題目連結

https://learn.cylabacademy.org/library/240

題目解法

下載腳本並執行後可以發現在第 20 行的地方報錯。

1
2
3
4

$ python fixme1.py 
  File "/home/kali/workspace/fixme1.py", line 20
    print('That is correct! Here\'s your flag: ' + flag)
IndentationError: unexpected indent

使用 nano 或其他習慣的文字編輯器編輯檔案，將第 20 行最開頭的兩個空格刪除。

nano fixme2.py

要退出 nano 要按下 Ctrl + X，接著按下 Y，再按下 Enter 即可退出。 退出後再次執行 python 腳本即可得到 flag。

$ python fixme1.py
That is correct! Here's your flag: picoCTF{1nd-------------------c8f}

題目原始碼

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21


import random



def str_xor(secret, key):
    #extend key to secret length
    new_key = key
    i = 0
    while len(new_key) < len(secret):
        new_key = new_key + key[i]
        i = (i + 1) % len(key)        
    return "".join([chr(ord(secret_c) ^ ord(new_key_c)) for (secret_c,new_key_c) in zip(secret,new_key)])


flag_enc = chr(0x15) + chr(0x07) + chr(0x08) + chr(0x06) + chr(0x27) + chr(0x21) + chr(0x23) + chr(0x15) + chr(0x5a) + chr(0x07) + chr(0x00) + chr(0x46) + chr(0x0b) + chr(0x1a) + chr(0x5a) + chr(0x1d) + chr(0x1d) + chr(0x2a) + chr(0x06) + chr(0x1c) + chr(0x5a) + chr(0x5c) + chr(0x55) + chr(0x40) + chr(0x3a) + chr(0x58) + chr(0x0a) + chr(0x5d) + chr(0x53) + chr(0x43) + chr(0x06) + chr(0x56) + chr(0x0d) + chr(0x14)

  
flag = str_xor(flag_enc, 'enkidu')
  print('That is correct! Here\'s your flag: ' + flag)