title: How to implement a simple licensing scheme?
body: <p>No offence intended, but let's not discuss that licensing schemes can be cracked (I know that) and that recourse to the law is usually a better deterrent (maybe in your country, but no in all).</p>
  
  <p>Not my choice - I have been told to implement licensing, just good enough to keep casual hackers away. </p>
  
  <p>What might make this slightly different is that the PCs which will run the software won't always have internet access privileges. </p>
  
  <p>When someone buys the product, I can build licensing info into it &amp; deliver an install CD. But, what happens if they want to buy more licenses? I don't want to have to go on site to update the licensing data, but they may not be able to access my server, nor I theirs.</p>
  
  <p>I was thinking of having licenses in external (encrypted) files, each containing a number of licenses and an expiration date. If the user buys more licenses, then I can email out an additional file &amp; their security cleared IT guys can burn it to CD or USB stick and then copy it to the applications data directory.</p>
  
  <p>Does that seem ok? Can you think of something better? Can you see problems?  I don't have too much time to implement this.</p>