实验吧web-NSCTF web200

题目地址：http://ctf5.shiyanbar.com/web/web200.jpg

一道自编加密函数的题目，只要写个逆向解密的脚本就好了，贴上脚本

$str = "a1zLbgQsCESEIqRLwuQAyMwLyq2L5VwBxqGA3RQAyumZ0tmMvSGM2ZwB4tws";

$str = str_rot13($str);

$str = strrev($str);

$str = base64_decode($str);

$result = '';

for ($i = 0;$i < strlen($str);$i++){

    $temp = substr($str,$i,1);

    $get = ord($temp) - 1;

    $temp = chr($get);

    $result = $result . $temp;

}

$result = strrev($result);

echo $result;

运行

getflag

the end