[安洵杯 2019]easy misc 1

打开题目

 掩码爆破

计算出来是7

 爆破完

 decode.zip的解压码是2019456NNULLULL, 是一张替换表

 小姐姐.PNG，foremost分离

 两张差不多的图，可能是盲水印

python bwmforpy3.py decode 00000000.png 00000232.png 1.png --oldseed，提示11.txt

https://github.com/chishaxie/BlindWaterMark

hint.txt打开乱码，用notepad++的ASCII编码

 字频统计

跑个大佬脚本

# -*- coding:utf-8 -*-
#Author: mochu7
alphabet = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890!@#$%^&*()_+- =\\{\\}[]"
strings = open('./11.txt').read()
 
result = {}
for i in alphabet:
    counts = strings.count(i)
    i = '{0}'.format(i)
    result[i] = counts
 
res = sorted(result.items(),key=lambda item:item[1],reverse=True)
for data in res:
    print(data)
 
for i in res:
    flag = str(i[0])
    print(flag[0],end="")

etaonrhisdluygwm

跟统计表进行对照

QW8obWdIWT9pMkFSQWtRQjVfXiE/WSFTajBtcw==

base64解码

 base85解码