Or-protocols for Anonymous Membership Proofs in Ad-hoc Networks

Ad-hoc networks formed by peers without relying on any preexisting infrastructure, have been a very attractive field of academic and industrial research in recent years due to their potential applications. An ad-hoc network allows a peer node further to form a task-driven sub-network such that each node in the generated sub-network may exchange data with each other but any other non-member node is prohibited to access the subnetwork. As a result, a task-driven subnetwork generated by a peer node definitely requires membership proof mechanism (in the scenario of anonymous communications, anonymous membership proof systems are required). In this paper, we provide a novel mechanism for anonymous access control (anonymous membership proof systems) in ad- hoc networks based on a new notion which we call or-protocols in the common reference string model. An or-protocol in essence is a three move zero-knowledge proof system that allows a peer node to prove its membership of a given set which is publicly verifiable. Our protocol is of constant size, i.e., the length of a proof is independent with number of users in a given set, and thus is suitable for practice. Furthermore we show that our protocol is provably secure assuming that the discrete logarithm problem defined over prime field is hard.