title: Difference between Authorize and Request.IsAuthenticated
body: <p>I am relatively new to ASP.NET MVC and I am encountering the following piece of code very often:</p>
  
  <pre><code>[Authorize]
  public ActionResult Index()
  {
    if (Request.IsAuthenticated)
    // ...
  }
  </code></pre>
  
  <p>Is the if-statement really necessary? Can somebody please explain the differences between the two?</p>