天下武功唯快不破 

解題連結： http://ctf5.shiyanbar.com/web/10/10.php 

#!/usr/bin/python
# -*- coding:utf8 -

import requests
import base64
url = 'http://ctf5.shiyanbar.com/web/10/10.php'
re = requests.get(url) #請求url
key = re.headers['FLAG'] #獲得響應頭中的FLAG值
key = base64.b64decode(key) #base64解碼key
s = ':'
key = key[key.find(s)+1:] #分割key值，提取flag值。[+1:]從:到最後
#key = key.split(':')[1]
re = requests.post(url,data={"key":key})#傳送帶有key的post值
print(re.text)