OpenID Connect
OpenID Connect
OpenID Connect is an authentication protocol built on top of OAuth 2.0 that allows clients to verify the identity of end-users based on the authentication performed by an authorization server. It provides a standardized way for clients to request and receive identity information about users from identity providers (IdPs), enabling single sign-on (SSO) authentication across different applications and services.
Overview
OpenID Connect was developed in 2014 as an extension to OAuth 2.0, providing an identity layer on top of the authorization framework. It introduces additional endpoints and data formats for authentication and identity information exchange, making it easier for clients to verify user identities and obtain user profile information.
How It Works
- Client Application: The application that requests authentication and identity information about the user.
- Identity Provider (IdP): The server that authenticates users and provides identity information to clients.
- Authorization Server: The server that handles authentication and authorization requests and issues access tokens and ID tokens to clients.
- User: The individual whose identity is being verified by the client application.
Key Features
- Single Sign-On (SSO): OpenID Connect enables users to authenticate once and access multiple applications and services without re-entering their credentials.
- ID Tokens: OpenID Connect introduces ID tokens, which contain identity information about the user, including their unique identifier (sub), name, email address, and other profile attributes.
- Standardized Endpoints: OpenID Connect defines standardized endpoints, such as the authorization endpoint, token endpoint, and userinfo endpoint, for authentication and identity information exchange.
- Discovery Mechanism: OpenID Connect provides a discovery mechanism that allows clients to dynamically discover the endpoints and configuration details of the authorization server.
Flows
OpenID Connect supports several authentication flows, including:
- Authorization Code Flow: Used by web applications to obtain ID tokens after user authentication and authorization.
- Implicit Flow: Used by client-side applications, such as single-page applications (SPAs), to obtain ID tokens directly from the authorization endpoint.
- Hybrid Flow: Combines aspects of the authorization code flow and the implicit flow, providing both ID tokens and access tokens to the client application.
Applications
OpenID Connect is commonly used for various authentication purposes, including:
- Single Sign-On (SSO): Providing seamless authentication across multiple applications and services without requiring users to re-enter their credentials.
- User Authentication: Authenticating users to web and mobile applications, allowing them to access personalized content and services.
- API Access: Enabling third-party developers to access user data and perform actions on behalf of users through APIs provided by platforms and services.
Conclusion
OpenID Connect is a powerful and widely adopted authentication protocol that provides a standardized way for clients to verify user identities and obtain identity information from identity providers. By leveraging OAuth 2.0 and introducing ID tokens and standardized endpoints, OpenID Connect simplifies the process of authentication and identity management, enabling secure and seamless user authentication across different applications and services.
