Securing multicast communications in Mobile Ad Hoc Networks (MANETs) is now considered among the most challenging research directions in the areas of wireless networking and security. MANETs are emerging as the desired environment for an increasing number of commercial and military applications, addressing also a growing number of users. Security on the other hand, is now an indispensable requirement for these applications. However, the limitations of the dynamic, infrastructure-less nature of MANETs impose major difficulties in establishing a secure framework suitable for group communications.

The design of efficient key management (KM) schemes for MANET is of paramount importance, since the performance of the KM functions (e.g. group key generation, entity authentication) imposes an upper limit on the efficiency and scalability of the whole secure group communication system. In this work, we contribute towards efficient, robust and scalable secure group communications for MANETs by extending the TGDH scheme to a novel distributed and topology aware protocol: DS-TGDH.

Our aim is to modify TGDH so that: a) it is feasible in the most general resource-constrained flat MANET where no nodes with special capabilities may exist, b) it produces considerably lower overhead for the network nodes involved, c) it handles disruptions with low cost. To meet our objectives we consider in our design the underlying routing protocol, and we apply a distributed version of TGDH over a robust schedule, optimizing parameters of interest. We assume that members have already been authenticated and we focus on the design and analysis of the einforcedDS-TGDH. We compare our scheme with the original, w.r.t. this cross-layer consideration.

Through our analysis and results we shed more insight on the actual feasibility of these protocols for MANETs and provide more realistic and aircomparison results that more accurately advocate the pros and cons of each protocol over the environment of interest.