Counting abuses using flexible off-line credentials

Mobile and ad-hoc networks allow businesses to provide a new range of applications and services and at the same time they introduce new constraints that have important effects on the way in which security primitives must be designed. This is challenging because it translates to a demand of richer and more flexible security primitives that often need to satisfy stricter requirements than traditional wired network scenarios. In this paper we focus on one of this primitive, namely security credentials. We present a solution that extends the existing protocols used to implement off-line credentials such that, not only abuses can be detected but they can also be counted. Our solution addresses the problem of 1-time and 2-times credentials and we will conclude by discussing the challenges that need to be solved to generalize the primitive to k = n.