Introduction to Single Sign-On (SSO)

Introduction:

• Single Sign-On (SSO) is a mechanism that allows users to authenticate once and gain access to multiple applications or systems without the need to re-enter their credentials. It provides a seamless and convenient user experience while improving security and reducing administrative overhead.

• SSO can be implemented using various protocols and technologies:
  1. SAML (Security Assertion Markup Language)
  2. OAuth
  3. OpenID Connect
• These protocols enable the exchange of authentication and authorization information between the identity provider (IdP) and the service provider (SP).

• The IdP is responsible for authenticating the user, while the SP relies on the IdP’s assertion to grant access.

• To implement SSO, organizations typically need to configure an identity provider, integrate it with their applications or systems, and establish trust relationships between the IdP and SPs.
• This involves setting up federation metadata, configuring trust certificates, and defining attribute mappings.

Working of an SSO application:

• Single Sign-On (SSO) works by establishing a trust relationship between an identity provider (IdP) and multiple service providers (SPs).
• Here’s a simplified step-by-step process:

1. User Authentication:
   • The user logs into the IdP with their credentials. This is the only time the user needs to enter their credentials during the entire session.
2. Service Request:
   • The user attempts to access a service or application (SP). The SP needs to verify the user’s identity, so it sends a request back to the user’s system.
3. Identity Verification:
   • The user’s system generates an SSO assertion, often in the form of a security token that contains the user’s credentials and sends it to the SP. This assertion is created and signed by the IdP.
4. Assertion Validation:
   • The SP receives the SSO assertion, validates it by checking the IdP’s signature, and extracts the user’s credentials.
5. Access Granted:
   • If the validation is successful, the SP grants access to the user. The user does not need to log in to the SP directly.

• Further Requests: For any further requests to the same or different SPs during the session, steps 2-5 are repeated.
• However, the user doesn’t need to provide their credentials again, as they are stored in the SSO assertion.

Benefits:

• Simplifies the login process for users, improving productivity.
• Reduces the risk of lost or forgotten passwords.
• Improves user experience by eliminating the need for multiple passwords.
• Enhances security by enabling centralized control over user authentication.