Bugku-PHP_encrypt_1

这是题目给的代码，还有返回值fR4aHWwuFCYYVydFRxMqHhhCKBseH1dbFygrRxIWJ1UYFhotFjA=

1. # -*- coding: UTF-8 -*-
   
2. import base64
   
3. # import hashlib
   
4. 
   
5. '''
   
6. def eccrypt(data):
   
7.     key = hashlib.md5('ISCC').hexdigest()
   
8.     # print 'key-->', key
   
9.     x = 0
   
10.     char = ''
    
11.     data_len = len(data)  # data的长度
    
12.     key_len = len(key)  # key的长度
    
13.     for i in range(data_len):
    
14.         if x == key_len:
    
15.             x = 0
    
16.         char += key[x]
    
17.         x += 1
    
18.     # print 'char-->', char
    
19.     flag = ''
    
20.     for i in range(data_len):
    
21.         flag += chr((ord(data[i]))+(ord(char[i])) % 128)
    
22.     # print 'flag-->', flag
    
23.     return base64.b64encode(flag)
    
24. '''
    
25. 
    
26. 
    
27. def detrcy(b64):
    
28.     int_b64 = []
    
29.     b64de = base64.b64decode(b64)
    
30.     # print 'b64de-->', b64de
    
31.     # print 'len_b64de-->', len(b64de)
    
32.     for i in range(len(b64de)):
    
33.         int_b64.append(ord(b64de[i]))
    
34.     # print 'int_b64-->',int_b64
    
35.     # print 'len_int_b64-->', len(int_b64)
    
36.     key = '729623334f0aa2784a1599fd374c120d729623'  # 知道data的长度后直接写出来
    
37.     int_key = []
    
38.     for i in range(len(key)):
    
39.         int_key.append(ord(key[i]))
    
40.     # print 'int_key-->', int_key
    
41.     flag = ''
    
42.     for i in range(len(int_b64)):
    
43.         flag += chr((int_b64[i]-int_key[i]+128) % 128)
    
44.     print flag
    
45. 
    
46. 
    
47. if __name__ == '__main__':
    
48.     # str_b64 = eccrypt('XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX')
    
49.     # print 'str_b64-->', str_b64
    
50.     str_b64 = 'fR4aHWwuFCYYVydFRxMqHhhCKBseH1dbFygrRxIWJ1UYFhotFjA='
    
51.     # print 'str_b64-->', str_b64
    
52.     detrcy(str_b64)
    

复制代码

解密的代码，得到flag