Python JS逆向篇（二）有道翻译

• 逆向sign参数
• • js实现
  • py实现
• 解密返回结果
• • js实现
  • py未实现
• 实战

逆向主题：有道翻译sign参数及解密返回结果。
（注：文章所涉及内容只做学习参考交流，不做除此之外的任何其它用途！！！）

逆向sign参数

首先，打开浏览器抓包工具，进行页面刷新，全局搜索sign，在资源面板中打开js文件。步骤如下：

开始在页面进行请求，断点 调试数据。

已经拦截到了， 然后就是一步步调式了。
1、进入v(t, e)函数，
2、进入g(e)函数，
3、进入f(e)函数，就进行加密了。

到此，sign参数加密就完成了。如果不知道c.a.createHash(“md5”).update(e.toString()).digest(“hex”)这个算法是怎么实现的，直接复制去百度搜索，不要跟进去一步一步扣代码！！！因为，有现成的js库，直接调用即可。

js实现

import execjs
def get_sign(timestamp):js_code = '''const crypto = require('crypto');const l = 'fanyideskweb',d = 'webfanyi';function g(e) {return crypto.createHash("md5").update(e.toString()).digest("hex")}function v(e, t) {return g(`client=${l}&mysticTime=${e}&product=${d}&key=${t}`)}'''e = 'fsdsogkndfokasodnaso'return execjs.compile(js_code).call('v', timestamp, e)if __name__ == '__main__':print(get_sign(1678674935386))

py实现

import hashlibdef get_sign(timestamp):msg = f'client=fanyideskweb&mysticTime={timestamp}&product=webfanyi&key=fsdsogkndfokasodnaso'return hashlib.md5(msg.encode('utf-8')).hexdigest()if __name__ == '__main__':print(get_sign(1678674935386))

解密返回结果

找到刚刚请求抓到的这个包，然后进去（当然，我这里挨着找的，所以在③处直接就进去了）。

打上断点，发送请求，e.data就是返回加密结果。

单步调试跟进去，如下图：

nn[“a”].decodeData(o, an[“a”].state.text.decodeKey, an[“a”].state.text.decodeIv)

参数o：加密数据
参数an[“a”].state.text.decodeKey和an[“a”].state.text.decodeIv：代码中写死

继续跟进去，这部分代码执行完就得到了最终结果，完成！！！

注意：里面的方法也都是可以由js的crypto解密库所实现，所以也不用自己跟进每个方法里面去扣代码逻辑！如果不知道怎么写js代码，就如同上面所说，直接复制每行代码去问度娘就好！！！

js实现

import subprocess
from functools import partial
subprocess.Popen = partial(subprocess.Popen, encoding="utf-8")
import execjs
# 需要node环境！！！
# 如果执行if分支，则需注意导入包的顺序，这样才能进行定义编码，可能不会报错
# 如果执行else分支，则只需要导入import subprocess即可def decrypt_data(msg, select=True):if select:js_code = '''const crypto = require('crypto');var o = 'ydsecret://query/key/B*RGygVywfNBwpmBaZg*WT7SIOUP2T0C9WHMZN39j^DAdaZhAnxvGcCY6VYFwnHl'var n = 'ydsecret://query/iv/C@lZe2YzHtZ2CYgaXKSVfsb7Y4QWHjITPPZ0nQp87fBeJ!Iv6v^6fvi2WN@bYpJ4'function decrypt_data(t) {const a = crypto.createHash('md5').update(o).digest(), r = crypto.createHash('md5').update(n).digest(), i = crypto.createDecipheriv("aes-128-cbc", a, r);let s = i.update(t, "base64", "utf-8");return s += i.final("utf-8"),s}'''return execjs.compile(js_code).call('decrypt_data', msg)else:return subprocess.Popen(['node', './js实现.js', msg], stdout=subprocess.PIPE).stdout.read()msg = 'Z21kD9ZK1ke6ugku2ccWuwRmpItPkRr5XcmzOgAKD0GcaHTZL9kyNKkN2aYY6yiOmuh9nNfHAP8nmQ1U8cWs8AsPk-qsI0Oi3S_EIBseAYim7wIT81haR5hYOoRK649xgJV2OCWi8mdYBjL3nNw_m22LYYPt_dDmdoFiMiMwddUtdr42g1o9A-MqBEvxSK-H'
print(decrypt_data(msg))

py未实现

实战

import requests, hashlib, time, random
from js实现 import decrypt_dataclass YouDaoFanYi:def __init__(self):self.session = requests.Session()self.headers = {"Accept": "application/json, text/plain, */*","Accept-Language": "zh-CN,zh;q=0.9","Cache-Control": "no-cache","Connection": "keep-alive","Content-Type": "application/x-www-form-urlencoded","Origin": "https://fanyi.youdao.com","Pragma": "no-cache","Referer": "https://fanyi.youdao.com/","Sec-Fetch-Dest": "empty","Sec-Fetch-Mode": "cors","Sec-Fetch-Site": "same-site","User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/110.0.0.0 Safari/537.36","sec-ch-ua": "\"Chromium\";v=\"110\", \"Not A(Brand\";v=\"24\", \"Google Chrome\";v=\"110\"","sec-ch-ua-mobile": "?0","sec-ch-ua-platform": "\"Windows\""}self.get_cookies()def get_cookies(self):try:_ = 2147483647 * random.random()cookies = {"OUTFOX_SEARCH_USER_ID_NCOO": str(_),}response = requests.get(f"https://rlogs.youdao.com/rlog.php?_npid=fanyiweb&_ncat=event"f"&_ncoo={_}&_ntms={str(int(time.time()*1000))}"f"&show=text_translation_result", headers=self.headers, cookies=cookies)self.cookies = {"search-popup-show": "9-7","OUTFOX_SEARCH_USER_ID_NCOO": str(_),"OUTFOX_SEARCH_USER_ID": response.cookies.values()[0]}except Exception as e:raise Exception("cookies获取失败！！！程序退出>>>异常信息：", e)def get_sign(self):msg = f'client=fanyideskweb&mysticTime={self.timestamp}&product=webfanyi&key=fsdsogkndfokasodnaso'return hashlib.md5(msg.encode('utf-8')).hexdigest()def get_data(self):self.timestamp = str(int(time.time()*1000))data = {"i": self.txt,"from": "auto","to": "","domain": "0","dictResult": "true","keyid": "webfanyi","sign": self.get_sign(),"client": "fanyideskweb","product": "webfanyi","appVersion": "1.0.0","vendor": "web","pointParam": "client,mysticTime,product","mysticTime": self.timestamp,"keyfrom": "fanyi.web"}text = self.session.post("https://dict.youdao.com/webtranslate", headers=self.headers,cookies=self.cookies, data=data).textself.res_data = decrypt_data(text)def parse_data(self):print("结果>>>",self.res_data)print()def main(self):while True:self.txt = input("输入要翻译的文本(0退出)：").strip()if self.txt == '0': breakself.get_data()self.parse_data()self.session.close()if __name__ == '__main__':YouDaoFanYi().main()