title: How to prevent time-based cheats on a time-based simulation game?
body: <p>In the iphone game "Tiny Tower", I'm guessing it uses some kind of simulation based on the time spent between the last play and the current time, because you can set the current time forward and you will get the benefit from the fake elapsed time span.</p>
  
  <p>Is there an algorithm that I can use to prevent this sort of thing?  (Or at least make it difficult enough for the average user to pull off!)</p>
  
  <p>Edit:  thanks, I understand that, despite my wording, there's no way to prevent things you store on the client side, but I want to make it at least more difficult than "changing the time" to hack it!</p>