The document provides an overview of OAuth 2.0 and OpenID Connect (OIDC) protocols. It discusses how OAuth limits information sharing between parties in a protocol to improve security. It presents a diagram showing the separation of username, codes, tokens, sessions, and other credentials between the user agent, authorization server, client, and protected resource in the OAuth authorization code flow. The document emphasizes that OAuth and OIDC aim to avoid password proliferation, enable authentication and authorization across different systems, and provide a standardized user identity API.