Limited-lifetime shared-access in mobile systems

We propose a simple access protocol to shared information in a mobile environment. The objective of the proposed scheme is to allow a specified set of users access to shared information and protect the confidentiality of the information from users outside this set. The set of users may be updated from time to time. In particular, the duration during which a user is allowed access to the shared information may be restricted. Furthermore, the information itself has limited lifetime and the confidentiality of the information has to be preserved during this lifetime only. The proposed access protocol is in particular suited to the mobile environment, because of the loose binding of the communicating entities