[AFCTF2018]BASE解题思路

import re,base64
s=open('D:/flag_encode.txt','rb').read()
base16_dic=r'^[A-F0-9=]*&'
base32_dic=r'^[A-Z2-7=]*&'
base16_dic=r'^[A-Za-z0-9/+=]*&'
n=0
while True:
    n+=1
    t=s.decode()
    if'{'in t:
        print(t)
        break
    elif re.match(base16_dic,t):
        s=base64.b16decode(s)
    elif re.match(base32_dic,t):
        s=base64.b32decode(s)
    elif re.match(base64_dic,t):
        s=base64.b64decode(s)