OIDC, which stands for OpenID Connect, is an authentication protocol built on top of the OAuth 2.0 framework. It provides a standardized way for applications to authenticate users and obtain their identity information from an identity provider (IdP).

Here are the key components and concepts of the OIDC protocol:

1. Identity Provider (IdP): The identity provider is responsible for authenticating users and providing identity information to relying parties. It acts as a trusted authority that verifies the user’s identity and issues identity tokens.

2. Relying Party (RP): The relying party is the application or service that wants to authenticate users and obtain their identity information. It relies on the identity provider for user authentication and identity token issuance.

3. OAuth 2.0 Framework: OIDC builds upon the OAuth 2.0 framework, which is primarily used for authorization. OAuth 2.0 enables applications to obtain access tokens to access protected resources on behalf of the user. OIDC extends OAuth 2.0 to provide authentication capabilities.

4. ID Token: The ID token is a JSON Web Token (JWT) issued by the identity provider after successful user authentication. It contains information about the user’s identity, such as their unique identifier (sub), name, email, and other optional claims. The ID token is digitally signed by the identity provider to ensure its integrity and authenticity.

5. Authentication Flows: OIDC supports various authentication flows, including the Authorization Code Flow, Implicit Flow, Hybrid Flow, and Device Flow. These flows define how the authentication process is initiated and how the ID token is obtained by the relying party.

6. Discovery and Metadata: OIDC includes mechanisms for discovery and metadata exchange. The identity provider publishes metadata that describes its capabilities, endpoints, and supported authentication flows. Relying parties can use this metadata to dynamically configure their authentication process.

7. User Consent and Authorization: OIDC allows users to grant consent to the relying party for accessing their identity information. The identity provider presents a consent screen to the user, explaining the requested permissions and allowing them to authorize or deny access.

OIDC provides several benefits, including:

OIDC is widely used in modern web and mobile applications for secure and user-friendly authentication. It provides a standardized and interoperable solution for identity and access management.

– Single Sign-On (SSO): OIDC enables users to authenticate once with the identity provider and then access multiple relying parties without needing to re-enter their credentials.

– Standardized Identity Tokens: OIDC defines a standardized format for identity tokens (ID tokens), making it easier for applications to consume and verify user identity information.

– Enhanced Security: OIDC incorporates security measures, such as token encryption and signature verification, to ensure the integrity and confidentiality of identity tokens.

– User-centric Identity: OIDC puts the user at the center of the authentication process, allowing them to control their identity information and grant consent to the relying parties.