Secure Self Re-Organizing of Nodes Using Closeness Technique in Cluster MANET

Mobile ad hoc network (MANET) is defined as a self-configuring infrastructureless network used for communication by wireless links with the support of mobile devices. A MANET is referred to as a wireless network with independent nodes moving freely with respect to each other. Due to the independent free moves of nodes, a huge amount of packet data loss occurs in transmitting the packet from source to destination. The risk of node misbehaviour is extremely high. The unsecured ad hoc network environment is initiated due to the active nature of networks and node mobility. In addition, the task of key management is more complex in ad hoc network. Due to the nature of free moving characteristics, MANET faces improper node cooperation. The main reason behind ineffective node cooperation is presence of malicious or selfish nodes. Moreover, the existence of malicious unauthenticated nodes causes insecure communication. Hence, the proposed system aims in the development of proper node cooperation, malicious node detection and secure communication in MANET.

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Chapter 3.2 SECURITY ISSUES IN MANET:
Wireless networks provide connection flexibility between users in different places. In addition, the network can be extended to any place or building without the need for a wired connection. Wireless networks are differentiated into two classification namely infrastructure networks and ad hoc networks. An Access Point (AP) acts as an essential coordinator for all nodes in infrastructure networks. The nodes are linked to the network with the support of access point. In addition, AP systematizes the connection between the Basic Set Services (BSSs), facilitating easy access of route at the time of requirement. But the limitation of handling infrastructure network is the huge volume of the routing table. Additionally, the AP is connected to the router through wire in infrastructure environment leading to unsecure communication. [...].
Figure 3.1 describes the types of wireless network communication. The dotted line represents wireless connection and the solid lines represent wired connection. The two different types of wireless communications are wired AP connection with wireless nodes and complete wireless node connection. The purpose of AP is to coordinate the nodes for better communication and to support transmission as AP is connected to router/hub. On the other hand, the complete wireless node connections are connected to mobile devices. Moreover, the possibility of attack is high on communication between mobile device and nodes. Additional concentration is required in complete wireless node connections.
Unlike in infrastructure network a central coordination point is needless in ad hoc network. Moreover, sending and receiving packets are denser than infrastructure networks. Currently, with the enormous development in wireless network applications like PDAs and cell phones, handheld computers, researchers are optimistic to progress the network services and routine. One of the demanding proposal issues in wireless ad hoc network is supporting secure mobility in MANET. The independent behavior of nodes in MANET enhances the difficulty of the routing protocols and the amount of connection flexibility. But, the possibility of permitting nodes to connect, depart, and transfer data to the network cause security challenges.
In a wireless network, a transmission range of node usually uncovers the entire network, so end-to-end communication requires routing information through some nodes. As a result, ad hoc networks are referred to as multi-hop networks. The hop is a direct link between two nodes. In an ad hoc network, nodes are termed as routers or terminals. As ad hoc network is an environment without infrastructure, the co-operation among the routers is worst. Independent nature of nodes creates the problem of routing framework leading to nodes misbehavior in the network. The misbehaved node types are referred to as selfish nodes. The lifespan of the network automatically decrease when the selfish nodes in the network increases. The main solution to address these problems is providing secure routing.
Fadlullah et al (2010) proposed techniques for securing routing in ad hoc network such as Certificate-Based Cryptography (CBC) and ID-Based Cryptography (IBC). For a fixed network, a secure communication is effectively done through Public Key Infrastructure (PKI) or a centralized certification authority. But these methods are not feasible for ad hoc network. Distribution of a signing key and Centralized Authority (CA) functionality over multiple nodes is a promising solution to this problem. In ad hoc network, the reputation mechanism is presented to dynamically evaluate the authentication of neighboring nodes. The reputation system selects the trusty nodes to support trustworthy behavior in transferring packets.
The three main goals of reputation system are providing useful information about the authenticated and unauthenticated nodes in the network, encouraging the authentica