What is the difference between Authentication and Authorization in SharePoint?

Ans

Authentication is the process by which the identity of a user who requests access to a SharePoint web application is verified.  

Authorization, which is the process by which a user is granted access to specific resources within a SharePoint site.  

Simply put, Authentication controls whether or not a user has permission to access sites on a SharePoint web application.  Authorization controls what documents, lists, libraries, etc. a user can access on a SharePoint site once they have been successfully authenticated.

SharePoint 2013 supports the following authentication types:

• Windows authentication
• Forms-based authentication
• SAML token-based authentication