Foundations of group signatures: The case of dynamic groups

Recently, a first step toward establishing foundations for group signatures was taken [5], with a treatment of the case where the group is static. However the bulk of existing practical schemes and applications are for dynamic groups, and these involve important new elements and security issues. This paper treats this case, providing foundations for dynamic group signatures, in the form of a model, strong formal definitions of security, and a construction proven secure under general assumptions. We believe this is an important and useful step because it helps bridge the gap between [5] and the previous practical work, and delivers a basis on which existing practical schemes may in future be evaluated or proven secure