Rising Issues in VANET Communication and Security : A State of Art Survey

VANET (Vehicular Adhoc Network) has made an evolution in the transportation hi-tech system in most of the developed countries. VANET plays an important role in an intelligent transportation system (ITS). This paper gives an overall survey on the research in VANET security and communication. It also gives parameters considered by the previous researchers. After the survey, it considered the authentication and message forwarding issues required more research. Authentication is first line of security in VANET; it avoids attacks made by the malicious nodes. Previous research has come up with some Cryptographic, Trust based, Id based, and Group signature based authentication schemes. Speed of authentication and privacy preservation are the important parameters in VANET authentication. This paper presented the AECC (Adaptive Elliptic Curve Cryptography), and EECC (Enhanced Elliptic Curve Cryptography) schemes to improve the speed and security of authentication. In AECC, the key size is adaptive, i.e. different sizes of keys are generated during the key generation phase. Three ranges are specified for key sizes: small, large, and medium. In EECC, added an extra parameter during the transmission of information from, the vehicle to the RSU for key generation. This additional parameter gives the information about the vehicle ID, and the location of the vehicle to the RSU and the other vehicle. Under the communication issue of VANET, the paper gives priority based message forwarding for improving the message forwarding scheme. It handles emergency situations more effectively. Keywords—Vehicular Adhoc Network (VANET); Adaptive Elliptic Curve Cryptography (AECC); Enhanced Elliptic Curve Cryptography (EECC); authentication; message forwarding


I. INTRODUCTION
The VANET becomes a milestone in an intelligent transportation system.It helps to automate the traffic monitoring system more efficiently.In VANETs nodes, there is nothing, but vehicles and the RSU (Road Side Unit), which communicate with each other.RSU's are deployed on the roads, and help to maintain the communication when the vehicles are not in the coverage of each other.There are different issues in VANET.Due to an open medium of VANET, the outside nodes can easily, access the network.Security is a major challenge in VANET.Malicious nodes can carry different attacks to misguide the driver.Communication is the heart of all networks; in VANET, the nodes are moving fast so, there is the need of a faster and smart communication mechanism, to handle emergency situations [11].In this paper, Section 1 gives an introduction of VANET, communication.Section 2 gives a detailed literature survey of the authentication and communication issues in VANET.Section 3 gives an analysis about the research parameter considered by the previous researchers, and the area for new research.Section 4 gives the objectives and solutions for the same.

A. VANET Architecture
The VANET architecture is shown in Fig. 1.It shows the scenario of the vehicular adhoc network, and the different ways of communication in VANET.There are three ways of communication, namely, V2V (Vehicle to Vehicle), V2I (Vehicle to Infrastructure), and I2V (Infrastructure to Vehicle) [1].

B. Communication in VANET
Wireless Access in Vehicular Environment 1) (WAVE): Lots of efforts have been made to design the new standards for the services and the interfaces for VANET.These standards form the basis for a wide range of applications in the vehicular network environments.A set of standardized services and interfaces defined under WAVE is shown in Fig. 2.These services and interfaces cooperatively enable a secure V2V and V2R communications in a rapidly changing communications environment where communications and transactions need to be completed in a short time frame.www.ijacsa.thesai.org The WAVE architecture is developed, based on the IEEE 802.11p and the IEEE P1609 standards (Nadeem, 2004).The IEEE 802.11p deals with the physical and Media Access Control layers, whereas the IEEE 1609 deals with the higherlayer protocols [3].

WAVE Architecture:
2) The IEEE 1609 family of standards for WAVE: The IEEE has defined four standards, and released them for trial use (IEEE, 2007).Fig. 2 shows the architecture of the WAVE family, of standards.These standards can be defined as follows [3]:  This standard defines the routing and transport layer services.It also defines a WAVE-specific message alternative to IPv6 that can be supported by the applications.This standard also defines, the Management Information Base (MIB) for the protocol stack.IEEE 1609.4 (Multi-Channel Operations): Multi-Channel Operations: This standard defines, the specifications of the multi-channel in the DSRC.This is an enhancement to the IEEE 802.11aMedia Access Control (MAC) standard.

II. LITERATURE SURVEY ON AUTHENTICATION & COMMUNICATION IN VANET
VANET can be affected by many attacks like denial of service, message suppression, and the propagation of false message attacks etc.In order to increase safety, in data transmission, security, is the most important challenge in VANET [2], [17].The Literature survey shows some requirement to achieve security, Leinmuller Schoch et al.Table 1 shows the detailed survey of the research in VANET along with its strength, weakness, and future scope of the research.For survey purpose paper from communication and security in VANET are considered.Studied papers are from 2004 to 2016.
Table 2 shows the parameters considered by a previous researcher.After study of each paper, which parameters are consider by researcher is identified.Using identified parameters value, pie chart is drawn.Fig. 3    Fig. 3 shows that there is a need of more research in secure message forwarding, emergency event handling and packet delivery ratio.Secure message forwarding and efficient event handling can be the objectives of future work.Considering this need priority based message forwarding for emergency event handling is the objective set for research.Secondly, as VANET, is a dynamic network, density and speed of the vehicle is another issue to increase the overhead.As authentication is the start of any secure communication if speed of authentication is improving, it can help to give time for RSU to serve more number of vehicles.The Packet delivery ratio can improve by attack detection and improving speed while communication.Considering this need faster and secure authentication objective is set for research.

A. Objectives:
To provide faster authentication in VANET.

1)
To provide a secure and priority based message 2) forwarding system.4 shows framework which is designed for research work.It gives direction for research to achieve set objectives.As per framework first task is setting topology of VANET for experimentation; secondly, authentication of vehicle.In authentication first task is to implement basic ECC algorithm for authentication then variation in ECC by AECC and EECC algorithms is achieved.Third task gives malicious node detection while authentication and last task will be priority based message forwarding.Detailed description of each framework blocks is given below.

A. Topology
It shows the front end of the project where the vehicle scenario is created using VSIM (VANET Simulator) tools.VSIM is used for objective implementation and testing.VSIM is a java based simulator, which provides different classes to create an environment for VANET.Protocols and ideas can implement in a simulator using JAVA.Different maps are available to test protocols; the map can upload in the simulator.Different road scenarios are available for each map; we can upload those scenarios in a simulator after uploading the map.The simulator has different input parameters like number of vehicles, time stamp of each vehicle, road traffic density, event priority, time slot, etc. that can provide to the simulator.

B. Authentication
The authentication scheme is implemented in three different ways-ECC based authentication, Adaptive ECC based authentication, and Enhanced ECC based authentication.Table 3 shows the terms used for Adaptive ECC, and the Enhanced ECC algorithm for authentication.ECC Based Authentication: authentication using a) elliptic curve cryptography.
Elliptic curve cryptographic algorithm: 1) Elliptic Curve Cryptography (ECC) was discovered in 1985 by Victor Miller (IBM) and Neil Koblitz (University of Washington) as an alternative mechanism for implementing public-key cryptography.Few terms that will be used, E -> Elliptic Curve P -> Point on the curve n -> Maximum limit ( This should be a prime number )

Key generation 2)
Key generation is an important part where need to generate both public key and private key.The sender will be encrypting the message with receiver's public key and the receiver will decrypt its private key.Now, number ‗d' selected within the range of ‗n'.Using the following equation Public key will be generated.

Q = d * P
Where, d = the random number that have been selected within the range of (1 to n-1).P = the point on the curve.‗Q' is the public key and ‗d' is the private key.www.ijacsa.thesai.orgEncryption 3) Let ‗m' be the message that we are sending.We have to represent this message on the curve.This has in-depth implementation details.All the advance research on ECC is done by a company called certicom.
Let it be C1 and C2.C1 = k*P C2 = M + k*Q C1 and C2 will be sent.

4)
We have to get back the message ‗m' that was send to us.

M = C2d * C1
M is the original message that we have send.

AECC (Adaptive Elliptic Curve Cryptography) based b) authentication:
The ECC algorithm for authentication in VANET, can fail, if the user side password is cracked by an attacker using a permutation and combination of alphabets.So, the password is a main flaw in this.This problem can be overcome by, either adding some parameter along with the password for key generation, or using an adaptive key size algorithm.This algorithm uses the random key size where no attacker can guess, the key size at the current time, and tries to break it.This system uses a cooperative system to decide the key size after every defined timeslot.When an attacker tries to guess the key to break the system as the ECC is strong enough this does not happen easily.But when an attacker succeeds to do so, because of the adaptive key size (AKS) algorithm, the key is no longer relevant to that attacker.Attack detection: Using node location and time stamp 3) information Sybil and replica attack detection will be achieve.

D. Priority based Message Forwarding
In VANET, different types of messages are useddepending on the type of information in the messages, e.g.Safety messages like tunnel ahead, speed limit, 1) diversion, speed breaker, etc. [13].
User comfort messages, like navigation info, social 3) networking info, video/audio data, etc.

IEEE 1609. 1 (
Resource Manager): This standard defines the services, and the interfaces of the WAVE Resource Manager applications.It describes the message formats and the response to those messages.It also describes the data storage format that is used by the applications to access other architecture.IEEE 1609.2 (Security Services): This standard defines security and secure message formatting, and processing.It also, defines how secure messages are exchanged.
(2007), timely delivery, location accuracy, correctness of message privacy and liability, as security requirements.Razzaque M. et al. (2013) stated that the security model in VANET should satisfy the authentication, verification of data consistency, message integrity, availability, non-repudiation, privacy and traceability, revocation and real-time constraints as a security requirement [16].Ahmad Yusri Dak et al. non-repudiation are security requirements.
Fig. 3. Previous research work on different parameters.

Fig. 5
Fig.5shows simple Elliptic Curve which considered for ECC algorithm.

TABLE I .
SURVEY ON SECURITY AND COMMUNICATION IN VANET 1.If CA, RA, or RSU compromise, the scheme can fail.1. Authentication process speed can improve.2. Trust value of CA, RA and RSU can be used to find a compromise node. 1.The computation effort is much lower than the other methods in hash function 2. VASS has the properties of security such 1.Vehicle to infrastructure communication not considered.1. Vehicle to Infrastructure authentication can be provided.www.ijacsa.thesai.orgas privacy, authentication, and Sybil attack.

TABLE III .
TERMS USED FOR ALGORITHM

Algorithm / Pseudo code for AECC based authentication:
In the Enhanced ECC algorithm, we added an extra parameter during the transmission of information from the vehicle to the RSU for key generation.This additional parameter gives the information about the vehicle ID, and the location of the vehicle to the RSU, and the other vehicle.This additional parameter is also used in key generation.This algorithm provides replica and Sybil attack detection along with authentication.Algorithm for tracking the 1) location of vehicles from which a message is received or which it is trying to communicate.Time based algorithm: Assigning time stamp to the 2) message.