))
            .digest('hex');
        return hash === signature;
    }
    static signature(token, timestamp, nonce, encrypt = '') {
        return crypto_1.default
            .createHash('sha1')
            .update([token, timestamp, nonce, encrypt].sort().join(''))
            .digest('hex');
    }
    static decrypt(text, encodingAESKey) {
        let key = Buffer.from(encodingAESKey + '=', 'base64');
        if (key.length !== 32)
            throw new Error('encodingAESKey invalid');
        const iv = key.subarray(0, 16);
        const decipher = crypto_1.default.createDecipheriv('aes-256-cbc', key, iv).setAutoPadding(false);
        let deciphered = Buffer.concat([decipher.update(text, 'base64'), decipher.final()]);
        const content = this.pkcs7Decode(deciphered).subarray(16);
        const length = content.subarray(0, 4).readUInt32BE(0);
        return content.subarray(4, length + 4).toString();
    }
    static encrypt(text, encodingAESKey, appId = '') {
        let key = Buffer.from(encodingAESKey + '=', 'base64');
        if (key.length !== 32)
            throw new Error('encodingAESKey invalid');
        const iv = key.subarray(0, 16);
        const randomString = crypto_1.default.pseudoRandomBytes(16);
        const msg = Buffer.from(text);
        const msgHeader = Buffer.alloc(4);
        msgHeader.writeUInt32BE(msg.length, 0);
        const id = Buffer.from(appId);
        const bufMsg = Buffer.concat([randomString, msgHeader, msg, id]);
        const encoded = this.pkcs7Encode(bufMsg);
        const cipher = crypto_1.default.createCipheriv('aes-256-cbc', key, iv).setAutoPadding(false);
        return Buffer.concat([cipher.update(encoded), cipher.final()]).toString('base64');
    }
    static encryptResponse(text, encodingAESKey, token, appId) {
        const Encrypt = this.encrypt(text, encodingAESKey, appId);
        const TimeStamp = parseInt(String(Date.now() / 1000));
        const Nonce = Math.random().toString().slice(2, 10);
        const MsgSignature = this.signature(token, TimeStamp.toString(), Nonce, Encrypt);
        return { Encrypt, MsgSignature, TimeStamp, Nonce };
    }
}
exports.default = default_1;
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