What Is SSO (Single Sign-On)?
Single Sign-On (SSO) is an authentication scheme that allows a user to log in once with a single set of credentials and gain access to multiple independent applications or systems without re-authenticating for each one. SSO is typically implemented through federation protocols such as SAML, OpenID Connect, or OAuth 2.0, with an identity provider (IdP) issuing a trusted token that relying applications accept in place of a fresh login. Organizations deploy SSO to reduce password fatigue, cut helpdesk password-reset costs, and centralize authentication policy — including multi-factor authentication (MFA) — in one place. SSO is a cornerstone of modern identity and access management (IAM) for human users, but it was designed around interactive human logins and does not natively extend to non-interactive machine-to-machine communication.
Why It Matters
SSO solves password sprawl for humans, but it creates a false sense of coverage. Because SSO centralizes human authentication so effectively, security teams often assume identity is 'handled' — while service accounts, API keys, OAuth tokens, and AI agents authenticate through entirely separate, usually unmonitored paths that SSO was never built to see. These non-human identities (NHIs) don't log in through the SSO portal, don't trigger MFA prompts, and often don't expire on a schedule tied to an HR system. The result is a blind spot: a company can have flawless SSO coverage for its 100 employees while running 2,000+ non-human identities with no equivalent authentication discipline. OWASP's 2025 NHI Top 10 research found that 80% of identity breaches involve a non-human identity — precisely the population SSO doesn't touch. A compromised API key or long-lived OAuth token can grant an attacker the same application access an SSO login would, without ever appearing in SSO logs or triggering an SSO-based alert.
How Cydenti Helps
Cydenti extends identity visibility to the population SSO was never designed to cover. It discovers and inventories service accounts, API keys, OAuth tokens, and AI agent credentials across cloud, SaaS, and on-prem environments, mapping which systems each non-human identity can reach and flagging risky patterns — stale tokens, excessive privileges, and toxic combinations — that sit outside any SSO policy. Rather than replacing SSO, Cydenti closes the gap it leaves open, giving security teams one consistent view of both human and non-human authentication risk. For teams whose SSO deployment looks complete but whose machine identity footprint has never been audited, that's where Cydenti starts.
Explore →Frequently Asked Questions
Does SSO protect API keys and service accounts?
No. SSO governs how humans authenticate to applications through an identity provider; it does not apply to API keys, service accounts, or OAuth tokens used for machine-to-machine communication. These non-human identities authenticate through separate mechanisms — often long-lived secrets — that fall outside SSO policy, MFA enforcement, and SSO-based session monitoring entirely.
What's the difference between SSO and IAM?
SSO is one authentication feature within the broader discipline of Identity and Access Management (IAM). IAM encompasses provisioning, authorization, lifecycle management, and governance for every identity type — human and non-human — while SSO specifically addresses how a human user authenticates once to access multiple connected applications.
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