html = sess.get(LOGIN_PAGE).text
execution = re.search(r'name="execution" value="(.*?)"', html).group(1)

var reversed = password.split('').reverse().join('');
var key = RSAUtils.getKeyPair(exp, '', mod);
var cipher = RSAUtils.encryptedString(key, reversed);

import math

def js_style_rsa(pwd, mod_hex, exp_hex):
    rev = pwd[::-1].encode()
    n, e = int(mod_hex, 16), int(exp_hex, 16)
    chunk = 2 * (math.ceil(n.bit_length()/16) - 1)

    buf = bytearray(rev)
    while len(buf) % chunk:
        buf.append(0)

    return ' '.join(
        format(pow(int.from_bytes(buf[i:i+chunk], 'little'), e, n), 'x')
        for i in range(0, len(buf), chunk)
    )

form = {
    'username': user,
    'password': js_style_rsa(pwd, pub['modulus'], pub['exponent']),
    'authcode': '',
    'execution': execution,
    '_eventId': 'submit'
}
resp = sess.post(LOGIN_PAGE, data=form, allow_redirects=False)

redirect_url = resp.headers['Location']
sess.get(redirect_url, allow_redirects=True)
auth = sess.cookies.get('AUTHORIZATION')
print('AUTHORIZATION =', auth)

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""cas_login.py —— 通用 CAS 登录脚本示例（域名已脱敏）"""
import requests, re, math
from getpass import getpass

LOGIN_PAGE = (
    'https://auth.example.edu.cn/cas/login'
    '?service=https://learning.example.edu.cn/api/fromcas'
)
PUBKEY_API = 'https://auth.example.edu.cn/cas/v2/getPubKey'

def js_style_rsa(pwd, mod, exp):
    rev = pwd[::-1].encode()
    n, e = int(mod, 16), int(exp, 16)
    chunk = 2 * (math.ceil(n.bit_length()/16) - 1)
    buf = bytearray(rev)
    while len(buf) % chunk:
        buf.append(0)
    return ' '.join(format(pow(int.from_bytes(buf[i:i+chunk], 'little'), e, n), 'x')
                    for i in range(0, len(buf), chunk))

def main():
    user = input('学号 / 用户名: ').strip()
    pwd  = getpass('密码（输入时不回显）: ')

    s = requests.Session()
    s.headers['User-Agent'] = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64)'

    html = s.get(LOGIN_PAGE).text
    execution = re.search(r'name="execution" value="(.*?)"', html).group(1)

    pub = s.get(PUBKEY_API).json()
    enc = js_style_rsa(pwd, pub['modulus'], pub['exponent'])

    data = {'username': user, 'password': enc, 'authcode': '',
            'execution': execution, '_eventId': 'submit'}
    r = s.post(LOGIN_PAGE, data=data, allow_redirects=False)
    if 'Location' not in r.headers:
        print('登录失败')
        return

    s.get(r.headers['Location'], allow_redirects=True)
    print('✅ AUTHORIZATION =', s.cookies.get('AUTHORIZATION'))

if __name__ == '__main__':
    main()