title: Generate UUID for transactions - keeps giving wrong input
body: <p>I am creating an online enrollment form. When a user advances to page 2, I generate a 'unique' ID for that user with the following PHP command:</p>
  
  <pre><code>$_SESSION['ConfirmationNo'] = rand(100000000, 999999999);
  </code></pre>
  
  <p>however, later in the process, when a user can actually view their confirm number, they can simply 'refresh' the page once and a new confirmation number will appear. </p>
  
  <p>Any way to do this where that particular ID is locked down from page 1 or 2?</p>
  
  <p>Thanks!</p>