الفهرس 
Ad-hoc Security Survey Based on Key ManagementOnly 14 pages are availabe for public view
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Abstract
Security is one of the major issues in Mobile Ad-hoc Networks (MANETs). Their natural characteristics make them vulnerable to numerous severe attacks. In this thesis, we present an enhanced hierarchical key management scheme (EHKMS) for secure group communications in MANETs. The proposed approach primarily aims at improving security and complexity, especially complexity in the level of ordinary members for joining or leaving processes to achieve the most possible dynamic characteristic of mobile ad-hoc networks and highly node mobility without neglecting network security. The proposal EHKMS is designed with the potential of developing an effective model interested in keying scheme applied on hierarchical structure that lead to increase the security and make no need to apply rekeying of all group members or rekeying of nodes in different sub-levels as made by traditional hierarchical key management scheme (HKMS) and to reduce complexity of processing load, memory usage and improve resources. In the proposal EHKMS model, each communication between two nodes has a unique key that makes it more secure with encrypting messages by different keys for more than one time and support node flexibility. Representing the mathematical model are carried out for the proposed scheme to show the effect of complexity on each node in different grades and the obtained results are compared with traditional HKMS. The proposal EHKMS decrease complexity in level of ordinary nodes that makes high value of node mobility and fixed it in level of L2-head and make easy to build the hierarchal with secure key system. The proposal EHKMS suffers from only final problem which is intrusion attack that may appears in two aspects frank intrusion and selfish attack which threatens the security of the system. So, there is a need for some developments on the proposal EHKMS to overcome these problems. Firstly, intrusion may try to hear or eavesDROP packets during transmissions by impersonating a node in the scheme and trying to establish connection with other nodes to perform its attack. Secondly, the intrusion attack may be occurring in the shape of passive eavesdropping as well as active message insertions, denial of service, denial of resources, battery-exhaustion or denial of power and all of these attacks disrupt or hinder ad-hoc network performance. So, it is necessary to develop a new mechanism to stop these attacks. In this thesis, efforts have been made to overcome intrusion attacks in EHKMS by applying three phase techniques over EHKMS to allow EHKMS to perform certification authentication security system beside key security to solve previous problems.