OpenID Connect (OIDC) Implementation

1. Introduction

OpenID Connect (OIDC) is an authentication layer on top of the OAuth 2.0 protocol, allowing clients to verify the identity of end-users based on the authentication performed by an authorization server.

2. What is OpenID Connect?

OpenID Connect enables clients to obtain basic profile information about the end-user in an interoperable and REST-like manner. It allows for Single Sign-On (SSO) and provides a standardized way to handle authentication.

Key Concepts:

• Identity Provider (IdP): The server that authenticates users and provides identity information.
• Client: The application that wants to authenticate users.
• Authorization Server: The server that issues access tokens and ID tokens.
• ID Token: A JWT (JSON Web Token) containing user identity information.

3. How OIDC Works

OIDC allows clients to authenticate users through a series of steps:

graph TD;
    A[User Agent] -->|1| B[Client App]
    B -->|2| C[Authorization Endpoint]
    C -->|3| D[User Authentication]
    D -->|4| C
    C -->|5| E[Authorization Code]
    E -->|6| F[Token Endpoint]
    F -->|7| G[Access Token & ID Token]
    G -->|8| B
    B -->|9| H[User Info Endpoint]
    H -->|10| B
            

The flow includes user interactions, token issuance, and fetching user information.

4. Implementation Steps

1. Register your application with the OIDC provider.
2. Set up the authorization endpoint in your application.
3. Implement the authorization code flow.
4. Request the ID token from the token endpoint.
5. Validate the ID token and fetch user information.

5. Best Practices

• Use HTTPS to secure communication between the client and the server.
• Implement proper token expiration and refresh mechanisms.
• Ensure proper scopes are requested to limit access to user information.
• Regularly review and update your OIDC configurations to comply with security standards.

6. FAQ