encoding function is quite simple and can be directly converted into python code, as follows

-sharp !/usr/bin/python2
-sharp -*- coding: utf-8 -*-
import requests


def get_login_data():
    -sharp 
    url = 'http://xxx.xxx.xxx/Logon.do?method=logon&flag=sess'
    rsp = requests.get(url)
    rsp.raise_for_status()
    return rsp.text.encode()


def encode(usr, pwd, data):
    scode, sxh = data.split('-sharp')
    raw = usr + '%%%' + pwd
    enc = ''
    for i in range(len(raw)):
        if i < 20:
            enc += raw[i] + scode[0:int(sxh[i])]
            scode = scode[int(sxh[i]):]
        else:
            enc += raw[i:]
            break
    return enc


def login():
    -sharp encoded = encode(xx, xx, get_login_data())
    -sharp requests.post(...)
    -sharp ...

if you encounter a very complex encoding (encryption) function, you can extract the javascript code and execute it directly with a js engine (such as nodejs) to get the result.

the encoded I see is to get a string by requesting the interface / Logon.do?method=logon&flag=sess , then the first half is the string that needs to be mixed, and the second half is the mixed length, and then the string is stitched together with the user name and password to cross-mix to get the final encoded
CAPTCHA you need to identify the picture

it is you who are protected.