title: Protecting a high value C# application with only one user
body: <p>I have a single application -- written in C# -- which is used by only one user.  I provide this software for a very high monthly fee (> $10,000).  I'd like to protect this application against use by any other user and I'd like to be able to stop the one user from using the application if they stop paying the license fee.</p>
  
  <p>I know that there is no perfect protection scheme, and I've reviewed the many similar questions on SO, but my question is a little different because I have only one client, I have full access to their hardware, and I don't mind taking even a few hours per installation for a substantial increase in security.</p>