Group Authentication

A new type of authentication, call group authentication, which authenticates all users belonging to the same group is proposed in this paper. The group authentication is specially designed for group-oriented applications. The group authentication is no longer a one-to-one type of authentication as most conventional user authentication schemes which have one prover and one verifier; but, it is a many-to-many type of authentication which has multiple provers and multiple verifiers. We propose a basic t-secure m-user n-group authentication scheme ((t, m, n) GAS), where t is the threshold of the proposed scheme, m is the number of users participated in the group authentication, and n is the number of members of the group, which is based on Shamir´s (t, n) secret sharing (SS) scheme. The basic scheme can only work properly in synchronous communications. We also propose asynchronous (t, m, n) GASs, one is a GAS with one-time authentication and the other is a GAS with multiple authentications. The (t, m, n) GAS is very efficient since it is sufficient to authenticate all users at once if all users are group members; however, if there are nonmembers, it can be used as a preprocess before applying conventional user authentication to identify nonmembers.