  This paper describes a solution for the efficient management of revocation in
vehicular ad-hoc networks, for both certificate-based and identity-based
authentication. It proposes the use of an authenticated data structure based on
a dynamic hash tree, which is a perfect $k$-ary tree, together with a new
version of the SHA-3 hash function. This combination allows optimizing search
and insertion operations in the tree. Consequently, the proposal is very useful
both when vehicular networks are widely used, and in urban environments.
Simulation results are promising and confirm this hypothesis.
