A scalable Privacy-preserving authentication framework for the public ubiquitous computing environments = 공공유비쿼터스컴퓨팅환경을위한효율적이며 확장성이개선된인증프레임워크연구

After the concept of ubiquitous computing environment was introduce by M. Weiser in 1991, many researcher proposed their idea to address challenge issues of ubiquitous computing environments. Recently, marvelous advance of fundamental technologies for ubiquitous computing environments (i.e., sensor network and 4G network) enable us to expect the ubiquitous computing environments will be come true in near future. Based on these research outputs and the advance of fundamental technologies, some of the ubiquitous computing environments (e.g., Navitime in Japan, open urban testbed in Finland, and child-care & safety service in Korea) have been integrated in our real life. From now, we call the ubiquitous computing environments integrated in the real life as the public ubiquitous computing environments. Compared to the ordinary ubiquitous computing environment, the public ubiquitous computing environments have the following properties: multiple administrative domains, complicated trust model, numerous subscribers of a service, heterogeneous devices, and numerous authentication requests. Although these properties causes the security and privacy problems, the previous work cannot solve these problems: the leakage of the stored subscription information to enforce proper access control, privacy violation due to traceability of the end-user, and low scalability due to the heavy computational overhead and communication cost. To address these problems, we propose a scalable privacy-preserving authentication framework, consisting of three privacy-preserving authentication protocols: anonymous authentication protocol, privacy-preserving membership verification protocol, and anonymous re-authentication protocol. All protocols reduce the processing delay time and communication overhead while preserving the privacy of the end-user. The privacy-preserving membership verification protocol allows the service provider to adjust its performance to satisfy his/her desire performance in the various services. In addition, the processing delay time does not be affected by the number of the service subscriber. Also, the protocol can preserve the privacy of the end-user based on computationally hard problem. Through a set of the selected numbers and standard version of membership verification, the anonymous authentication protocol enhances non-linkability and removes the privacy concern regarding to the abuse of the stored service subscription information in the anonymous authentication protocol. The anonymous re-authentication protocol employing the lightweight version is used to provide an efficient anonymous re-authentication. If the end-user has authenticated in the previous session, the end-user can share a secret information with the wireless sensor network. The proposed anonymous re-authentication verifies whether the end-user has the secret information or not. In order to illustrate how to employ these authentication protocols to build privacy-preserving protocols for the public ubiquitous computing environments, we provide a privacy-preserving secure service discovery protocol as one example. In addition, we demonstrate that the proposed protocols address the security and privacy problems of the possible services, child-care and safety service, in the public ubiquitous computing environments.