  Mobile Ad Hoc networks, due to the unattended nature of the network itself
and the dispersed location of nodes, are subject to several unique security
issues. One of the most vexed security threat is node capture. A few solutions
have already been proposed to address this problem; however, those solutions
are either centralized or focused on theoretical mobility models alone. In the
former case the solution does not fit well the distributed nature of the
network while, in the latter case, the quality of the solutions obtained for
realistic mobility models severely differs from the results obtained for
theoretical models. The rationale of this paper is inspired by the observation
that re-encounters of mobile nodes do elicit a form of social ties. Leveraging
these ties, it is possible to design efficient and distributed algorithms that,
with a moderated degree of node cooperation, enforce the emergent property of
node capture detection. In particular, in this paper we provide a proof of
concept proposing a set of algorithms that leverage, to different extent, node
mobility and node cooperation--that is, identifying social ties--to thwart node
capture attack. In particular, we test these algorithms on a realistic mobility
scenario. Extensive simulations show the quality of the proposed solutions and,
more important, the viability of the proposed approach.
