title: How to license my c# application
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/3624149/license-for-c-sharp-desktop-application">License for C# desktop application</a>  </p>
  </blockquote>
  
  
  
  <p>I want to make my program lock after some days of trial use and if a user purchase a license, can use the program for some months.</p>
  
  <p>I dont know a way to do this. An idea is to make a local temp key when the program is installed, and lock it after the days passed(the problem here is that user can change date and time of his computer.. the philosophy of the program is to be used online and offline, so i cant compare dates from my server to the computer).</p>
  
  <p>And the other thing is, how to make a license service. I can generate lots of serial keys and then when a user pays i can give him a serial, and every time the program starts i can check if the serial is in my web service.</p>
  
  <p>Am i in a good road?? Any suggestions?</p>