title: .NET exceptions I can throw for Not Authorized or Not Authenticated
body: <p>I have parts of code where I want to throw an Exception whenever a user is not authenticated/not authorized.</p>
  
  <p>So instead of writing my own NotAuthenticatedException and NotAuthorizedException, I was wondering if there are not already some C# standards for these.</p>
  
  <p>I can imagine a lot of programs throw similar Exceptions, and it would not be very useful if everyone 'writes their own wheel' again.</p>