<?php
function strcode($str, $passw=""){
$salt = "Dn8*#2n!9j";
$len = strlen($str);
$gamma = '';
$n = $len>100 ? 8 : 2;
while( strlen($gamma)<$len){
$gamma .= substr(pack('H*',sha1($passw.$gamma.$salt)), 0, $n);
}
return $str^$gamma;
}
echo strcode('Hell', '4j');
?>