  The emergence of the Mobile Ad Hoc Networking (MANET) technology advocates
self-organized wireless interconnection of communication devices that would
either extend or operate in concert with the wired networking infrastructure
or, possibly, evolve to autonomous networks. In either case, the proliferation
of MANET-based applications depends on a multitude of factors, with
trustworthiness being one of the primary challenges to be met. Despite the
existence of well-known security mechanisms, additional vulnerabilities and
features pertinent to this new networking paradigm might render such
traditional solutions inapplicable. In particular, the absence of a central
authorization facility in an open and distributed communication environment is
a major challenge, especially due to the need for cooperative network
operation. In particular, in MANET, any node may compromise the routing
protocol functionality by disrupting the route discovery process. In this
paper, we present a route discovery protocol that mitigates the detrimental
effects of such malicious behavior, as to provide correct connectivity
information. Our protocol guarantees that fabricated, compromised, or replayed
route replies would either be rejected or never reach back the querying node.
Furthermore, the protocol responsiveness is safeguarded under different types
of attacks that exploit the routing protocol itself. The sole requirement of
the proposed scheme is the existence of a security association between the node
initiating the query and the sought destination. Specifically, no assumption is
made regarding the intermediate nodes, which may exhibit arbitrary and
malicious behavior. The scheme is robust in the presence of a number of
non-colluding nodes, and provides accurate routing information in a timely
manner.
