Can you explain how the OAuth 2.0 protocol works and its main components?

OAuth 2.0 is an authorization protocol that allows third-party applications to obtain limited access to a user's resources without transmitting their password.

Main components of OAuth 2.0:

• Resource Owner — the user who owns the protected resources.
• Client — the application that wants to access resources on behalf of the user.
• Authorization Server — responsible for authenticating the user and issuing access tokens.
• Resource Server — stores protected resources and verifies access tokens.

Working principle:

1. The client requests permission from the resource owner.
2. After the user's consent, the client receives an authorization code or token.
3. The client sends the code to the authorization server and receives an access token.
4. The client uses the access token to make requests to the resource server.

Example flow with authorization code:

User -> Client -> Authorization Server (login, consent)
Authorization Server -> Client (authorization code)
Client -> Authorization Server (exchange code for access token)
Client -> Resource Server (access token)
Resource Server -> Client (requested resource)

OAuth 2.0 ensures security and convenience, allowing access rights to be limited and not revealing the user's password.