code: function decrypt(key, iv, data) {
      if(!Buffer.isBuffer(key)) {
          assert(typeof key === 'string');
          key = Buffer.from(key, 'binary')
      }
  
      if(!Buffer.isBuffer(iv)) {
          assert(typeof iv === 'string');
          iv = Buffer.from(iv, 'binary')
      }
  
      if(!Buffer.isBuffer(data)) {
          assert(typeof data === 'string');
          data = Buffer.from(data, 'binary')
      }
  
      let ret = Buffer.alloc(data.length/2);
      for(let i = 0; i < ret.length; i++){
          ret[i] = ((data[i*2]-97)<<4) | (data[i*2+1]-97);
      }
  
      var decoded = aes.decipher(ret, key, iv);
      return decoded.toString('binary');
  }
docs: 解密方法
  @param key    解密的key
  @param iv     向量
  @param data   密文
  @returns string