This thesis is divided into two parts. The first part explores the difficulties of
bootstrapping and maintaining a security infrastructure for military Mobile Ad Hoc
NETworks (MANETs). The assumed absence of dedicated infrastructural elements
necessitates, that security services in ad hoc networks may be built from the ground
up. We develop a cluster algorithm, incorporating a trust metric in the cluster head
selection process to securely determine constituting nodes in a distributed Trust
Authority (TA) for MANETs. Following this, we develop non-interactive key distribution
protocols for the distribution of symmetric keys in MANETs. We explore
the computational requirements of our protocols and simulate the key distribution
process.
The second part of this thesis builds upon the security infrastructure of the first
part and examines two distributed protocols for MANETs. Firstly, we present a
novel algorithm for enhancing the efficiency and robustness of distributed protocols
for contacting TA nodes in MANETs. Our algorithm determines a quorum of
trust authority nodes required for a distributed protocol run based upon a set of
quality metrics, and establishes an efficient routing strategy to contact these nodes.
Secondly, we present a probabilistic path authentication scheme based on message
authentication codes (MACs). Our scheme minimises both communication and computation
overhead in authenticating the path over which a stream of packets travels
and facilitates the detection of adversarial nodes on the path