How do authentication and authorization work, specifically using OAuth2?

Question

Accepted Answer

OAuth2 is a protocol for authentication and authorization that allows third-party applications to access user data without sharing passwords.

OAuth2 provides a secure and standardized way for users to grant access to their resources to third-party applications.
It involves the exchange of tokens between the user, the third-party application, and the resource server.
Authentication is handled by the authorization server, which verifies the user's identity and issues an access token.
Authorization is handled by the resource server, which checks the access token to determine if the user has permission to access the requested resource.
OAuth2 supports several grant types, including authorization code, implicit, client credentials, and resource owner password credentials.
Examples of OAuth2 providers include Google, Facebook, and Twitter.

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