ISC Identity Management · Updated November 2026
SSO vs Federated Identity: Is One Login the Same as Cross-Organization Trust?
SSO reduces repeated logins. Federation extends trust between separate identity domains.
Single sign-on
SSO lets a user authenticate once and access multiple connected applications without reentering credentials for each one.
Federated identity
Federation allows separate organizations or security domains to trust identity information provided by another identity provider.
Identity provider
The identity provider authenticates the user and can issue assertions or tokens consumed by service providers.
They can overlap
A federated environment often creates an SSO experience, but SSO can also exist entirely inside one organization.
The takeaway
SSO is about using one authentication session across multiple applications. Federation is about one domain trusting identity assertions from another.
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FAQ
Is SSO always cross-company?
No.
Can federation support SSO?
Yes.
Does SSO eliminate the need for strong authentication?
No.