الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Mobile Ad Hoc Network (MANET) is a self organizing network, where a collection of
mobile nodes form a temporary network without using any xed infrastructure. So each
node can participate as a mobile router to choose optimal route and as intermediate
node to forward data to the other nodes through wireless radio signals. As a result,
MANET can be widely used in several applications which has lack of infrastructure.
The main features of these networks such as ever-changing topology, shared wireless
medium and the lack of xed infrastructure make MANET more vulnerable to several
attacks like identity spoo ng and trac analysis which lead to identity disclosure. Se-
curing identity is an important issue for keeping the privacy of the nodes, as identity
plays an important role in di erent network services.
As identity protection in the challenging MANET’s environment has received an in-
creasing research interest. The literature shows that there are several rehearsals in this
regard. Anonymous routing protocols are the most popular solutions in the literature,
that keep the identity of the users anonymous during the communication. However,
these solutions are limited on certain routing protocols and can be applied on network
layer only.
The represented work in this thesis is oriented to achieve scalable identity protection in
MANETs. For identity protection, the thesis presents a light generic IP-Based scheme
(GPSIH) for protecting identity of the mobile nodes through applying encryption tech-
niques. The proposed scheme can be implemented in the network layer regardless of
the applied routing protocols. It can be also integrated easily to lower network layers
like MAC layer and the higher layers as well. GPSIH is a centralized approach based
on distributing a security key that is periodically updated among mobile nodes through
central entity. The simulation studies proved that GPSIH was performing well in the
presence of malicious nodes for low scale networks. However, GPSIH cannot handle key
distribution issues that may arise in dense networks.
In order to avoid centralization problem for key distribution and achieve scalability for
large networks, a key distribution scheme for clustered ad-hoc networks is proposed
(C-GPSIH). The network is divided into groups of clusters and each cluster head is re-
sponsible for distributing periodically updated security keys among cluster members, for
protecting privacy through encryption. Moreover, an authentication scheme is proposed
to ensure con dentiality of new members to the cluster. The simulation study using
OPNET modeler proves the e ectiveness of the proposed scheme in terms of availability
and overhead. It scales well for high dense networks, and gives less packet DROP rates
compared to its centralized counterpart in the presence of malicious nodes.