title: Making of Referral System
body: <p>I'm currently working on my Referral System, but I have a problem with protecting it of frauds.
  Okay, here's how it works for now:</p>
  
  <ul>
  <li>user registers and activate it's account</li>
  <li>user now have access to the control panel and there is it's uniqe link in following format: domain.tld/ref/12345</li>
  <li>when someone other click to user's link, he or she must to click a specific button to confirm that is not some kind of fraud (like "click here, you'll get $100" or something)</li>
  <li>system writes visitor's IP in a database and some data to cookies to prevent re-pressing the button. User now have +1 point.</li>
  </ul>
  
  <p>But, the problem is that visitor can change it's IP, clear cookies and hit button again. It takes a few seconds, and that's not OK, that's cheating.</p>
  
  <p>How to prevent it? Is there some trick to get some unique computer ID or something can't be changed that easy?</p>