前言：

　　這題跟python有關，可見看懂python程式碼還是很有必要得，需要有一些python基礎才好

easychallenge：

　題目： 下載後來發現是一個.pyc為字尾得檔案，查詢資料可知，該檔案為python編譯後得檔案，所以我們第一步應該是反編譯，將其轉成py檔案

我們使用python得uncompyle6庫來進行反編譯，安裝出錯或者太慢試試這個，

 pip install -i https://pypi.doubanio.com/simple/ 包名

下面給出如何使用得命令

uncompyle6  -o  F:\桌面\  F:\桌面\tmp\1.pyc

然後將反編譯後得py檔案內容給出：

 1 # uncompyle6 version 3.7.3
 2 # Python bytecode 2.7 (62211)
 3 # Decompiled from: Python 3.8.5 (tags/v3.8.5:580fbb0, Jul 20 2020, 15:43:08) [MSC v.1926 32 bit (Intel)]
 4 # Embedded file name: ans.py
 5 # Compiled at: 2018-08-09 11:29:44
 6 import base64
 7 
 8 def encode1(ans):
 9     s = ''
10     for i in
 
 ans:
11         x = ord(i) ^ 36
12         x = x + 25
13         s += chr(x)
14 
15     return s
16 
17 
18 def encode2(ans):
19     s = ''
20     for i in ans:
21         x = ord(i) + 36
22         x = x ^ 36
23         s += chr(x)
24 
25     return s
26 
27 
28 def encode3(ans):
29     return base64.b32encode(ans)
 
30 
31 
32 flag = ' '
33 print 'Please Input your flag:'
34 flag = raw_input()
35 final = 'UC7KOWVXWVNKNIC2XCXKHKK2W5NLBKNOUOSK3LNNVWW3E==='
36 if encode3(encode2(encode1(flag))) == final:
37     print 'correct'
38 else:
39     print 'wrong'

可以看到通過該py檔案加密後得final是UC7KOWVXWVNKNIC2XCXKHKK2W5NLBKNOUOSK3LNNVWW3E=== ，然後我們修改一下encode3 encode2 encode1，將其改成decode1 decode2 decode3,

下面給出程式碼：

 1 # uncompyle6 version 3.7.3
 2 # Python bytecode 2.7 (62211)
 3 # Decompiled from: Python 3.8.5 (tags/v3.8.5:580fbb0, Jul 20 2020, 15:43:08) [MSC v.1926 32 bit (Intel)]
 4 # Embedded file name: ans.py
 5 # Compiled at: 2018-08-09 11:29:44
 6 import base64
 7 
 8 def decode3(ans):
 9     s = ''
10     for i in ans:
11 #        x = ord(i) ^ 36
12 #        x = x + 25
13         
14         x = ord(i) -25
15         x = x ^ 36
16         s += chr(x)
17 
18     return s
19 
20 
21 def decode2(ans):
22     s = ''
23     for i in ans:
24 #        x = ord(i) + 36
25 #        x = x ^ 36
26         
27         x = i ^ 36
28         x = x - 36
29         s += chr(x)
30 
31     return s
32 
33 
34 def decode1(ans):
35     return base64.b32decode(ans)
36 
37 
38 final = b'UC7KOWVXWVNKNIC2XCXKHKK2W5NLBKNOUOSK3LNNVWW3E==='
39 print(decode3(decode2(decode1(final))))

反向即可解碼

參考連結：

https://www.runoob.com/python3/python3-func-ord.html