2015 1 st International conference on futuristic trend in computational analysis and knowledge management (ABLAZE 2015) 475 Securing TORA against Sybil Attack in MANETs Suraj Thawani Hardik Upadhyay Department of Wireless and Mobile Computing Department of Computer Science & Engineering GTU PG School GPERI Ahmedabad, India Ahmedabad, India surajthawani5262@gmail.com hardik31385@gmail.com Abstract - Mobile Ad-hoc Network (MANET) is a quite challenging to ensures security because if it’s open nature, lack of infrastructure, and high mobility of nodes. MANETs is a fast changing network in a form of decentralized wireless system. It requires a unique, distinct and persistent identity per node in order to provide their security and also has become an indivisible part for communication for mobile device. In this phase of dissertation, we have focused giving security to Temporally Ordered Routing Protocol Algorithm (TORA) from Sybil attack. TORA is based on a family of link reversal algorithm. It is highly adaptive distributing routing algorithm used in MANET that is able to provide multiple loop-free routes to any destination using the Route Creation, Route Maintenance and Route Erasure functions. Sybil attack is a serious threat for wireless networks. This type of attacker comes in the network and they start creating multiple identities. From that multiple identities they are disrupting the network by participating in communication with line breaking nodes. This cause huge loss in network resources. These networks can be protected using network failure and firewall detection schemes for detecting the attack and minimizing their effects. Proposed approach is expected to secure TORA through the implementation. Performance factor of network would be taken into consideration in order to verify the efficiency of modified TORA in MANET environment. Keywords— Mobile Ad-hoc Networks, TORA, Security, and Sybil Attack. I. INTRODUCTION A. Mobile Ad-hoc networks A mobile ad-hoc network (MANET) is a non-aligned system of mobile routers and hosts connected by wireless links [1]. These nodes includes laptop, computer and wireless phones etc., have a limited conveyance range. The routers are free to move randomly because it is a self-configuring infrastructure less network of mobile device connected by wireless. Thus, the network is wireless topology that may change rapidly and randomly. These networks are erect, work and maintained by its own because each node performs two role, one for router and one for host. In MANET, each node search for the support of its neighboring nodes to forward packets in a peer-to-peer fashion with no cluster architecture. Because of this, most of protocol except that other nodes are trustable reliable, so they do not consider the security and attack issues. In this, it is hard to determine which node has really leaved the network, location changed or it has been blocked or intercepted. B. Routing Protocols in MANETs Routing protocols for mobile ad-hoc networks (MANETs) can be broadly classified into Reactive (on-demand) routing protocol, Proactive routing protocol and Hybrid protocols. A routing protocol are used to discover routing path between all the nodes [2]. In proactive routing protocols, nodes in the network are continuously maintains up-to-date routes to every other node. To maintain routing table unity, routing information is periodically transmitted throughout the network. If a route has already existed before traffic reaches then communication occurs without delay. If destination node doesn’t receives routing information, till then traffic packets should wait in queue for the other node [3]. In contrast to proactive approach, in reactive protocols when the node wants to send the packets to the destination then only route discovery is used in the network. In the network, a node initiates a route discovery process is used. If route discovery process is completed once a route and all possible transformation have been survey then the route is maintained by the route maintenance process [3]. Figure 1: MANET Routing Protocols II. TEMPORALLY ORDERED ROUTING PROTOCOL ALGORITHM (TORA) Temporarily Ordered Routing Protocol (TORA) is a distributed routing algorithm that is based on a family of link reversal algorithms [4]. It is able to provide multiple loop-free routes to any destination on-demand. TORA tries to gain a high degree of scalability using a flat and non-hierarchical routing algorithm. At destination, Directed Acyclic Graph (DAG) is routed which builds and maintains. Information may flow from higher height to the lower height of nodes. The 978-1-4799-8433-6/15/$31.00©2015IEEE