title: Anonymously Log In to an App with iCloud Apple ID
body: <p>According to this <a href="https://developer.apple.com/icloud/index.html">CloudKit overview</a>:</p>
  
  <blockquote>
    <p>CloudKit also enables your users to anonymously sign in to your apps with their iCloud Apple IDs without sharing their personal information.</p>
  </blockquote>
  
  <p>I can't find anything else in their documentation about this capability. I already have an app with my own backend, so I wouldn't need any of the back-end-as-a-service features that CloudKit offers, but I would like to take advantage of logging a user in with their iCloud account, much the same way we currently do with Facebook and Twitter.</p>
  
  <p>Is that possible with CloudKit, or do you also have to leverage their BAAS features in order to take advantage of login?</p>