Security Assertion Markup Language (SAML) is an XML-based standard for exchanging authentication and authorization data between security domains. This is normally between an identity provider like Id.Signicat and a service provider (the customer). SAML is a product of the OASIS Security Services Technical Committee (external link).
SAML assumes that the end-user has enrolled with at least one identity provider. This identity provider is expected to provide local authentication services to the end-user. However, SAML does not specify the implementation of these local services; indeed, SAML does not care how local authentication services are implemented.
SAML has been a de facto standard protocol for identity management, and is now supported by most of the biggest actors in the computer industry. Today Id.Signicat supports SAML v.1.1 and v.2.0. For detailed information about SAML, and access to several white papers, please visit this page (external link) on the OASIS website.