Toward unlinkable ID management for multi-service environments

As pervasive computing environments become popular, ID devices, such as smart cards and RFID tags, introduce multi-service environments, in which a user can receive multiple services by one ID device. However, there exists a problem that service providers can trace a user´s behavior by linking the user´s access history, if only one ID is assigned to the user. In this paper, we propose an unlinkable ID management scheme for multi-service environments. Our scheme provides unlinkability of users´ accesses against third-party service providers, by preparing different user IDs for each service, and by using cryptographic protocol to exchange the ID between a user and a service provider, while linkability is assured between the user and the involved provider.