Single Sign-On (SSO)

One Identity, Everywhere

Single Sign-On (SSO) is the cornerstone of modern identity architecture. It eliminates the friction of multiple credentials by allowing an identity established in one session to be trusted across an entire ecosystem of independent applications. SSO is not merely a convenience; it is a critical security control that centralizes authentication policy and drastically reduces the attack surface of an organization.

SSO

Seamless Access

Core Mission

Elimination of Credential Fragmentation. Providing a unified authentication event that simplifies the user journey while centralizing security enforcement.

Like a Universal Keycard: You check in once at the front desk (the Identity Provider). You receive a single card that opens your room, the gym, the executive lounge, and the parking garage—without you having to register at every door.

Corporate Portals / SaaS Ecosystems / Customer Identity

The SSO Landscape

Choosing an SSO pattern depends on your application stack, security requirements, and the relationship between your identity source and your service providers.

Strategic SSO Comparison

Pattern	Primary Protocol	Best For	Technical Complexity
Enterprise SSO	SAML 2.0	Legacy apps, Corporate IT, B2B.	Medium (XML/Certs)
Web/Cloud SSO	OIDC	Modern Web, Mobile, SPAs.	Low (JSON/JWT)
Shared Cookie	Proprietary	Internal subdomains (same parent domain).	Variable
Desktop SSO	Kerberos / IWA	Windows AD / Intranet environments.	High (Network Setup)

The Federated SSO Dance

Regardless of the protocol, modern SSO follows a consistent architectural pattern of redirection and cryptographic proof.

1

Initiate

The user attempts to access a Service Provider (SP). If no session exists, the SP redirects the user's browser to the Identity Provider (IdP).

2

Authenticate

The user authenticates with the IdP (e.g., via MFA or Biometrics). The IdP validates the identity and generates a signed proof (Assertion or ID Token).

3

Deliver

The IdP redirects the user back to the SP with the signed artifact. The SP verifies the signature and establishes a local session—seamlessly logging the user in.

---

Detailed SSO Implementation Guides

Master the nuances of different SSO patterns across your infrastructure.

SAML 2.0

The industry standard for enterprise SSO and B2B federation.

OpenID Connect

Modern, REST-friendly SSO built on the OAuth 2.0 framework.

Session Management

Handling timeouts, sliding windows, and global logout (SLO).

IdP Discovery

Implementing Home Realm Discovery to route users to the correct login page.

Adaptive SSO

Context-aware login that triggers additional factors only when risk is detected.

Next Steps

• Review Security Best Practices to prevent common SSO vulnerabilities like replay attacks.
• Explore Zero Trust Architecture for re-verifying SSO sessions.
• Check Governance Patterns for auditing SSO access.