title: Generating a product key
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/1015573/secure-algorithm-for-creating-license-keys">Secure algorithm for creating license keys?</a>  </p>
  </blockquote>
  
  
  
  <p>Im looking for a way to create 25 character keys based on a specific pattern, so that i can check if it is valid without any sort of internet connection, etc.</p>
  
  <p>Ive been trying several possible ways to do this, but with no success.</p>