What is Single Sign-On (SSO)?

Single Sign-On, or SSO, is a method of authenticating users to grant them access to multiple independent software applications and services via a single set of login credentials. Instead of remembering a unique username and password for every application, a user can log in once and gain access to all connected services during a single session.

How Single Sign-On (SSO) Works

SSO operates on a trust relationship between two main components:

• The Identity Provider (IdP) is the central service that authenticates the user. Examples include Okta, Microsoft Authenticator, Google, or Microsoft Entra ID (formerly Azure AD).
• The Service Provider (SP) is the application or website that the user wants to access.

Single Sign-On centralizes authentication so that users can access multiple applications via a single login. The SSO authentication process typically follows these steps:

• Initial Login: A user attempts to access a service provider (i.e., a company's internal application).
• The Redirect: The service provider redirects the user's browser to the identity provider to be authenticated.
• Authentication: The user enters their single set of credentials (username and password) on the identity provider's login page.
• Token Generation: Once authenticated, the identity provider creates a secure, digitally signed authentication token that gets passed back to the service provider.
• Granting Access: The service provider validates this token and grants the user access to the application. 

For the remainder of the session the user is automatically granted access because the identity provider has already verified their identity.

Benefits of Single Sign-On (SSO)

SSO provides significant benefits for both organizations and individual users.  

How Users Benefit from Single Sign-On (SSO)

• Convenience: SSO eliminates "password fatigue," which is the frustration of having to remember and manage dozens of different passwords.
• Increased Productivity: With frictionless password management, users spend less time logging in and resetting forgotten passwords, so they can be more productive.

How Organizations Benefit from Single Sign-On (SSO)

• Enhanced Security: With centralized authentication, Single Sign-On encourages users to create and use one strong, complex password instead of multiple weak ones. It also simplifies the process of deprovisioning users, since an administrator only needs to disable one account to revoke access to all connected services.
• Reduced IT Costs: Fewer password resets mean a reduction in calls to the IT help desk, freeing up IT staff to focus on more strategic tasks.
• Simplified Compliance: Centralized access management and audit trails make it easier to demonstrate compliance with regulations that require strict access controls.

Frequently Asked Questions About Single Sign-On (SSO)

Is Single Sign-On (SSO) more secure than traditional logins? 

Yes, SSO can significantly enhance security. It encourages users to create and use one strong password, reducing the risk of using multiple weak or reused passwords. Additionally, it simplifies user deprovisioning. When an employee leaves the company, an administrator only needs to disable one account to revoke access to all connected services, which is much faster and more secure than disabling each account individually.

What is the difference between SSO and Multi-Factor Authentication (MFA)? 

SSO is about convenience and centralized access—using one set of credentials to access multiple applications. MFA is about enhanced security—requiring two or more verification factors (like a password and a code from a phone app) to prove a user's identity. These two technologies are complementary and are often used together to provide both convenience and a higher level of security.

What is an Identity Provider (IdP)? 

An Identity Provider (IdP) is the service that stores and verifies user identities. It's the "trusted" third party in the SSO process. When a user tries to log in to an application, they are redirected to the IdP's login page to enter their credentials. Once the IdP confirms the user's identity, it sends a secure token back to the application to grant access.

Can SSO work with all applications? 

No, for SSO to work, both the Identity Provider and the application (the Service Provider) must support one of the common SSO protocols, such as SAML (Security Assertion Markup Language) or OAuth. Most modern business applications and cloud services are built with SSO compatibility, but some older or niche applications may not support it.

How does SSO save a company money? 

SSO helps organizations reduce IT costs by minimizing the number of password-related help desk tickets. With fewer password resets and lockouts, IT staff can spend less time on routine support tasks and more time on strategic projects. It also streamlines the onboarding and offboarding processes for employees, saving time and resources.