title: What is the meaning of Implicit Authentication?
body: <p>I'm developing a plugin for login in my site. During search for that I see the line below:</p>
  
  <pre><code>Implicit Authentication plugins implement support for authenticating users based on http headers.
  </code></pre>
  
  <p>Would you explain its meaning for me ?</p>
  
  <p>Is login using openID an implicit authentication?</p>
  
  <p>Thank you.</p>