Design of a scalable single sign-on for web service

Web service is a kind of SOA (Service Oriented Architecture) and single sign-on is one of the key technologies in web service. Single sign-on enables a use to log in only once and get all the services it wants in a distributed system. This paper proposes a scalable single sign-on scheme, which can support identity federation and work in a standard way. The web service system is divided into multiple security domains where the SAML assertion is used as security token in the system for authentication and authorization. Identity federation based on SAML assertion and Web Service Security Trust enables web service clients both inside and outside their security domains to access the services in a simple and secure way.