bugku 蜘蛛侠

bugku 蜘蛛侠

链接

蜘蛛侠

思路

1. 查看hint

2. decode key.jpg

   import os
   
   
   data_jpg = open('file.jpg', 'wb')
   def jpg_encode():
       with open('file.jpg', 'rb') as handle:
           size = os.path.getsize('file.jpg')
           print(size)
           i = 0
           while i<size:
               bytedata = handle.read(1)
               process_data = data_encode(bytedata)
               data_write(process_data)
               i = i + 1
   
   def data_encode(bytedata):
       data = int.from_bytes(bytedata,byteorder='big')
       if (data % 2 == 0):
           data = (data + 1) ^ 128
       else:
           data = (data - 1) ^ 128
       data = bytes([data])
       return data
   
   def data_decode(bytedata):
       data = int.from_bytes(bytedata,byteorder='big')
       if (data % 2 == 0):
           data = (data - 1) ^ 128
       else:
           data = (data + 1) ^ 128
       data = bytes([data])
       return data
   
   def jpg_decode():
       with open('key.jpg', 'rb') as handle:
           size = os.path.getsize('key.jpg')
           print(size)
           i = 0
           while i<size:
               bytedata = handle.read(1)
               process_data = data_encode(bytedata)
               data_write(process_data)
               i = i + 1
   
   
   def data_write(process_data):
       data_jpg.write(process_data)
   
   
   if __name__ == '__main__':
       jpg_decode()
       data_jpg.close()

3. 得到file的jpg

   

4. 010查看发现ffd9后有一串IQ2?kEcY/KK#ojDrHoR'seBbase92编码

5. 解码得到提示silenteye，下载软件解密得到flag