John Davidson

Message:

 function decode($encoded, $key)

 {

        $strofsym = "qwertyuiopasdfghjklzxcvbnm1234567890QWERTYUIOPASDFGHJKLZXCVBNM="; 

        $x = 0;

        while ($x++<= strlen($strofsym))

        {

            $tmp = md5(md5($key.$strofsym[$x-1]).$key);

            $encoded = str_replace($tmp[3].$tmp[6].$tmp[1].$tmp[2], 

            $strofsym[$x-1], $encoded);

        }

        return base64_decode($encoded);

 }

when switching to PHP 8 I get the following error. on PHP 7.2 works well.
Warning: Undefined array key 63 in line 7 and 8
HElp me, please.

---

My Answer:
substr($encoded, 0, 63);
$decoded = '';
for ($i = 63; $i < strlen($encoded); $i++) {
$decoded .= $encoded[$i] ^ $key[$i % strlen($key)];
}
return $decoded;
}