Efficient group signatures with verifier-local revocation employing a natural expiration

This paper presents a novel proposal of group signatures with verifier-local revocation employing a natural expiration to ensure an efficient verification of signatures and a revocation check. Current group signatures have an expensive verification phase which takes several pairing operations and checks a long-sized revocation list, especially, if a large number of users are in the group. Generally, the revocation list grows linearly every time when a new revoked user is added into the list unless group parameters and keys are not reinitialized. Nevertheless, the reinitialization is not feasible and burdens the communication overhead in many communication systems. In these schemes, the verification of several signatures with the long-sized revocation list takes too much time. Our proposed group signature scheme offers the more efficient verification phase which employs the revocation list that is reduced in time by a natural expiration of group member secret keys. Due to an optimization in the verification phase, our scheme is more efficient than related solutions.