title: How are codeigniter's session system separated with PHP's built in $_SESSION?
body: <p>As the manual says:</p>
  
  <blockquote>
    <p>Note: The Session class does not utilize native PHP sessions. It
    generates its own session data, offering more flexibility for
    developers.</p>
  </blockquote>
  
  <p>But when I store some data using <code>$this-&gt;session-&gt;set_userdata(array('sample_key' =&gt; 'sample_value'));</code>, in <code>phpinfo()</code> I can find <code>sample_key</code> and <code>sample_value</code> in that.</p>
  
  <p>I hoped that the part </p>
  
  <blockquote>
    <p>does not utilize native PHP sessions</p>
  </blockquote>
  
  <p>to be meaning that it hides the session variables from <code>phpinfo()</code>.</p>
  
  <p>I'd always thought that it might be a security lack. Could it be?</p>
  
  <p>As it seems, the values are <code>urlencode</code>ed.</p>