[WUSTCTF2020]spaceclub

附件是一个txt文件，打开发现是空白的

ctrl+a全选下发现还是有内容的

通过脚本进行替换，长的替换为1，短的替换为0

import binascii
f = open("attachment.txt","r")
content = f.readlines()
s=""
for line in content:
    if len(line)==7:
        s+="0"
    if len(line)==13:
        s+="1"
print(s)
print(binascii.unhexlify(hex(int(s,2))[2:]))

wctf2020{h3re_1s_y0ur_fl@g_s1x_s1x_s1x}