Hierarchical Mobile Certificate Authority for Heterogeneous Wireless Ad Hoc Networks: Architecture and Protocols

Wireless Mobile Ad Hoc Networks (MANETs) provide an extremely flexible method for establishing communications in situations where geographical or terrestrial constraints demand a totally distributed network system without any fixed infrastructure. However, MANETs are particularly vulnerable to various attacks due to their fundamental characteristics, such as open medium, dynamic topology, distributed cooperation, and constrained capability in power, computation and storage. In this paper, we focus on the key management scheme - one of the core schemes for deploying security services in wireless ad hoc networks. We propose a hierarchical mobile certificate authority (HMCA) scheme for large scale wireless ad-hoc networks by exploring the heterogeneous security and physical characteristics of mobile nodes. In particular, we develop the architecture and relevant protocols for HMCA to provide major certification services such as certificate issuing, renewal, retrieval, and revocation. We also consider the situations where any client node, certificate issuing node, or regional leader node dies or moves to another region within the network.