<slide title="Hash with Cookie">
  <example title="Receiving and verifying the cookie"><![CDATA[<?php
list($c_id,$c_hash) = explode('-',$_COOKIE['id']);
if (md5($secret_word.$c_id) == $c_hash) {
    $id = $c_id;
} else {
    die('Invalid cookie.');
}
?>]]></example>
</slide>
