SECURITY ISSUES IN MOBILE AD-HOC NETWORK & SOLUTIONS
Ali Hussein Raheem, Post Graduate Student, Engineering and Information Sciences, Middlesex University
Abstract —Network has become a very important aspect in the technology development because it has the biggest effect on the communication between people, exchange and share resources. Network is a group of computers and other devices connected together in order to allow information to be exchanged or shared between each other. Having a high level of security in any system in network has become the desire that most of people want to reach. Therefore, the intention of this paper is to explore the security Issues in mobile Ad-hoc network. The paper has been divided into five impotent sections. The first section discusses the weaknesses or vulnerabilities in mobile Ad-hoc network. The second section mentions the types of Attack in mobile Ad-hoc network. The third discusses the routing protocols in mobile Ad-hoc network. Fourth, discusses the goals security of mobile Ad-hoc network. Finally, the paper will offer security solutions for mobile Ad-hoc network which can provide a high performance security to mobile Ad-hoc network.
Nowadays, network technology has many influences on peoples’ life to make exchanging information smoothest and seamless than before. However, there are three different types of networks such as APN, Wi-Fi, and Wi-MAX networks which all help people to exchange information and data between different places around the world. But unfortunately, some people use this technology to attack others’ devices; therefore security must come to stop and limit those attackers and keep the information secure and safety.
Ad-hoc network is a self configuring network of wireless (communication) which consists of connected mobile nodes that can be connected together either by routers or hosts. Mobile nodes can communicate with each other directly without any access point. This means that there is no fixed infrastructure and routers have the ability to move randomly without any restrictions; they can position themselves as it is required. Each node of the mobile devices has a transmitter and a receiver. In other words, mobile Ad-hoc network (MANET) has a system of wireless node which is dynamically self-organized. Moreover, mobile Ad-hoc network nodes can communicate directly with other nodes which they are in their radio ranges so if the node has an indirect commutation range, it will use other nodes to make the communication with them. Ad-hoc networks have different types of features as follows
Firstly, Ad-hoc network is an unreliable wireless link between the nodes. This means that there is a limited power supply for wireless node and the mobility of the node.
Secondly, the routing information (data) can be changed because of the nodes movement .This means that the nodes have the ability to move inside or outside the radio range of the nodes in mobile Ad-hoc network.
Thirdly, in mobile Ad-hoc network, nodes have the ability to move and change their places constantly. And this might be the cause why the nodes can be easily attacked .To prevent such attacks, nodes need to be incorporated within the routing issue which can prevent some kind of potential attacks in mobile Ad-hoc network.
Figure 1shows Mobile Ad-hoc network without any access point.
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Figure 1mobile Ad-hoc network
Undoubtedly, these hindering features cause many problems to the mobile Ad-hoc network and make it liable to suffer from some malicious behaviors which are uncommon with the traditional wired networks. Consequently, this paper will focus on five main sections. The first section will discuss the weaknesses or vulnerabilities of mobile Ad-hoc network. The second section will mention the different types of Attacks in mobile Ad-hoc network. The third section will discuss the routing protocols in mobile Ad-hoc network. As for the fourth section, it will discuss the security goals of mobile Ad-hoc network. The paper will attempt finally to suggest some solutions for mobile Ad-hoc network which can provide high performance security to mobile Ad-hoc network. 
II. VULNERABILITIES of the mobile Ad-hoc network
Before suggesting solutions for the security problems in mobile Ad-hoc network, it is necessary first to understand the vulnerabilities of this network and the difficulties that usually affect the performance of the mobile Ad-hoc network .To begin with, the heaviest elements of these weaknesses that actually minimize the efficiency of the Ad-hoc network are five in number. 
Firstly, the lack of secure boundaries in mobile Ad-hoc network is the major deficiency and simultaneously the biggest difference from the wired traditional network which has a solid line defense that can protect it from any attacks. As a matter of fact, this vulnerability in mobile Ad-hoc network is originated from the exact nature of the structure of mobile Ad-hoc network .more specifically the nodes themselves are able to move inside the network and leave their places freely and haphazardly. On the other hand, to get access to the wired network means that the user needs to pass through different kind of protection walls such as firewall and gateway. Whereas in mobile Ad-hoc network, there is no need for adversary to gain the physical access to the network. This facility gives mobile Ad-hoc network the ability to communicate easily with any nodes within the radio range of the network and this in turn makes it easy for joining the network nodes and letting these nodes to communicate with each other automatically. It can be realized that mobile Ad-hoc network does not provide high performance quality of secure boundary .In this sense ,it is quiet incapable of protecting the network from any potential danger of access attacks. Subsequently, this might affect the network negatively. For example, it might affect devastatingly the transmitted data either by destroying the secret information or even sending virus messages.  
Secondly, threats come from compromised nodes themselves inside the network .This means that similar attackers try to gain control over nodes by using the nodes themselves to have the power over the network or to do bad actions. As it has been mentioned before, those nodes inside mobile Ad-hoc network have the ability to leave their places and move inside the network freely without any boundaries .In this way, it is difficult to set the malicious behavior or specify which node has been attacked .Again; this problem makes it indeed difficult for the user to trust any node. 
Thirdly, the lack of centralized management facility is another problem encountered by the security performance mechanism in mobile Ad-hoc network because unfortunately mobile Ad-hoc network does not have any centralized piece of management. The missing centralized management machinery makes it indeed very hard for the network to detect attacks and even difficult to control or monitor the traffic in high dynamic performance .This problem causes in turn breakdown and failure of the transmitted data. Furthermore, in mobile Ad-hoc network, it is not required from the node to cooperate in network operation .This means that there is no involvement of these nodes in any security operation; a deficiency that marks the blatant difference between the mobile Ad-hoc network and the wired network .The latter has both a line defense and the ability to set which of the nodes can be trusted and which are not, a technique that is completely lacking and missing in mobile Ad-hoc network .A shortage of this kind affect directly all operations of mobile Ad-hoc network especially when there is any serious attack faced by any node.