What is Single Sign-On (SSO)?
D1 · General · CompTIA Security+ SY0-701SSO (Single Sign-On) is an authentication scheme that allows users to log in once with a single set of credentials and gain access to multiple independent applications and systems without re-authenticating for each one.
How it works: User authenticates to an Identity Provider (IdP) → IdP issues an authentication token → user presents token to Service Providers (SPs) → access granted without additional login.
Protocols: SAML (enterprise/web SSO), OAuth/OIDC (modern APIs), Kerberos (Active Directory SSO).
How it works: User authenticates to an Identity Provider (IdP) → IdP issues an authentication token → user presents token to Service Providers (SPs) → access granted without additional login.
Protocols: SAML (enterprise/web SSO), OAuth/OIDC (modern APIs), Kerberos (Active Directory SSO).
SSO improves user experience and security (fewer passwords = less password reuse). The risk: if SSO credentials are compromised, all connected apps are exposed. Always pair SSO with MFA. Federated identity extends SSO across organizational boundaries (e.g., logging into a partner's portal with your company credentials).