Identifier Migration for Identity Continuance in Single Sign-On

Single sign-on (SSO) is an identity management technique that provides the ability to use multiple Web services with one set of credentials. However, when the authentication server is down or unavailable, users cannot access these Web services, regardless of whether they are operating normally. Therefore, it is important to enable continuous use alongside SSO. In this paper, we present an identity continuance method for SSO. First, we explain four such continuance methods and identify their limitations and problems. Second, we propose a new solution based on an identifier migration approach that meets the requirement for identity continuance. Finally, we discuss these methods from the viewpoint of continuity, security, efficiency, and feasibility.