International Journal of Emerging Technology and Advanced Engineering Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 3, Issue 3, March 2013) 360 An Efficient Wormhole Prevention in MANET Through Digital Signature Anil Kumar Fatehpuria 1 , Sandeep Raghuwanshi 2 1 M.Tech Scholar, 2 Assistant Professor, Samrat Ashok Technological Institute,Vidisha (M.P.), India Abstract— Wireless networks are gaining popularity to its peak nowadays, the desire to be connected anytime and anywhere has led to the development of wireless network, opening new vista of research in pervasive and ubiquitous computing. Mobile Ad hoc Network (MANET) has distributed mobile wireless nodes, which do not have pre-determine topology and pre-existing infrastructure mobile nodes that can arbitrarily change their geographic locations and random mobility with constrained resources, ad hoc networks are vulnerable due to their structure less property. During the wormhole attack, a malicious node captures packets from one location in the network, and “tunnels” them to another malicious node at a distant point, which replays them locally. We identify two types of wormhole attacks. In the first type, malicious nodes do not take part in finding routes, meaning that, legitimate nodes do not know their existence. In the second type, malicious nodes do create route advertisements and legitimate nodes are aware of the existence of malicious nodes, just do not know they are malicious. Some researchers have proposed detection mechanisms for the first type. In this paper we represent a mechanism which is helpful for prevention of wormhole attack, through observing the delay of different path to receiver and verification of digital signature. Our mechanisms detect pinpoint location of wormhole and prevent them. This method requires neither synchronized clocks nor special hardware equipped mobile nodes. Keywords- MANET, Wormhole Attac Detection & Prevention, Digital Signature , Multipath Hop Count Analysis. I. INTRODUCTION Mobile Ad Hoc Networks are formed by a set of hosts that communicate with each other over a wireless channel. Each node has the ability to communicate directly with another node (or several of them) in its physical neighbourhood. Such mobile Ad Hoc Networks have many attractive features including automatic self-configuration and self-maintenance, quick and inexpensive deployment, and the lack of the need for fixed network infrastructures or centralized administration [1],[2].These features lead to important applications that can not be Performed by traditional wired networks. The importance of mobile Ad Hoc Networks is increasing rapidly with advances in technology that result in smaller, cheaper, and power- efficient devices . On the other hand, MANET utilizes an untrusted environment for data transmission, and therefore it is subjected to various kinds of security attacks [2]. Figure1. Mobile Ad Hoc Network Mobile ad hoc networks have following features [3]:  The wireless link between the nodes is highly vulnerable. This is because nodes can continuously move causing the frequent breakage of the link. The power available for transmission is also strictly limited.  The topology of the network is highly dynamic due to the continuous breakage and establishment of wireless link. Nodes continuously move into and out of the radio range. This gives rise to the change in routing information.  These is a bandwidth constraint in this wireless networks.  MANETS need energy - efficient operation because all the nodes depend on battery power which is highly limited. The open nature of the wireless medium makes it easy for outsiders to listen to network traffic or interfere with it. These factors make ad hoc network potentially vulnerable to several different types of malicious attacks. Like Wormhole Attack, Block Hole Attack, Rushing Attack etc [1] and [5].