Security challenges in mobile ad hoc networks:a survey <s> INTRODUCTION <s> Over the years, the usefulness of wireless mobile ad hoc networks has been well documented. In the recent times, a lot of effort has gone into the study of the integration of mobile ad hoc networks and the Internet. This paper discusses the challenges of connecting mobile ad hoc networks to the Internet. Next, it reviews the characteristics of ten proposed solutions with their relative merits and de-merits in the light of a few specific parameters. It concludes with a discussion on the suitability of the solutions under different scenarios. <s> BIB001 </s> Security challenges in mobile ad hoc networks:a survey <s> INTRODUCTION <s> This paper presents two novel mechanisms for the OLSR routing protocol, aiming to improve its energy performance in Mobile ah-hoc Networks. Routing protocols over MANET are an important issue and many proposals have been addressed to efficiently manage topology information, to offer network scalability and to prolong network lifetime. However, few papers consider a proactive protocol (like OLSR) to better manage the energy consumption. OLSR presents the advantage of finding a route between two nodes in the network in a very short time, thanks to its proactive scheme, but it can expend a lot of resources selecting the MultiPoint Relays (MPRs) and exchanging Topology Control information. We propose a modification in the MPR selection mechanism of OLSR protocol, based on the Willingness concept, in order to prolong the network lifetime without losses of performance (in terms of throughput, end-to-end delay or overhead). Additionally, we prove that the exclusion of the energy consumption due to the overhearing can extend the lifetime of the nodes without compromising the OLSR functioning at all. A comparison of an Energy-Efficient OLSR (EE-OLSR) and the classical OLSR protocol is performed, testing some different well-known energy aware metrics such as MTPR, CMMBCR and MDR. We notice how EE-OLSR outperforms classical OLSR, and MDR confirms to be the most performing metric to save battery energy in a dense mobile network with high traffic loads. <s> BIB002 </s> Security challenges in mobile ad hoc networks:a survey <s> INTRODUCTION <s> Recently, because of the rising popularity of multimedia applications and potential commercial usage of MANET(Mobile Ad Hoc Network)s, and the limited bandwidth and dynamic topology in MANETs. providing required bandwidth for these applications in MANETs has become an unavoidable and urgent task to achieve sufficient QoS (Quality of Service). Time slot assignment is essential to provide the calculated bandwidth in TDMA (Time Division Multiple Access)-based MANETs, which are a focus of attention of this paper because of its collision-free packet transmission with QoS support. In this paper, a new time slot assignment algorithm-PBTSA (Policy-Based Time Slot Assignment) is proposed, by which more available bandwidth can be obtained than conventional approximate solutions. In addition, PBTSA's effectiveness is proved by simulation results. <s> BIB003 </s> Security challenges in mobile ad hoc networks:a survey <s> INTRODUCTION <s> Sometimes the physically distributed computing devices in a network may be interested in computing some function of their private inputs without disclosing these inputs to one another. This type of computation falls under the category of Secure Multiparty Computation (SMC). The solution to SMC problems in Mobile Ad hoc Networks (MANET) can be found with the modification of the data inputs or with some anonymization technique. MANETs are the wireless networks of the mobile computing devices with no support of any fixed infrastructure. The mobile nodes use any of the radio technology like Bluetooth, IEEE 802.11 or Hiperlan for directly communicating with each other. The nodes behave as hosts as well as routers. The security challenges in the MANET arise due to its dynamic topology, vulnerable wireless link and nomadic environment. An identification mechanism is needed between the nodes using identification and the credentials. This security architecture simultaneously leads to privacy problems. Some mechanism is needed which prevents a node to learn the identity or the credentials of other nodes. To provide location privacy in MANET is a nontrivial task. Current routing protocols do not focus much on the security and the privacy issues. These aspects are postponed till further development. An authentication protocol is needed between nodes using some cryptographic technique. In service-oriented MANET the denial of the service must be taken care of so that the availability of the service is maintained. The security requirement of the ad hoc network depends on its application. For example, for a simple business meeting the requirement is mitigated and for the military battlefield it is severe. Thus no general security architecture can be developed for MANET. Specific security architecture is needed for specific application. Much security related work is still pending and will add to the standards as the physical deployment of the MANET will grow. In this paper, an emphasis is made on how SMC solutions can be used for privacy preservation during computation. <s> BIB004 </s> Security challenges in mobile ad hoc networks:a survey <s> INTRODUCTION <s> MANETs are an ideal technology to deploy spontaneous wireless infrastructure-less networks, either for military or civilian applications. The absence of centralized administration and infrastructure-less nature gives rise to authentication and key management problems in the MANETs. Recently, several approaches have been proposed for the authentication mechanisms. Among of them, certificate chain based authentication mechanism better suits the MANET environment due to its self-organization nature. However, an unstable topology and link failure which is quite common in MANET pose a greater challenge to the certificate chain mechanism. To overcome this, we propose a stable certificate chain based authentication mechanism for MANET. Here, the route selection algorithm incorporates the Link Expiry Time which helps in selecting links for authentication and data communication. This enhances the stability of the certificate chain which in turn provides enhanced security. It has been found that the proposed scheme decreases the number of path changes and the time taken for authentication. Simulations done in NS2 (Network Simulator tool) gives better performance in terms of standardized parameters such as Routing Overhead, Packet Delivery Ratio, End-to-End delay and Time Taken for Authentication in comparison with the existing certificate chain mechanism. <s> BIB005 </s> Security challenges in mobile ad hoc networks:a survey <s> INTRODUCTION <s> Although topology control has received much attention in stationary sensor networks by effectively minimizing energy consumption, reducing interference, and shortening end-to-end delay, the transience of mobile nodes in Mobile Ad hoc Networks (MANETs) renders topology control a great challenge. To circumvent the transitory nature of mobile nodes, k-edge connected topology control algorithms have been proposed to construct robust topologies for mobile networks. However, uniformly using the value of k for localized topology control algorithms in any local graph is not effective because nodes move at different speeds. Moreover, the existing k-edge connected topology control algorithms need to determine the value of k a priori, but moving speeds of nodes are unpredictable, and therefore, these algorithms are not practical in MANETs. A dynamic method is proposed in this paper to effectively employ k-edge connected topology control algorithms in MANETs. The proposed method automatically determines the appropriate value of k for each local graph based on local information while ensuring the required connectivity ratio of the whole network. The results show that the dynamic method can enhance the practicality and scalability of existing k-edge connected topology control algorithms while guaranteeing the network connectivity. <s> BIB006
In these years, progresses of wireless technology and increasing popularity of wireless devices, made wireless networks so popular. Mobile Ad Hoc Network (MANET) is an infrastructureindependent network with wireless mobile nodes. MANET is a kind of Ad Hoc networks with special characteristics like open network boundary, dynamic topology, distributed network, fast and quick implementation and hop-by-hop communications. These characteristics of MANET made it popular, especially in military and disaster management applications. Due to special features, wide-spread of MANET faced lots of challenges. Peer to peer applications  , integration with internet BIB001 , security BIB005 , maintaining network topology BIB006 and energy BIB002 BIB003 are some of the most important challenges in MANET. We presented an analysis and discussion in MANET challenges in our previous work  . In MANET all nodes are free to join and leave the network, also called open network boundary. All intermediate nodes between a source and destination take part in routing, also called hop-byhop communications. As communication media is wireless, each node will receive packets in its wireless range, either it has been packets destination or not. Due to these characteristics, each node can easily gain access to other nodes packets or inject fault packets to the network. Therefore, securing MANET against malicious behaviours and nodes, became one of the most important challenge in MANET BIB004 . The aim of this paper is to provide a brief discussion and analysis on MANET security. Based on MANET characteristics we defined three important security parameters for MANET. In addition, two different aspects of MANET security are discussed in details. Furthermore, we presented an analysis and discussion in security attacks and defeating approaches. Moreover, the most effective defeating approaches for MANET and their limitations are introduced. Finally, some research directions are discussed. Rest of this paper is organized as follow: in section 2, three important security parameters in MANET are presented. Section 3 presents two important aspects of security with a discussion on their strategies. Three combinational challenges with security are presented in section 4. Section 5 presents our analyses and classifications on security of MANET and presents some research interest in security. Section 6 introduces open research issues and directions of researches in MANET security. Finally section 7 concludes the paper and introduces best ways to secure MANET and presents some future works.