title: How do I implement a iOS 13 SSO extension?
body: <p>In June 2019 Apple presented the <a href="https://blog.cortado.com/ios-13-enterprise-features/" rel="nofollow noreferrer">iOS 13 SSO extension</a>:</p>
  
  <blockquote>
    <p>The new iOS 13 Single Sign-on (SSO) extension acts as the middle man that allows native apps and safari to authenticate with an identity provider.</p>
  </blockquote>
  
  <p>And there are two videos on the Apple website, one about the presentation (<a href="https://developer.apple.com/videos/play/wwdc2019/303/" rel="nofollow noreferrer">here</a>, min 44:44) and one introductory (<a href="https://developer.apple.com/videos/play/tech-talks/301/" rel="nofollow noreferrer">here</a>).</p>
  
  <p>I'm interested in implementing this functionality, but so far I didn't encounter any documentation nor software that actually implements it.</p>
  
  <p>The only documentation I found is the <a href="https://developer.apple.com/documentation/authenticationservices/asauthorizationsinglesignoncredential?language=objc" rel="nofollow noreferrer">ASAuthorizationSingleSignOnCredential class</a>, which doesn't explain how to implement it.</p>
  
  <p>How can I implement a single sign-on system on iOS? What classes must be used and how should I combine them?</p>