Claim-based identity is an approach to authentication in which the access tokens contain the access key information required for authentication, as well as additional information attributes (claims) about the users. Such tokens are referred to as identity tokens.

Claim-based authentication allows a user to use a single token to sign-in to multiple websites, which is referred to as single sign-on. Since some information attributes (claims) are already a part of the token, the user does not have to enter them again after signing in to the application.