In the modern enterprise, employees use dozens of SaaS applications every day from Google Workspace and Slack to Salesforce and Jira. Managing credentials for every app separately isn’t just inconvenient, it’s risky.

That’s where Single Sign-On (SSO) comes in.

SSO enables users to log in once and gain access to all authorized applications securely. It’s a cornerstone of identity and access management reducing friction for users and strengthening enterprise security.

But behind this simplicity lies a powerful set of authentication and authorization protocols that make it all work seamlessly: SAML, OAuth 2.0, and OpenID Connect (OIDC).

What is Single Sign-On (SSO)?

Single Sign-On (SSO) is a centralized authentication process that allows a user to access multiple applications using a single set of credentials.

For example, when an employee logs into their company’s identity provider (IdP) like Okta or Azure AD, they can automatically access tools like Salesforce, Slack, and Zoom without logging in again.

This not only improves user experience but also enhances:
✅ Security (fewer passwords to manage)
✅ Compliance (centralized access control)
✅ Efficiency (faster login and reduced IT support tickets)

The Three Major SSO Protocols Explained

There are three main protocols that power modern SSO systems. Each plays a unique role depending on the type of applications being accessed.

1. SAML 2.0 (Security Assertion Markup Language)

Best for: Enterprise SaaS applications (like Salesforce, Box, or Workday)

SAML is an XML-based protocol that allows an Identity Provider (IdP) to authenticate users and pass that information to a Service Provider (SP).

• Authentication flow: The IdP verifies the user and sends a digitally signed XML token (called an assertion) to the SP.
• Format: XML
• Strength: Mature and widely supported for enterprise SSO integrations
• Weakness: Complex setup and limited support for mobile apps or APIs

✅ Example: You log into Okta, which authenticates you and sends a SAML assertion to Salesforce, granting access.

2. OAuth 2.0 (Open Authorization)

Best for: Authorizing API access between applications

OAuth 2.0 isn’t an authentication protocol it’s an authorization framework.
It allows an app to access data from another app without exposing user credentials.

• Authentication flow: The user grants permission to an app to access limited resources on their behalf (via access tokens).
• Format: JSON
• Strength: Ideal for API-driven integrations
• Weakness: Needs OIDC or another layer for authentication

✅ Example: When you use “Sign in with Google” to connect a third-party app, OAuth 2.0 handles token-based access.

3. OpenID Connect (OIDC)

Best for: Web and mobile applications needing authentication + authorization

OIDC builds on top of OAuth 2.0 by adding a standardized way to verify a user’s identity.
It introduces the ID Token, a JSON Web Token (JWT) that contains verified user identity information.

• Authentication flow: The user authenticates with an IdP and receives an ID token + access token.
• Format: JSON (JWT)
• Strength: Modern, lightweight, mobile-friendly
• Weakness: Still evolving and less supported by legacy enterprise apps

✅ Example: Logging into Slack using your company’s Microsoft 365 credentials via OIDC.

How SSO Protocols Strengthen Security

Each of these protocols enhances enterprise security in its own way by:

• Reducing password fatigue and password reuse risks
• Enforcing centralized access policies and MFA
• Supporting automatic user deprovisioning when accounts are disabled
• Enabling seamless auditing and compliance reporting

However, while these protocols secure access, they don’t tell you which applications exist in your environment or who owns them that’s where Application Governance becomes critical.

IAM and Beyond: Where AppGovern Adds Value

SSO protocols are essential for securing user access, but they don’t provide visibility into the entire SaaS ecosystem.

Even with strong IAM and SSO configurations, organizations often face:

• Shadow IT apps connected via OAuth without IT oversight
• Multiple instances of the same SaaS tool managed by different teams
• Unclear ownership of who manages access or renewals
• Unused or dormant licenses wasting budget

AppGovern bridges this gap through Enterprise Application Governance (EAG) providing visibility into every connected app, its access patterns, ownership, and usage metrics.

So while IAM ensures secure authentication via SSO, AppGovern ensures accountability, visibility, and optimization across all your applications.

The Future of Secure and Smart Access

As organizations evolve toward Zero Trust and AI-powered identity systems, SSO remains a vital piece of the puzzle but not the full picture.

Modern enterprises need a layer of governance on top of IAM and SSO one that brings together:

• Identity insights
• Application visibility
• Compliance automation
• Cost optimization

That’s what AppGovern’s Enterprise Application Governance delivers a unified view where security meets intelligence.

Final Thought

SSO protocols like SAML, OAuth 2.0, and OIDC make seamless authentication possible but visibility into app sprawl, ownership, and governance keeps your ecosystem secure and sustainable.

Together, they create a foundation for modern digital trust.