New User Management Technique in Storage Services for Stronger Privacy

Until now, online services including storage services have revealed their clients’ private information in various ways. Regardless of the reason of exposure, the damage caused by such accident is very serious. To support user-specific services, service providers maintain user-related information and the information can be harmful for the privacy of clients when the information is revealed to an adversary. To get rid of the source of the problem, in this work, we will introduce a new technique which permits service providers to support their clients without maintaining user-related information. The basic idea of our work to support the service provider has a set of parameters which are used for verifying the proof generated by a client as an evidence of his right regarding a service. To embody the idea, we will use a group signature scheme which is widely used as a tool for verifying someone’s membership instead of his specific identity. For the security of our scheme, we give provable security of our scheme under formal security models.