OAuth 2.0 is the next evolution of the OAuth protocol which was originally created in late 2006.
OAuth 2.0 focuses on client developer simplicity while providing specific authorization flows for
web applications, desktop applications, mobile phones, and living room devices.
OAuth 2.0 defines four roles:
-
resource owner
An entity capable of granting access to a protected resource. When the resource owner is a person, it is referred to as an end-user. -
resource server
The server hosting the protected resources, capable of accepting and responding to protected resource requests using access tokens. -
client
An application making protected resource requests on behalf of the resource owner and with its authorization. The term "client" does not imply any particular implementation characteristics (e.g., whether the application executes on a server, a desktop, or other devices). -
authorization server
The server issuing access tokens to the client after successfully authenticating the resource owner and obtaining authorization.