title: How to encode strings inside serial number using PHP?
body: <p>I need to generate serial numbers using PHP in the following format "ASDK3-JDAL9-24SFT-J5D8R-D4AL9". One requirement is the fact that I need to encode somehow a timestamp and an email address inside this serial number and then retrieve them when needed. Is there any easy way to do this?</p>
  
  <p><strong>EDIT</strong>
  To be more specific the allowed numbers and letters in serial number need to be 0-9 and A-Z. To make it more generic I need to have 2 short strings for example encoded in that serial number. For example a date "04/03/2013" and one number "324" or email address if possible. The string don't need to be human readable in the serial number but I need to be able to retrieve them when needed.</p>