What's the difference between OpenID and OAuth?

Question

I\'m really trying to understand the difference between OpenID and OAuth? Maybe they\'re two totally separate things?

Answer 1

OpenId uses OAuth to deal with authentication.

By analogy, it's like .NET relies on Windows API. You could directly call Windows API but it's so wide, complex and method arguments so vast, you could easily make mistakes/bugs/security issue.

Same with OpenId/OAuth. OpenId relies on OAuth to manage Authentication but defining a specific Token (Id_token), digital signature and particular flows.