Authenticating multiple web applications through single authentication mechanism

Question

How can I authenticate multiple applications with a single authentication mechanism?. These applications are having existing authentication within them, perhaps I need to authenticate these apps into my system which is isolated from others. Please suggest a better approach

Answer 1

When using OpenID Connect, the first application the user logs in to, will redirect the user's browser to the authorization server (AS). Since the user does not have a session between the browser and the AS, it will present the login screen. The user signs in and is redirected to the application (client) with an ID token and access token. The application will then establish a session between the browser and the application (typically a cookie)

When the user navigates to the second application, it will also redirect the user to the AS, but now the user already has a valid session between the browser and the AS, so the AS won't show the login screen (it may show the consent screen if the user has not consented to the requested scopes), and will issue an ID token and access token to the second application.

Now the user has a authenticated session with both applications with a single sign on (SSO).