Authentication vs. Authorization

Authentication: This is the process of verifying a user's identity. For instance, when Alice logs in with her username and password, the server uses the password to authenticate her.

Authorization: This process determines if an authenticated user is permitted to perform a specific action. For example, Alice may have permission to retrieve a resource but not create one.

Microsoft provides some essential tools like claims, roles, and policies to implement authorization, but a significant part of the work must be customized to your specific needs for your application.

For more detailed information and practical examples, you can visit Microsoft's official documentation on ASP.NET Core Security. see here