Federated identity

A way to enable users to access multiple applications or systems using a single set of credentials or identity, which are managed by a third-party identity provider.

In other words, it's a mechanism that allows different organizations or systems to trust each other and share user identity information securely.

With federated identity, users only need to authenticate once with the identity provider and can then access all the applications or services that are part of the federation, without having to log in again for each one. This can simplify the user experience and reduce the burden on users to remember multiple passwords and manage multiple accounts.

Federated identity is often used in enterprise environments where different systems or applications are used by different departments or organizations, but it can also be used for consumer-facing services such as social media platforms or online marketplaces. Examples of federated identity protocols include SAML (Security Assertion Markup Language), OAuth (Open Authorization), and OIDC (OpenID Connect).