Single Sign-On (SSO)
An authentication model in which a user signs in once to an identity provider and gains federated access to multiple applications without re-authenticating.
Full Definition
Single Sign-On (SSO) centralises identity in a trusted identity provider (Okta, Azure AD / Entra ID, Google Workspace, Ping, Auth0) and federates authentication to downstream applications via SAML 2.0 or OpenID Connect. The user signs in once with their IdP; applications accept the IdP's assertion of identity for the length of a session. SSO is paired with MFA at the IdP so the single sign-on is also a strong one.
For privacy and security, SSO is the leverage point for consistent policy: joiner-mover-leaver automation hits the IdP first, access revocations propagate through every connected app on next session renewal, and the IdP's audit trail is the single-pane view of who logged in where. Enterprise contracts for SaaS tools routinely require SAML / OIDC SSO as a baseline. From a DSR perspective, SSO simplifies the 'who had access to this subject's data' question — the IdP's logs are the authoritative first answer.
Related terms
Authentication
The process of verifying that an entity — a user, a service or a device — is who or what it claims to be before granting access.
Multi-Factor Authentication (MFA)
An authentication model that requires two or more independent factors — something the user knows, has, or is — to confirm identity.
Access Control
The set of policies and technical mechanisms that determine who can access which personal data, for what purpose and under what conditions.
Relevant regulations
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