Which authentication mechanism enables one login for multiple applications using standards like SAML or OIDC?

• A. Multi-factor authentication
• B. Single Sign-On
• C. Passwordless Login
• D. Biometric only login

Answer: (B)

Single Sign-On lets you authenticate once with a trusted identity provider and then access many applications without re-entering credentials. Standards like SAML and OpenID Connect are designed for this flow. SAML uses XML-based assertions from the identity provider to each service, typically via browser redirects, so the service trusts your authenticated state. OpenID Connect, built on OAuth 2.0, provides an ID token that verifies who you are to each application. Once you’re logged in, a session with the identity provider is relied on by multiple apps, reducing repeated logins and credential management for the user.

This approach improves user experience and can tighten security by centralizing how identities are verified, but it also means the identity provider becomes a critical security focus. Other options describe methods that can complement SSO (like MFA) or different login styles, but they don’t themselves enable one login used across multiple applications with SAML or OIDC.