加密解密

某NS的NPC事件加密解密

HASH_DATA // 255位的hash
KEY       // 反编译得到的key

import * as crypto from 'crypto';

const HASH_DATA = Array.from({ length: 255 }, (_, i) => i);
const KEY = HASH_DATA.map((val) => String.fromCharCode(val)).join('');
const KEY_BYTES_DATA = Buffer.from(KEY, 'hex');
const IV = Buffer.alloc(8);

class NpcDataParser {
  static fixDataLen(data: string, num: number = 8): Buffer {
    const paddingStr = Buffer.alloc(1, 0x00);
    const fixData = Buffer.from(data, 'binary');
    const paddingLength = num - (fixData.length % num);
    return Buffer.concat([fixData, paddingStr.repeat(paddingLength)]);
  }

  static calculateHash(data: string): [number, number] {
    let resultData = 0;
    const decryptedData = this.fixDataLen(data, 8).toString('binary');

    for (let i = 0; i < decryptedData.length; i++) {
      resultData = HASH_DATA[(resultData & 0xFF) ^ decryptedData.charCodeAt(i)] ^ (resultData >>> 8);
    }

    return [resultData & 0xFF, resultData >>> 8];
  }

  static encodeData(data: string): Buffer {
    try {
      const keyIndexEn0 = Buffer.alloc(1, 0x00);
      const bytesIndex = keyIndexEn0.readUIntLE(0, 1) * 8;
      const keyEn = KEY_BYTES_DATA.slice(bytesIndex, bytesIndex + 8);
      const crpytor = crypto.createCipheriv('des', keyEn, IV);
      const fixData = this.fixDataLen(data, 8);

      const [byte1, byte2] = this.calculateHash(data);
      const byte1Buffer = Buffer.alloc(1);
      byte1Buffer.writeUIntLE(byte1, 0, 1);
      const byte2Buffer = Buffer.alloc(1);
      byte2Buffer.writeUIntLE(byte2, 0, 1);

      const encryptData = Buffer.concat([keyIndexEn0, byte1Buffer, byte2Buffer, crpytor.update(fixData)]);
      return encryptData;
    } catch (e) {
      console.error('加密数据失败: ', e);
      return Buffer.alloc(0);
    }
  }

  static decodeData(data: Buffer): string {
    try {
      const keyIndexDe = data.readUIntLE(0, 1);
      const bytesIndex = keyIndexDe * 8;
      const keyDecode = KEY_BYTES_DATA.slice(bytesIndex, bytesIndex + 8);
      const crpytor = crypto.createDecipheriv('des', keyDecode, IV);
      const decryptData = crpytor.update(data.slice(3));
      return this.fixDataLen(decryptData.toString('binary')).toString('utf8');
    } catch (e) {
      console.error('解密数据失败: ', e);
      return '';
    }
  }
}

const npcParser = new NpcDataParser();

if (require.main === module) {
  // 使用
  // 从数据库中读取
  // const data = "xxxxxx";
  // NpcDataParser.encodeData(data);
  npcParser.decodeData(Buffer.from('12312', 'hex'));
}