title: How to mask number to look as it would be random value
body: <p>Database resources, that can be accessed from webpage that I'm currently working on, have unique id number with auto_increment set. So url would have to look like some.web.page.com/resource/<em>id-number</em>.</p>
  
  <p>It would be kinda easy for user to notice that he can simply increase or decrease number at the end to get anything he pleases and while security isn't big concern in this case, I would really like to prevent that kind of behavior.</p>
  
  <p>I was trying to find some function that would convert the number to random string look-a-like, but I failed (didn't really know what to put in that field on google.com ;) ). I also have my own ideas, but I prefer to use method that is already working well somewhere. The function needs to be symmetrical so I can easily generate string, and get number from that string. Any advice?</p>