Simulation of A Novel Scalable Group Key Management Protocol for Mobile Adhoc Networks

A Mobile Adhoc Network (MANET) is a collection of autonomous nodes that communicate with each other ,most frequently using a multi-hop wireless network. Secure and multicast group communication is an active area of research in MANETS. The main problem in secure group communication is group dynamics and key management. Group key management is crucial for multicast security. Member joining and member leaving from the group is the main challenge in designing secure and scalable group communication for dynamic update of keys. Most of the proposed solutions for wired networks are not considering this parameter and so suffer from the one-affects-n scalability problem. This paper presents the simulation of A Novel Scalable Group Key Management Protocol (NSGKMP) for wireless Adhoc Networks and demonstrates the simulation results through NAM(Network Animator) in NetworkSimulator2 (NS2). This NSGKMP for MANETs approach decreases number of rekeying operations when a member joins in to the group or leaves from the group i.e. dynamic updating of keys. KeywordsMANET, NSGKMP, NAM, Rekeying, join and leave . I.INTRODUCTION Mobile Ad-hoc Network (MANET) is a collection of self-configurable nodes or terminals which communicate with each other by forming a multi-hop radio network and maintaining connectivity in a decentralized manner. Many applications of adhoc networks involve collaborative computing among a large number of nodes and are thus group-oriented in nature. The conventional security solutions to provide key management through accessing trusted authorities or centralized servers are infeasible for this new environment since Mobile Adhoc Networks are characterized by the absence of any infrastructure, frequent mobility, and wireless links. In wired networks, many group key management protocols have been proposed and simulated[6,7],Efficient Group key(EGK), Tree Group Diffie-Hellman (TGDH), Logical key hierarchy(LKH),Skinny TRee (STR) and Computation and Communication Efficient Group Key (CCEGK) . However, these approaches are not directly applicable to ad hoc networks, because the communication cost per node can become very high for a large adhoc network with very dynamic group membership. So far very few group rekeying schemes have been proposed for ad hoc networks. They either use public-key techniques [8], or adapt the LKH scheme for ad hoc networks [9]. Public-key based schemes [8] are more expensive than symmetric-key based schemes in both communication and computation. The adapted LKH scheme [9] incurs the computational and communication cost that is of the same order as the LKH scheme . In this paper, we present the simulation of a Novel Scalable Group Key Management Protocol(NSGKMP) for Wireless Mobile Adhoc Networks. In NSGKMP protocol, other than secure group communication forward secrecy and backward secrecy are maintained among the nodes. Forward secrecy prevents an accessing current communication by old member after it leaves from the group. Backward secrecy prevents an accessing of the communication sent before a new member joins to the group. To do so, a re-keying process should be performed after every join or leaving a member from the secure group. It consists in generating a new TEK and distributing it to all group members. The main problem with any re-keying technique M. Sandhya Rani et al. / International Journal on Computer Science and Engineering (IJCSE) ISSN : 0975-3397 Vol. 8 No.3 Mar 2016 70 is scalability: as the re-keying process should be performed after every member join or leave from the group. The computational and communication overhead induced may be important in case of frequent join and leave operation to group. NSGKMP for MANETS is based on the Chineese Remainder Theorem and a hierarchical graph BTree,in which each node contains two keys and a modulus[2,3]. The previous approach [2] is concentrated on to decrease number of re-keying operations, i.e. from to when compared with [3], where n is the number of leaf nodes of tree and m is the order of the B-Tree. Here we are taken order of B-Tree is 3(i.e. m=3).In [1], NSGKMP for wired networks has been simulated. This paper presents brief introduction to NetworkSimulator2 (NS2) and simulation of NSGKMP approach for MANETs with the help of NetworkSimulator2 (NS2) NAM. And we showed that number of rekeying operations are less in NSGKMP for MANETS than SGKMP[3] through NAM visualizations. The remainder of the paper is organized as follows. Section II presents Structure Of MANET nodes for Proposed Approach , Section III presents Simulation Environment, Section IV presents Simulation Results, Section V presents performance of the protocol and Section VI gives the conclusion. II. STRUCTURE OF MANET NODES FOR PROPOSED APPROACHS Several Group Key management schemes have been proposed with different network structures and topologies: random fashion, tree structure, hierarchical and hybrid[4,8].In this paper we present the B-Tree structure as shown in Fig. 1 for group communication to deploy the MANET nodes . In B-Tree of order m, each node contains at most m-1 elements and each node contains at least -1 elements. The Fig. 1 describes that a B-Tree of order 3, so each node consists of at most 2 elements, And maintaining users of the group at leaf nodes of B-Tree. So each leaf node consists of 2 users. i.e. node21 consists of user’s u1 and u2 , node22 consists of user’s u3 and u4 node29 consists of user’s u17 andu18 . In the Fig. 1 user u18 wants to join into the group. After joining in to the group to provide backward secrecy we are changing the parent’s key from leaf to the root node that was indicated in the Fig. 1. After changing the parent’s keys, the changed keys are sent to the corresponding children’s that was shown in the simulation. In [3], binary tree structure is used. When the group is large, the number of levels in the binary tree will be more which increases number of keys at member. Extending this scheme to B-Tree will reduce the height of the tree reducing number of keys at each member. At the same time we should consider server side storage i.e. number of keys at the level of the tree. In [3], keys are maintained by the every member in the tree, extending the scheme to B-tree will result in maintaining keys by the members of the B-tree (where m is the order of B-tree and n is the number of leaf nodes ). Fig. 1 Group Structure in B-Tree format III. SIMULATION ENVIRONMENT A.Simulation Model Our proposed protocol simulations have been carried out using Network Simulator version 2 (NS2.35) and its associated tools for animation and analysis of results.NS2 is an event driven network simulator tool. We chose a Linux platform i.e. UBUNTU 12.10, as Linux offers a number of programming development tools that can be used with the simulation process. NS-2 allows a user to emulate network traffic as it actually occurs on physical networks. We used ftp traffic for packet transmission to implement our proposed protocol. The software simulates switches, routers, connections and traffic sources of various kinds. Traditionally, NS2 is used to model new versions of communication protocols like Transmission Control Protocol (TCP) and Ethernet, and it can also model new forms of traffic generation, like the group key management simulation for M. Sandhya Rani et al. / International Journal on Computer Science and Engineering (IJCSE) ISSN : 0975-3397 Vol. 8 No.3 Mar 2016 71 wired and wireless networks. We analyzed our experimental results in NAM(Network Animator) trace file. To evaluate the performance of NSGKMP for MANETs, we find the Rekeying path and number of rekeying messages in a group of nodes through NAM animation . B. Simulation Parameters The simulation parameters used in our work are listed in Table 1. TABLE I. SIMULATION PARAMETERS