[攻防世界]web2

<?php
$miwen="a1zLbgQsCESEIqRLwuQAyMwLyq2L5VwBxqGA3RQAyumZ0tmMvSGM2ZwB4tws";function encode($str){$_o=strrev($str);//字节反转// echo $_o;for($_0=0;$_0<strlen($_o);$_0++){$_c=substr($_o,$_0,1);//取出$_o每个字符$__=ord($_c)+1;//返回ASC码+1$_c=chr($__);//相当于向后$_=$_.$_c;   } return str_rot13(strrev(base64_encode($_)));
}highlight_file(__FILE__);
/*逆向加密算法，解密$miwen就是flag */
?>

依次逆向解密即可

• rot13
• 字符串逆置
• base64
• 字符串向前移位还原1
• 字符串逆置

得出flag

• flag:{NSCTF_b73d5adfb819c64603d7237fa0d52977}