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.