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Abstract:In vehicular Ad hoc Networks, the privacy protection is one of the major requirements. Since there are huge number of vehicles on our highways and city roads there must be possibility of attacks. To protect the privacy of vehicles, one solution is to hide the vehicle’s identity with the use of pseudonym keys (i.e, temporary identities). Each vehicle uses its pseudonym key to communicate with other vehicles and road side units. The main effort of this work is to provide a solution towards privacy protection in vehicular Ad hoc Networks. Initially, we view vehicular ad hoc networks having non-overlapping sub networks referred to be a cell. Each cell with small geographic area having a pseudonym server which generates a list of pseudonyms using capacity planning algorithm. The Diffie Hellman Key Exchange scheme is also used to increase privacy protection. Our another effort is to reduce the routing overhead by using Hybrid Location based Ad hoc Routing (HLAR) protocol for routing pseudonyms and further communication. The accurate results are obtained and the performance is compared with reactive by detailed simulations.
Keywords::Vehicular Ad hoc Networks, Hybrid Location based Ad hoc Routing, Diffie Hellman Key Exchange, and privacy.
1. Introduction
Vehicular ad hoc networks (VANETs) are highly mobile wireless network technology that is implemented to help traffic monitoring, vehicular safety, and other commercial applications. A vehicular ad hoc network uses moving vehicles as nodes in a network in order to create a mobile network. An accurate position of vehicles can be estimated by using global positioning systems or on-board sensors. VANETs are used for short range, high-speed communication among nearby vehicles, and between vehicles and roadside infrastructures.
Within VANETs, there are huge number of vehicles on our highways and city streets, leads to possibilility of severe attacks and routing overhead [6]. So the scalable and robust privacy protection must be needed. In this paper, the Diffie Hellman Key Exchange technique is used in order to improve privacy protection especially solves man-in-the-middle-attacks. Then the routing overhead is also reduced by using hybrid location based Ad hoc routing.
2. Related Works
2.1. A Certificate Authority and Reactive Routing Based Privacy
There are many challenges for the protection of privacy in vehicular ad hoc networks due to large mobility, to the characteristics of traffic flow, to the correlation among each vehicle and its driver, and to the high population of vehicles. The scalability and robustness are promoted by employing a combination of two strategies. First, the vehicular networks are viewed as non-overlapping sub networks and each local to a geographic area referred to as a cell. Depending on the topology and the nature of the area, these cells may be as large as few city blocks or, indeed, may comprise the entire downtown area of a smaller town. Each cell has a server that maintains a list of pseudonyms that are valid for use in the cell. Each pseudonym consists of the cell‘s ID and of a random host ID. The public and private keys of each vehicle
CSE140401 www.ijicse.com
International Journal of Inventions in Computer Science and Engineering ISSN (Online): 2348 – 3539, ISSN (Print): 2348 – 3431
Volume 1 Issue 3 2014
and infrastructure are assigned and maintained by a Certificate Authority (CA) [1]. Also, instead of issuing pseudonyms to vehicles proactively, as virtually all existing schemes do, the pseudonyms are issued to those vehicles that need them, and also request them. Prior to communicating with either the infrastructure or with other vehicles in the cell, vehicles need to request pseudonyms from the cell server. The pseudonyms are intended to hide the real identity of vehicles, either their host name, or IP address.
2.2. A Scalable Robust Authentication Protocol Based Privacy
A decentralized authentication protocol uses RSUs to maintain a group within their communication range, which is normally much longer than the V2V communication range, is used. Vehicles can anonymously broadcast V2V messages that can be verified by other vehicles in the group and neighboring groups. In this system, vehicles only request a new secret member key when they pass by an RSU for the first time or when their existing secret member keys expire. Since each vehicle only verifies messages from vehicles that have moved into the range of the same RSU and its neighbors, it can easily check whether the anonymous sender was revoked with the help of those RSUs and does not need to retrieve the revocation list from a remote centralized authority. This greatly reduces the certificate management overhead [4]. Although each party in this system needs a secret member key, the system‘s master key is only known and stored by a centralized authority, rather than being stored in each tamperproof device that is embedded in vehicles.
2.3. Symmetric Random Keyset Based Privacy
A group based privacy preserving authentication protocol for vehicular networks is used. A symmetric random key set is used for anonymously privacy-preserving authentications in vehicular networks. The random keyset based authentication protocol that preserves user privacy under the zero-trust policy, in which no central authority is trusted with the user privacy is used. In the zero-trust policy, vehicles trust neither public nor private servers nor networks [2]. The privacy-preserving authentication protocol can efficiently authenticate users without compromising their privacy using malicious user identification and key revocation. The privacy-preserving authentication protocol can efficiently authenticate users without compromising their privacy using malicious user identification and key revocation. This system also takes the advantage of the shared keys between different random sets to achieve anonymity. The anonymity is further enhanced by using independent keys for authentications at neighboring RSUs. This system also takes the advantage of the shared keys between different random sets to achieve anonymity. The anonymity is further enhanced by using independent keys for authentications at neighboring RSUs.
3. System Design and Implementation
3.1. Design Criteria
The Network Simulator version 2.32 is chosen to simulate VANET and evaluate the protocols. It is an object oriented, discrete event driven, open source network simulator. It has notable advantages when compared to other simulators. In VANETs, the number of nodes can exceed several thousands and it has more efficient routing tables, which can be easily simulated. It is easy to debug errors. It is a binded model between c++ and OTCL. Wireless network performance mainly depends upon end to end throughput and average delay. It is cost effective of network deployment as wiring is not possible.
3.2. Protocols and Algorithms Chosen 3.2.1. HLAR Protocol
A hybrid location-based ad hoc routing (HLAR) protocol combines a modified AODV protocol with a greedy-forwarding geographic routing protocol. HLAR protocol has the features of reactive routing with location-based geographic routing. It efficiently make use of all the location information available, to minimize the routing overhead, and to gracefully exit to reactive routing as the location information degrades [3]. Each node will have two separate tables, which were locally constructed from the beacon packets: 1) a neighbor table, which will be used to perform geographic routing, and 2) an ―ETX‖ table,
CSE140401 www.ijicse.com
International Journal of Inventions in Computer Science and Engineering ISSN (Online): 2348 – 3539, ISSN (Print): 2348 – 3431
Volume 1 Issue 3 2014
which will be used to construct the AODV route (the AODV routing table) upon request to obtain optimal scalability performance.
3.2.2. Diffie Hellman Key Exchange
The Diffie Hellman Key Exchange Scheme establishes shared secret key among unknown vehicles over an insecure communication medium [4]. It improves privacy protection in wireless networks especially the passive attacks.
3.2.3. Capacity Planning Scheme
A capacity planning scheme allows system servers to predict, by taking into account the time-varying attributes of the traffic, the probability that a given number of pseudonyms will be required at a certain time as well as the expected number of pseudonyms in use in a cell at a certain time [1]. Based on the prediction, the pseudonym server generates pseudonyms for a cell at a time.
4. Simulation
The simulation is done by using a Network Simulator version 2.32 software. Initially the nodes are designed as per the requirement. In this simulation we have designed 19 nodes. The nodes are the vehicles that take part in communication. They transmit packet among themselves. The coverage area of each node is 100m. Then the nodes are register to the Vehicular Ad hoc Networks. In Vehicular Adhoc Network there is no fixed topology. The topology is changeable. The nodes move with variety of velocity in various directions. Vehicular Adhoc networks are clustered into non-overlapping sub networks, each local to a geographic area referred to as a cell. Each cell has a server that maintains a list of pseudonyms valid for use in the cell. The source node and destination node are configured and identify whether the destination node is within the coverage area of source node by sending request packets to the destination node. If the destination node is not within in the coverage area, the source nodes transmit packets through the intermediate nodes. The routing path is calculated based on the Hybrid Location based Adhoc (HLAR) routing mechanism. It efficiently make use of all the location information available, to minimize the routing overhead, and to gracefully exit to reactive routing as the location information degrades.