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CHAPTER 2

LITERATURE REVIEW

2.1 INTRODUCTION

This chapter discusses in detail about the settings involved in

vehicular ad-hoc network with numerous works concentrated by different

authors. A Vehicular Ad-Hoc Network (VANET) is a technology that has

attracted several industries. Security parameters in VANET are now receiving

popularity in the research community. In VANET environment, significant

decision format has to be determined with the problems related to attack

modeling, optimizing response and allotment of defense resources in a wide

manner. However, a single defense mechanism cannot provide solution to the

attack models that are affecting the VANETs. The game theory model is used

as a defense mechanism against sophisticated and complex type of attacks

arising in VANET. With game-theoretic framework, suspicious procedures are

optimized based on the optimal exploitation of traffic organizes and security

framework is investigated both in the urban and rural scenarios regarding

threats posed by malicious nodes.

The security applications help to keep lives move smoothly and

recover traffic conditions during problematic cases. VANET plays a major

role in networks due to their application of ad hoc network technology.

Vehicles are the best part of those networks and their capability is to be

efficiently handled in self organizing networks with no previous knowledge

about the nodes in the network. Their safety altitude is very low and they are

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highly susceptible components of the network which can be targeted easily.

Hence to provide security in any of the existing methods can also be used by

solving the drawbacks mentioned or noticed in them and the following section

describes the existing methods.

2.2 HEURISTIC-BASED ANT COLONY OPTIMIZATION TO

ENHANCE SECURITY IN VANETs

Security is always denoted with price regarding performance

degradation and it should be determined carefully. Wireless ad hoc networks

(WANETs) normally offer communication among the shared wireless

channel, by not considering or not employing any preceding infrastructure.

Creation of end-to-end secure paths in such WANETs is more demanding

because of lack of central authorities. Its impact on network performance is

not noticed. Chi Zhang et al (2011), depending on common random network

model, the asymptotic behaviors of secure throughput and delay with the

common transmission range are determined. The possibility of neighboring

nodes having a primary security association is also determined when the

network size is adequately large. Normally security has a cost: because all the

communications normally function on secure links and hence there is

deprivation in the network performance. Even when the throughput is zero,

because of the network size is randomly large; there is still a possibility to

form throughput-order-optimal secure WANETs. Thus another author

suggests a different way to provide security.

In wireless networks, wandering of mobile users is high and

authentication to be provided to them is difficult. Daojing He et al (2011)

designed a privacy-preserving universal authentication protocol, named

Priauth. It provides authentication for eavesdroppers and foreign servers;

authentication efficiency is high when session keys are authorized. The

attacker has control against overall communication channels (among user,

27

foreign server, home server), i.e., attacker can intercept, insert, delete, or

modify any message running through the channel. Four types of threats are

normally present in user authentication namely; message en route threat, false

mobile user threat, DoS attack and deposit-case attack. In Priauth, a roaming

user, a foreign server and a home server is engaged to present a demo in order

to contribute authentication. In Priauth, a session key is presented to the

roaming user by the foreign server, in prior to the authentication of roaming

user. In Priauth foreign servers can be verified based on the revocation list

(RL) i.e., whether the roaming user moved from the home server is revoked or

not.

Normally all nodes in the network introduces two forms of traffic,

namely private and open, at rates selected in order to exploit a global utility

function which are subjected to network stability and secrecy constraints. The

secrecy limitation imposes a randomly low mutual information leakage from

the source to all nodes in the network, excluding the sink node. C. Emre

Koksal et al (2013) presented a method to find the obtainable rate regions for

the problem of single and multi-user systems that are to be attained by

considering the nodes having full Channel State Information (CSI) of their

neighbors. A combined flow control namely, scheduling and private encoding

method is also provided. The downside is that no results are found for partial

CSI that are available at each node hence necessary steps are to be taken.

More security problems are handled by wireless networks and the successive

part explains about the security issues in mobile ad hoc networks.

Secure communication in Mobile Ad hoc Networks (MANETs) can

be obtained based on the applications that are running in the networks and

they must be synchronized by correct communication policies. Policy

enforcement in MANETs is a great issue because they are in need of the

infrastructure and believed that entities meet in traditional distributed systems.

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Hence, Gang Xu et al (2011) presented a plan and execution of a policy

enforcing mechanism is done using Satem, a kernel-level trusted execution

monitor was formed based on Trusted Platform Module. Two different

applications running on diverse nodes may involve in communication only if

those nodes implement the same set of policies for the application and the

fundamental protocols used by the application. Nodes are able to model

trusted application-centric networks by following the above mentioned way.

In accordance to allowing a node to mingle in such a network, Satem checks

for its honesty of enforcing the required set of policies. Satem safeguards the

policies and the software enforces the policies from being damaged. If any of

the policies are compromised, then Satem detaches the node from the

network. Authentication can be provided to user specifically, so there will be

minimized security problems.

High securities MANETs are to be secured and for that a

prevention-based method called continuous user authentication are employed.

Intrusion detection systems (IDSs) are also vital in MANETs to successfully

detect mischievous activities. The optimal method can be gained by

combining continuous user authentication and IDSs in a distributed manner,

but the difficulty caused is denoted as a Partially Observable Markov

Decision Process (POMDP) multi-armed bandit problem. So, Shengrong Bu

et al (2011) proposed a structural result method to crack the problem for a

large network with a variety of nodes. The policies resulting from structural

outcomes are simple to execute in practical MANETs. The system

performance from the structural results method is equal to the value iteration

algorithm which is calculated on the basis of lower computational complexity.

More node states such as mobility and wireless channels are to be considered

in making the scheduling decisions in MANETs and it has not happened in the

proposed method.

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Thus methods used in MANETs to provide security are more

refreshing and the security problem is also faced by Vehicular Ad hoc

Networks (VANETs), hence necessary steps are needed to be taken to provide

full security. Vehicular communication networking is mostly important to aid

road safety, to handle traffic and infotainment propagation for drivers and

passengers. Xiaodong Lin et al (2008) made a review on the current

standardization process that denotes the approaches which offer security

services and safeguard driver privacy for Wireless Access in Vehicular

Environments (WAVE) applications. Two primary problems namely,

certificate revocation and conditional privacy preservation are addressed by

the author to make the standards practical. Protected certificate revocation and

provisional privacy preservation can be obtained by employing a group of

new security methods as well as by using a Public Key Infrastructure (PKI).

Congestion control problems may also lack in providing security in VANET.

The cooperative vehicular ad-hoc networks needs the design of

efficient congestion control policies that assure for stable and reliable

communications among vehicles and infrastructure nodes. The policy must

decrease the load on the communications channel, while fulfilling the strict

application’s reliability requirements. Hence, Miguel Sepulcre et al (2011)

designed and estimated a contextual cooperative congestion control policy

that utilizes the traffic context information of each vehicle to decrease the

channel load, while satisfying the vehicular applications requirements. Three

different operational modes are examined with increasing cooperation and

usage of traffic context information. They are: autonomous mode (AM),

cooperative mode (CM), and contextual cooperative modes (CCM). A

framework is to be designed to extend the policy to multi-application

scenarios via the development of a new communication adaptation layer.

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Dusit Niyato et al (2011) examined the difficulty of accessing an

optimal channel, basically to offer quality of service (QoS) for data

transmission in cognitive vehicular networks. In such networks, the vehicular

nodes are able to opportunistically access the radio channels named as shared-

use channels, which are allotted to licensed users. They are also able to keep a

channel for dedicated access named as exclusive-use channel for data

transmission. A structure for channel access management is designed for

cluster-based communication within vehicular nodes. The structure contains

three factors namely: for shared-use channels an opportunistic access, an

exclusive-use channel reserved, for cluster size control. A hierarchical

optimization model is also designed for the framework to attain the optimal

policy. The hierarchical optimization method includes two constrained

Markov decision process (CMDP) formulations for the above mentioned

factors.

Location privacy is also to be considered to offer authentication.

The privacy quality among vehicular ad hoc networks (VANETs) is based on

location privacy which is crucial for VANETs to flourish completely. Frequent

pseudonym changing presents a capable solution for location privacy in

VANETs, if changes are made to the pseudonyms in an improper time or

location, the solution may become invalid. Hence, Rongxing Lu et al (2012),

to overcome the problem, proposed a valuable pseudonym changing at social

spots (PCS) strategy to attain the provable location privacy. The social spot

where numerous vehicles may meet was introduced first of all, e.g., a road

junction when the traffic light turns red or a open parking lot near a shopping

mall. The anonymity set size is considered as the location privacy metric and

two anonymity set analytic models are developed to significantly examine the

location privacy that is obtained by the PCS strategy. The current model

tracks a vehicle in a spatial–temporal way; hence advanced technique is to be

considered which should use more character factors to track a vehicle and to

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discover new location-privacy-enhanced techniques under such a stronger

threat model. Still an enhanced method is needed to provide safety for

vehicular communication.

IEEE and ASTM accepted the dedicated short-range communication

(DSRC) standard which is the primary method for the next generation of

vehicular safety communications. Communication services based vehicle

safety normally needs dependable and quick message delivery which

generally appeals broadcast communications in vehicular ad hoc networks

(VANETs). Xiaomin Ma et al (2012) designed and approved a distributive

cross-layer method for the plan of the control channel in DSRC and three

levels of broadcast services are involved that are serious to most possible

vehicle-safety-related applications. The network parameters based on current

traffic load and network conditions are to be identified using IEEE 802.11p

for better performance and reliability, because that is not processed by the

proposed method. Signature based privacy is to be provided for VANETs.

Kyung-Ah Shim (2012) designed a Conditional Privacy-Preserving

Authentication Scheme (CPAS), with the help of pseudo identity based

signatures to provide a safe vehicle-to-infrastructure (V2I) communications in

VANETs. Each message sent by a vehicle is mapped to a distinct pseudo-

identity, and a trust authority can constantly regain the actual identity of a

vehicle from any pseudo-identity which is the functionality of CPAS. A

roadside unit (RSU) is employed to validate multiple collected signatures and

2540 signed-messages, thus significantly minimizing the total verification

time. The pseudo- identity (ID)-based signature (IBS) method is proposed for

capable batch verification which is more appropriate for the vehicle-to-

infrastructure (V2I) communications than the vehicle-to-vehicle (V2V)

communications. The estimation of CPAS on a large-scale VANET testbed

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with changing vehicle mobility models are to be performed which are not

considered in CPAS.

Jaehoon (Paul) Jeong et al (2012) presented a Trajectory-based

Statistical Forwarding (TSF) method, customized for the multihop data

delivery from infrastructure nodes (e.g., Internet access points) to moving

vehicles in VANET. The author made the first attempt to examine the way to

forcefully exploit the packet destination vehicle’s trajectory for that type of

infrastructure-to-vehicle data delivery. The data delivery is achieved through

the computation of a target point based on the destination. Vehicle’s trajectory

is a best meeting point of the packet and the destination vehicle. Packets are

forwarded up in multihop to a chosen target point by TSF, where, the vehicle

is about to pass. These forms of target points are chosen optimally to reduce

the packet delivery delay while fulfilling the necessary packet delivery

probability. The trajectories of vehicles are to be utilized completely which

are used as packet forwarders or carriers for the more capable data forwarding

in vehicular networks.

Francisco Javier Ros et al (2012) designed a broadcast algorithm

which is appropriate for a numerous vehicular situations and it utilizes only

the local information obtained through a periodic beacon messages, enclosing

affirmation of the circulated broadcast messages. The vehicle may or may not

belong to a connected dominating set (CDS). Hence a decision is to be made

by the vehicle. A shorter waiting period is offered to the vehicles in the CDS

in prior to the achievable retransmission. At time-out termination,

retransmission by the vehicle is possible only if it is alert about at least one

neighbor in need of the message. Intermittent connectivity and form of new

neighbors are located by reestablishing the evaluation timer. Investigation is

in progress in order to further minimize the protocol overhead during the

presence of multiple simultaneous broadcasting tasks. The protocol must be

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suitable for delay-critical safety application. Hence usage of retransmission

time-out is to be investigated which has given a delay constraint from the

applications.

Traffic monitoring with examination vehicles along with GPS

receivers promises important improvements in cost, coverage, and accuracy

over devoted infrastructure systems. Privacy concern problems are more in

existing systems. Baik Hoh et al (2011) depicted a system based on virtual trip

lines and an associated cloaking method. Another system design is also made

in which the privacy requirements are relaxed to increase the accuracy of real-

time traffic evaluation. Virtual trip lines are represented as geographic

markers that denotes where vehicles are allowed to contribute speed updates.

These markers are used to avoid exact privacy sensitive locations. The system

is demonstrated with GPS smartphone clients and performs a controlled

research with more phone-equipped drivers rotating a highway segment. Key

based secrecy can also be provided for VANETs.

Vehicular Ad Hoc Networks (VANETs) involves the Public Key

Infrastructure (PKI) and Certificate Revocation Lists (CRLs) to provide

security for them. In PKI system, the verification of a received message is

achieved by examining whether the certificate of the sender is integrated in

the current CRL, and confirming the authenticity of the certificate and

signature of the sender. Albert Wasef et al (2010) designed an Expedite

Message Authentication Protocol (EMAP) for VANETs that alters the time-

consuming CRL checking method with capable revocation checking method.

The revocation checking method in EMAP utilizes a keyed Hash Message

Authentication Code (HMAC), where the key involved in evaluating the

HMAC is common among non-revoked On-Board Units (OBUs). EMAP also

involves in new probabilistic key distribution, which facilitates non-revoked

OBUs to firmly share and revise a secret key.

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Numerous security architectures are designed for Vehicular

Communication (VC) systems, with an agreement of using public key

cryptography for secure communications. But none of them has been

examined and mentioned the problem of Certificate Revocation List (CRL)

distribution. P. P. Papadimitratos et al (2008) proposed a design that is

scalable and efficient to deliver flawlessly CRLs to all nodes within a region.

The source for the design of such CRL distribution systems is placed,

displaying how to configure them to attain more stringent requirements. The

difficulty of CRL distribution in VC systems is examined. The way in which

the CRL transmissions occur with very low bandwidth is considered and all

vehicles can gain the latest CRL within a delay of minimum minutes of drive,

e.g., the duration of a travel. The trade-offs are displayed and the way the

system is to be configured to minimize the delivery delay is also investigated.

Certification concept along with key authority can also be employed.

The certificate authority provides keys and certificates to vehicles

for safety in VANET. Each vehicle assigns these certificates to other VANET

members and then signs messages against these certificates. If the certificate

authority wants to cancel a certificate (e.g. due to a break in trust), it generally

distributes a certificate revocation list (CRL). Kenneth Laberteaux et al

(2008) designed a system for car-to-car epidemic distribution of certificate

revocation lists that is normally rapid and resourceful. Large-scale emulations

based on sensible mobility traces that the epidemic model considerably

outperforms methods that only utilize road side unit distribution points. The

vehicles are used to spread CRL updates in an epidemic manner. Only the

necessary CRL update sections can be communicated, there by reducing the

communication bandwidth usage.

Jason Haas et al (2009) designed a lightweight device for revoking

security certificates that are suitable for the limited bandwidth and hardware

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cost constraints of a VANET. The author proposed the mechanisms that attain

the goals of minimized CRL size, a computationally resourceful mechanism

for resolving if a certificate is on the CRL, and a lightweight mechanism for

exchanging CRL updates. A proper verification of the security of the

mechanism is also presented for minimizing the size of CRLs. Two

contributions are employed by the author, first, a certificate organization

scheme is proposed where certificates for a single vehicle are connected by a

single, secret revocation key. Without the key, certificates are tedious to

group, by which the privacy of a vehicle is preserved. Analysis is also made

on the certificates and enhanced the practicality of distributing CRLs. A

method for passing CRL updates is proposed, rather than the complete CRL,

which minimizes the forced network overhead and is analogous to delta

CRLs.

Albert Wasef et al (2010) designed a capable Distributed Certificate

Service (DCS) method for vehicular networks. For certificate service among

varied administrative authorities, a flexible interoperability is provided by the

designed method. A capable way for any On-Board Units (OBUs) to revise its

certificate from the present infrastructure Road-Side Units (RSUs) in an

appropriate manner is also proposed. The DCS scheme proposes an aggregate

batch verification method for authenticating certificate-based signatures,

which considerably minimizes the verification overhead. Security

examination and performance assessment reveals that the DCS scheme can

minimize the complexity of certificate management, and realizes brilliant

security and effectiveness for vehicular communications. The only drawback

is that the revocation problem under the context of the DCS scheme is to be

considered and solved.

Security is important for the dependable operation of vehicular ad

hoc networks (VANETs). The most serious security problem is the revocation

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of misbehaving vehicles, which is necessary for the avoidance of malicious

vehicles from risking the safety of other vehicles. So Nang-Wen Wang et al.

(2009) designed an efficient decentralized revocation (EDR) procedure

depending on a new pairing-based threshold method and a probabilistic key

distribution technique. The EDR protocol develops the safety levels in

VANETs as it reduces the revocation susceptibility window presented in

conventional certificate revocation lists (CRLs). The downside is that focus is

to be made on categorizing the received messages in accordance to their

correctness degree and activate the revocation process for a misbehaving

vehicle which will transmit malicious messages.

Some malicious attacks may result in lack of security, especially the

Denial of service attacks are more problematic and hence necessary steps are

to be taken to avoid them. Many researches have accomplished for message

authentication in wireless networks; especially VANETs handle different

objection, such as real-time constraints, processing restrictions, memory

restraint, etc. Analysis is made on the requirements for feasible VANET

authentication. Ahren Studer et al (2008) designed a customized version of

Timed Efficient Stream Loss-tolerant Authentication (TESLA) and

TESLA++. TESLA and TESLA++ offer the same computationally capable

broadcast authentication and TESLA with minimized memory requirements.

A new hybrid authentication mechanism is designed in order to mention the

scope of needs among VANET and the new mechanism is VANET

Authentication using Signatures and TESLA++ (VAST). VAST joins the

advantages of Elliptic Curve Digital Signature Algorithm (ECDSA) and

TESLA++.

Grossklags et al (2008) analyzed security issues of VANET and

observed the user behavior of weak security link. Mostly allowed attack in

VANET is distributed. Distributed denial-of-service (DDoS) and spam

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distribution also continue to be unabated. Examination is made based on the

way the motivations move between investment in protection and insurance,

and subjects to factors such as network size, type of attack, loss probability,

loss magnitude, and cost of technology. Nash equilibrium is also characterized

and social optimality for diverse classes of attacks and defenses are presented.

In the weakest-target game for all parameter contexts, more attempts are made

at Nash equilibrium rather than at the social optimum. A security game is

defined as a game-theoretic model that confines necessary characteristics of

decision making to protect and self-insure resources within a network.

Centrality based security can also be provided to VANETs. Jens

Grossklags et al (2008) concentrated on the traffic dynamics than the static

road system and involved the centrality metrics of the traffic in each elements

of the map. The consideration of individual security decision-making is to be

enhanced by merging formal and behavioral analysis. For security decision-

making, a game-theoretic model is identified that simplify the “weakest link”

game, and an experiment is conducted to expose dissimilarities among

predicted and observed user behavior. The author explored the relationship

among economic and psychological-behavioral considerations for enhanced

or declined system security. The focal point is made on a weakest-link

security scheme and convergence to Nash equilibrium was not able to be

attained within a limited period of time. The data collected still now in the

work didn’t notice convergence to any of the expected equilibrium at all.

Betweenness centrality depending on shortest paths is a normal

measure of control employed in many studies and executed in all applicable

software tools for network analysis. Ulrik Brandes (2008) presented a paper in

which a number of variants to be analyzed are placed into context and it

predicts to be assessable with simple variants of the algorithm normally used

for the standard case. Several variants of betweenness centrality is discussed,

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in which either the interest is moved (e.g., to edges), or the range of

applicability is elongated (e.g., to valued networks). Unlike associated

measures such as network-flow betweenness, current-flow betweenness, or

load, these do not modify the underlying model of transportation along

geodesic trajectories. For the variants, small alteration of the normally used

algorithm for the normal case resulted in algorithms with the same asymptotic

time complexity (except for length-valued edges), and with similar structure

of computation.

Thus with centrality concept a new security game has been proposed

to provide complete security for VANET. Tansu Alpcan & Sonja Buchegger

(2011) designed a security game for vehicular network to avoid attacks. The

security games involve zero sum game and fuzzy game by computing

centrality measures. Using traffic engineering systems, the game theoretic

method is designed. Markov Chains (MC) for designing the game model in

the quantitative assessment is also presented. The security games designed for

vehicular networks uses centrality measures that are figured out by mapping

the car networks centrality values to the fundamental road topology. The

vehicular network model has three levels: data traffic, vehicular traffic, and

road network. Data and vehicular traffic are dynamic while road network is

naturally fixed.

In Vehicular Ad Hoc Networks (VANETs), there are no end-to-end

connections and nodes taking that as the advantage to forward messages, to

make messaging possible. Thus it is vital to make sure that nodes have

motivations to forward messages for others, regardless of that the routing

protocols in VANETs are diverse from traditional end-to-end routing

protocols. Tingting Chen et al (2010) made a study in a way to activate

message forwarding in VANETs and the approach depends on coalitional

game theory. The incentive method is to control the storage space required in

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containing details of each node. Depending on the testbed an incentive

method is designed for message broadcasting in vehicular communication.

Initially the architecture of the incentive method is presented. A payoff

allocation technology is introduced which is utilized in the incentive method.

Later an overall architecture of incentive method is presented depending on

the payoff allocation. Finally, the incentive method is formed using payoff

allocation that solves the cheating i.e., inter-vehicle communication of

incentive method with errors.

Ghassan Samara et al (2010) presented a vehicular network with

secured communication and provide preservation against the adversary which

is denoted as attacker interruption. The secured VANET provides a

satisfactory level in broadcasting messages by comforting the level of drivers

and manufactures for a smooth and safe life. The strength of VANET is

required to provide security and privacy characters. An analysis on the

different forms of security complications and challenges of VANET are made.

Also a solution is provided to the security problems and challenges based on

the analysis. The solution provided for VANET security ensures the message

received is valid. A huge analysis for the VANET security challenges is made.

Limitation for the analysis is carried out along with the simulation test to

maintain a secure VANET network.

2.3 ENHANCED GAME THEORY APPROACH USING NASH

EQUILIBRIUM INTEGRATED WITH MARKOV CHAINS

FOR VANET SECURITY

Up to date network programming protocols contributed a significant

way to modernize program images that are functioning on sensor nodes

without admitting physical access to them. Securing the updates is the major

problem, because of the open environment in which the sensor nodes are

always set up. Many methods are presented to solve the issues, but when

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cryptographically energetic protocols are used; their computational costs

(power consumption and communication costs) become comparably high. So,

Hailun Tan et al (2011) designed a new cost-effective security method mainly

for network programming. A protocol called multihop network programming

has to be secured and for that the designed method was employed by

considering the multiple one-way hash chains. The method reduces the

computational cost, minimizes power consumption and also holds less

communication costs by protecting multihop propagation of a program

images. Performance evaluation of the method is also presented, which is

executed in TinyOS regarding latency and energy consumption. Steps are to

be taken to provide security using the presented scheme in hierarchical

topologies for enhanced scalability and especially for DoS attack.

Thus, an opponent can capture and compromise sensor nodes to

form replicas of them and then increase the attacks with these replicas and

these all happens because of the neglected nature of wireless sensor networks.

These replica node attacks are critical because they permit the attacker to

leverage the concession of few nodes to apply control over the network.

Several replica node detection schemes are proposed earlier and those

schemes rely on fixed sensor locations and hence not worthy for mobile

sensor networks (sensors are normally in motion). Jun-Won Ho et al (2011)

designed a fast and efficient mobile replica node detection method along with

the usage of Sequential Probability Ratio Test. The communication between

the detector and the opponent is modeled as a repeated game and Nash

equilibrium was also found. The Nash equilibrium represents that even the

attacker’s best gains are still limited due to the grouping of detection and

quarantine. The proposed method rapidly detects mobile replicas only when

small numbers of location claims are present and is not applicable for large

number of location claims. So, necessary steps have to be taken to solve it.

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Congestion control has also to be considered because they may also inject

attacks.

The event-driven environment of wireless sensor networks (WSNs)

points to erratic network load. Accordingly, congestion happens at sensors

which receive more data than usually forwarded those results in wastage of

energy, reduction in throughput and loss of packets. Xiaoyan Yin et al (2009)

designed a rate-based fairness-aware congestion control (FACC) protocol is

presented on the basis of performance rate, which controls congestion and

gains almost fair bandwidth allocation for diverse flows. In FACC, central

relaying sensor nodes are classified as near-source and near-sink nodes. Near-

source nodes preserve a per-flow state which is controlled by it and almost

fair rate to all passing flow is allotted. Regarding packet loss, FACC becomes

constant over a particular time period during the increase in allowed traffic

load. No congestion control concludes in rising packet loss as the allowed

traffic load increases or as time elapses. There are chances for intrusion of

attacks and it is mostly affected by Ad hoc low power wireless network.

Security has to be provided in ad hoc low power wireless networks

basically for denial of communication at the routing levels. Eugene

Vasserman et al (2013) made an analysis on resource reduction attacks at the

routing protocol layer that forever damage networks by rapidly exhausting

nodes’ battery power. The “Vampire” attack does not rely on any special

protocol, but they mostly depend on the property of various classes of routing

protocols. The reviewed protocols are vulnerable to Vampire attacks that are

mostly destructive and hard to detect. Increase in the network-wide energy

usage by a single Vampire occurs at the worst case. Also fully acceptable

solution for Vampire attacks in the topology discovery phase is not found.

Similarly, the mobile network is also to be considered.

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In addition to vampire attacks, in wireless sensor networks (WSNs)

the most vulnerable attacks are compromised node and denial of service.

Tao Shu et al (2010) made a review on data delivery methods, which avoids

the black hole creation by these attacks. Classic multipath routing schemes are

also susceptible to such attacks because of their deterministic nature. In the

proposed designs the routes are collected by the “shares” of diverse packet

changes in accordance with the time. Hence, when the opponents find the

routing algorithm, they cannot identify the routes that are employed for

transmitting each packet. An optimization technique is used to decrease the

end-to-end energy consumption with provided security constraints. The black

holes block every path of the source and the sink. The cut around sink attack

does not allow any secret share from the source even when disturbed by the

adversary. Hence steps to be taken to address these attacks.

Attacks are not only applicable in WSN but also plays major role in

MANETs basically while routing. Mike Burmester & Breno de Medeiros

(2009) mentioned that the protection verification of the route discovery

algorithm is very effective. The algorithm is susceptible to a hidden channel

attack and investigations are made for the security framework that was used

for route discovery. There are excess of additional hidden channels that are

available through concurrent implementation of route discovery protocols. In

addition to the background of mobility, route discovery take place

concurrently with data communication. Huge additional bandwidth is

obviously caused and available to adversarial nodes. Consequently,

adversarial nodes will partition the routes by inserting non-existing links in

the work, which is unfeasible to avoid. To tackle the shortcoming, either

additional flexible definitions of routes must be engaged (e.g., redundant

routing) or it is necessary to tackle global threats directly, and more

commonly man-in-the-middle attacks.

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An enhanced way to provide secure routing is to be considered and

hence different ways are adapted in MANET. In ad hoc network privacy-

preserving routing is wanted which has stable privacy protection. Data

packets and control packets are linkable and distinguishable in the proposed

method and none of the old methods show complete unlinkability or

unobservability property. Hence, Zhiguo Wan et al (2012) presented

Unobservable Secure On-Demand Routing (USOR) protocol which

contributes absolute unlinkability or unobservability property. USOR is well-

organized and consolidates group signature and ID-based encryption for route

discovery. The protocol runs on NS2 and reviews the performance of USOR,

which displays that USOR has acceptable performance regarding the packet

delivery ratio, latency and normalized control bytes. But the downside is that

USOR is still affected by wormhole attacks, black hole attacks and DoS

attacks which is a challenging task, needs in-depth investigation.

A malicious node forms a black hole attack on MANET. It finds the

route from a source to a destination and modifies sequence number and hop

count of the routing message. Ming-Yang Su (2011) designed IDS (intrusion

detection system) nodes that are employed in MANETs in order to detect and

avoid black hole attacks. The IDS nodes are set to sniff node to perform ABM

(Anti-Blackhole Mechanism) function. ABM is used to find a suspicious

value of a node regarding the difference among the routing messages which

are routed from the node. Ad hoc On-Demand Distance Vector (AODV)

provides a network connection when the number of IDS cannot cover most of

the area, because of less processing loads and memory consumption.

Malicious node executes BAODV (Black hole AODV) routing algorithm to

avoid black hole attacks. Normal node implements a little bit modified

AODV, called MAODV (Modified AODV), to conduct normal routing.

44

There is no main infrastructure for Mobile ad hoc networks

(MANETs). Hence they are susceptible to malicious network attacks.

Basically security is a more important problem in infrastructure-based

wireless networks. In MANETs, identification of malicious hosts is tedious

because the topology of the network gets changed dynamically and it

interrupts a route that forms a communication path. Hence, many methods

were proposed earlier but they fail to overcome the issue, even they tried with

training data, which usually verifies the identity and topology of the network,

but could not provide a safe routing because of the topology changes.

Hidehisa Nakayama et al (2009) designed a novel anomaly-detection

approach which depends on a dynamic learning process that permits the

training data to get updated at appropriate time intervals. The dynamic

learning method computes the projection distances depending on

multidimensional statistics with the help of weighted coefficients and a

forgetting curve.

In addition to MANET, intra-session network coding is also

naturally unsafe regarding pollution attacks. Anh Le & Athina Markopoulou

(2012) presented a new homomorphic MAC method called SpaceMac, which

permits a central node to confirm whether received packets reside to a exact

subspace or not. A cooperative defense system against pollution attacks was

proposed which was developed based on SpaceMac. Then by using SpaceMac

as a building block a cooperative method that affords entire defense against

pollution attacks is developed. It identifies polluted packets initially at central

nodes and it also finds the appropriate location of all (colluding, attackers)

and makes it probable to remove them. The method is cooperative: corrupted

packets can be identified by the node, with the help of node’s parents and

children. The correct location of all attackers can be detected by the nodes in

the network which is helped with a central controller.

45

Security is the most vital issue that not only affects the MANET but

also affects the VANET. Strong network is needed and must rely on their

security and privacy features. VANETs are facing more problems and

addressed by Ghassan Samara et al (2010). The authors made a study on a set

of solutions proposed for the problems. More attention is made on attacks

executed against the message itself rather than the vehicle. Vehicular Ad Hoc

Networks is a promising technology and it is an abundant region for attackers.

Certificates based safety messages are carried out to provide a safe VANET.

A Trajectory-based Statistical Forwarding (TSF) method is used for

the multihop data delivery from infrastructure nodes (e.g., Internet access

points) to moving vehicles in vehicular ad hoc networks. Jaehoon (Paul)

Jeong et al (2012) made an investigation about the usage of the packet

destination vehicle’s trajectory for such infrastructure-to-vehicle data delivery.

The data delivery is achieved via the computation of a target point with the

help of destination vehicle’s trajectory that is a best meeting point of the

packet. TSF transmit packets with multihop to a chosen goal point where the

vehicle is likely to pass over. The downsides are; the deployment cost has to

be minimized to get better performance by expanding the infrastructure nodes

and efficient way has to be found for better data forwarding in vehicular

networks. The location or position is also affected greatly by VANET.

Vehicle position is important piece of information in a Vehicular

Adhoc NETwork (VANET). Gongjun Yan et al (2007) proposed a new

method to improve position security in VANETs. Local security is obtained by

admitting the support of on-board radar to identify neighboring vehicles and

to verify their declared coordinates. Local security is enhanced to obtain

global security with the usage of preset position-based groups. The radar

performs as the “eye” of the system and confirms the information got from

46

the vehicles within its transmission range. The downside of the method is;

attackers can fire some Sybil attacks whenever the radars sight is blocked.

The attacks also affect the vehicular communications. Generally

vehicular communication troubles combines’ network architecture, protocols

of physical and link layers, routing algorithms and security problems. A.

Singaravelan & Manikandan (2013) presented a study with the various

difficulties in the vehicular ad hoc network communications and provided

solutions for those problems. Most VANET messages are transmitted by

adapting safety messages which must have a broad saturation and must be

delivered in a short time. The messages should be safe and should not leak

personal identification, or linkable information to unapproved parties. Attacks

may involve in sending false information, tracking a location of a vehicle and

jamming the channel for Denial of Service. VANETs security system holds

the features of Authentication & Data Integrity, Anonymity & Availability,

and Low Overhead & Privacy. Nash equilibrium is an important portion and

by using it an efficient VANET is obtained in accordance with cost.

Gireesh Shrimali et al (2010) proposed an advanced method for

interdomain traffic engineering which depends on the ideas of Nash

bargaining and dual decomposition. ISPs employ an iterative method to

jointly enhance a social cost function, denoted as the Nash product. The

global optimization problem is detached into sub problems by offering

suitable shadow prices on the interdomain flows. The sub problems are then

solved separately in a distributed form by the individual ISPs. The presented

technique considerably outperforms unilateral approaches like the generally

employed hot-potato or shortest path routing as well as the Nash equilibrium

setting. Using Nash Equilibrium, ISPs myopically enhance local objectives

when iteratively playing finest feedbacks to each other. Nash equilibrium

routing takes active load-based costs on the links rather than the static weight-

47

based optimization of the hot-potato routing. The Nash equilibrium routing is

an active method; hence it takes numerous iterations to converge which is its

main drawback.

Hao Yu et al (2010) took into account regarding the open-loop

network MIMO system with multiple Base Station (BSs) helping, private

multiple Mobile Station (MSs) and general MS depends on a new partial

cooperation overlaying method. In the network MIMO systems, to alter the

forceful and heterogeneous MIMO configurations, an open-loop overlaying

method is designed. The results obtained when heterogeneous paths employed

among multiple cells are to be determined, so the author designed a

distributive low complexity long-term power allocation algorithm. The

algorithm is designed with verifiable convergence property which only

calculates on local channel statistics. The long-term distributive power

allocation dilemma with the private MSs and the common MSs at all BSs are

also developed with the help of a partial cooperative game. The long-term

power allocation game uses rare Nash Equilibrium (NE) but normal finest

feedback update does not regularly converge to the NE.

Fu-Wen Chen & Jung-Chun Kao (2012) mentioned about the

minimum transmission broadcast issue in wireless networks and presented

efficient solutions which includes an optimal broadcast method and

distributed game-based algorithm. The author considered the problems of

least transmission broadcasting against the reliable and unreliable wireless

links as two mixed integer linear programming (MILP) problems,

respectively. Optimal broadcast method is used in an easier way with the help

of pre existing MILP solver mainly to involve in small-scale networks. For

large-scale networks, a distributed game-based algorithm named Game-Based

Broadcast Tree Construction Algorithm (GB-BTC) algorithm is employed and

it has proved that the game-based algorithm attains better Nash Equilibrium.

48

The broadcast tree construction game meets the Nash Equilibrium in a finite

number of iterations. GB-BTC algorithm behaves extremely well regarding

delivery ratio and the number of transmissions and convergence speed are

also very fast.

Wavelength division multiplexing (WDM) is a technology in optical

networks and it also faces many security related issues. Thus, security

troubles and attack organization in the WDM optical networks is most critical

one to network operators because of the high data rates that are concerned and

the vulnerabilities associated with transparency. Physical-layer attack namely

high-powered jamming damages or reduces the network performance and

must be handled efficiently. Nina Skorin-Kapov et al (2010) had an idea to

route lightpaths in order to reduce the possible damage formed by a variety of

physical-layer attacks. A novel objective standard was proposed for the

routing and wavelength assignment (RWA) difficulty, generally known as

Maximum Lightpath Attack Radius (MaxLAR). MaxLAR has been defined

for the routing subproblem like an integer linear program (ILP). For larger

networks, tabu search algorithm is employed for attack-aware lightpath

routing, along with the usage of preexisting graph-coloring algorithm for

wavelength assignment. Here more cost is involved for LAR and hence

minimum cost with reduced LAR has to be developed.

Thus key based security can also be provided to VANET. Chan

Chen & Michael Jensen (2011) established secret keys to pay attention on the

spatial and temporal interrelationship of the channel coordinates in the simple

wireless channel. An easy single-input single-output channel (SISO) model

generates key size to bind the channel correlation. A multiple-input multiple-

output channel (MIMO) considers decorrelation of the channel coordinates.

Trusted network security is improved on the creation of practical key

generation protocol which is developed on the basis of presented channel

49

coefficient quantization method. In authenticated public channel, the key

agreement in an authenticated public channel is enhanced by involving the

transfer of the correlation eigenvector matrix, flexible quantization levels and

LDPC coding. Channel quantization is effective only on simple channel

model and performance falls short of the achievable bound, hence necessary

steps have to be taken to work with heavy channel model.

The distance-based localization algorithm provides security on

transmission but still the attackers can able to detect the secret data.

Information-theoretic security limitations lower the connectivity of wireless

networks in the existence of listener. The listener existence stimulates a better

modeling of wireless networks. A development of techniques is required to

provide robust security against overhearing. Using physical-layer security

constraints, Xiangyun Zhou et al (2010) formulated the local connectivity of

wireless networks in fading channels. A vital connectivity improvement from

multi-antenna transmission with only two antennas is demonstrated. In

addition, the connectivity degradation from eavesdropper collusion is

quantified. The connectivity is worked locally but a global connectivity is

required.

In cognitive radio networks, an opponent broadcasts signals; their

characteristics should be similar to that of the primary users, basically to stop

secondary users from transmitting. These forms of attack are denoted as the

primary user emulation (PUE) attacks. Primary users normally involve in two

categories of white space and they are; TV towers and wireless microphones.

Shaxun Chen et al (2011) designed a new technique to spot out the PUE

attack that affects the mobile primary users. The correlations among RF

signals and acoustic information are exploited to confirm the presence of

wireless microphones. The correlation among the RF signal and acoustic

signal are presented to distinguish the attackers from absolute wireless

50

microphones. The only downside is that the detection time has to be

minimized when healing white-space devices are present.

Gustavo Marfia et al (2007) proceeded with the study which

depends on realistic vehicular mobility hints of downtown Portland, Oregon,

that are got from particularly accurate large scale traffic simulations

(Los Alamos National Laboratories (LANL)) which was already mentioned

by G. Marfia et al. The mobility model is employed to demonstrate flat and

opportunistic infrastructure routing. The work done by G. Marfia is extended

to determine the impact of a range of mobility models on network

performance. It explains the performance trend that is supposed to happen

during the day as urban mobility patterns get modified. Adjusting the

significance of accurate vehicle density modeling on performance is also

carried out in the work. A uniform vehicle traffic input model (in urban map)

is used to demonstrate the proposed work. The distributions of vehicles

present in the urban map are not very accurate.

Centrality is also to be noted to provide an efficient network.

Betweenness centrality normally depends on shortest paths and it is a normal

measure of control involved in many studies and worked out in all appropriate

software tools for network analysis. Ulrik Brandes (2008) idea was little

different, i.e., quantity of variants which are to be analyzed are stored in the

context and it is significant with easy variants of the algorithm that are

generally employed in the standard case. Different types of betweenness

centrality are considered in which the interest may be in motion, e.g., the

edges, or the range of applicability is elongated to valued networks. For the

variants, small alteration of the used algorithm is employed. The results for

the normal case is the algorithms that are with the similar asymptotic time

complexity (except for length-valued edges), and with similar structure of

computation.

51

Thus, the above said problems can be solved by providing a key

based security. The secret encryption key is not applicable for larger networks

but works well in simpler network but not in a vehicular network; it needs a

greater secure transmission. Tansu Alpcan & Sonja Buchegger (2011) took the

issue into account and proposed an upgraded transportation safety,

consistency, and management in vehicular networks (VANETs). Hence,

within a game-theoretic framework, the security approach of VANETs is

measured. The threats that are caused by malicious attackers are reduced with

the help of defensive measures. The centrality values are in use to find the

centrality measures of the trusted network to the underlying topology. An

optimal formation of security infrastructure and traffic control is measured

both in the static (i.e. fixed roadside units) and dynamic case (i.e. mobile law

enforcement units) states. Multiple categories of security games are proposed

under varying information probability assumptions. Three specific forms of

security games are mentioned under diverse information possibility

hypothesis for the players and they are: payoff is known, payoff is

approximately known and payoff is not known when considering both the

players.

With some advanced method better security is provided by allowing

the vehicles to communicate. Emerging vehicular ad hoc networks (VANETs)

provides facility for the vehicles to talk to all vehicles and it is expected to

improve safety and efficiency in transportation systems. Traffic security and

driver privacy in a large-scale VANET (i.e., metropolitan area) are mostly

affected by attacks which results in scalability and organizational issues. So,

Bo Qin et al (2011) developed an identity-based group signature (IBGS) to

isolate a large-scale VANET into an easily manageable group and create

obligation in vehicular communications while preserving privacy. Human-

recognizable identity of all party’s is used as its public key and no need of any

further certificate which avert the difficult certificate management of present

52

protocols. Further investigation on selfish verification method is carried out in

order to quicken message processing in VANETs.

Thus, Tiffany Hyun-Jin Kim et al (2010) designed a security model

for Vehicular Ad-hoc Networks (VANETs) to distinguish false messages from

real messages. The information present in a VANET environment allows the

vehicles to remove malicious messages that are transmitted by a misbehaving

vehicle. A message filtering technique is also used to control the information

of multiple complementary sources to build a multi-source detection model.

The designed filtering model depends on two factors: a threshold curve and a

Certainty of Event (CoE) curve. A threshold curve denotes an event to a driver

regarding the relative position, and a CoE curve denotes the assurance level of

the received messages.

2.4 REINFORCING SECURITY IN VANET FOR GAME

THEORETIC APPROACH USING VEHICLE MODE

ANALYSIS

As the complexity of commercial cellular networks growth becomes

more automated methods for detecting and diagnosing cells with degraded

performance are needed. Detected anomalies, and root cause analysis are

tedious to identify. P´eter Szil´agyi & Szabolcs Nov´aczki (2012) designed a

new integrated detection and diagnosis framework and it can detect

anomalies, even its root cause is also found. Depending on radio

measurements observation and other performance indicators the anomalies

can be detected. Diagnosis depends on the reports of earlier fault cases by

analyzing and learning their feature impact on diverse performance indicators.

The system must be further evaluated with more Key Performance Indicators

(KPIs) and complex faults.

53

The joint computing environment faces risk in users’ security and

privacy due to the diverse attack routes. Hyun-A Park et al (2010) proposed a

connected authentication and multilevel access control to tackle those

problems and it accords with cryptographic methods in a private database of

“MyLifeBits” system. A method has been proposed which is flexible in

dynamic access authorization, safe against all the attacks from different

routes, a least round of protocol, access control based on privacy security, and

multifunctional. Combination of converging technology and collaborative

computing are the main worry for researchers in network systems and its

environments. In social computing development processes, users play a major

role because they enlarge their requirements to take faultless collaborative

supporting services in their life.

The privacy issue has not left any of the wireless networks and that

includes multihop wireless networks too. Privacy threat is the major difficulty

in multihop wireless networks due to the open wireless medium, in which

traffic analysis and flow tracing are fired effortlessly by a malicious attackers.

Yanfei Fan et al (2011) designed a privacy-preserving method which depends

on network coding that is regarding traffic investigation/flow tracing like size

correlation, time correlation, and message content correlation. Size correlation

is protected by trimming all messages to be of the similar length as same as in

network coding method. Using intrinsic buffering method of network coding,

time correlation can be opposed. Using “mixing” feature of network coding,

message content correlation can be avoided. Two efficient privacy-preserving

techniques are designed namely; intractability of packet flow and

confidentiality of message content. They are employed to prevent traffic

analysis attacks along with homomorphic encoding on Global Encoding

Vectors (GEVs). Computation on incoming messages is achieved by

intermediate nodes with the permission of Network coding. Avoiding attacks

is not sufficient; security must also be enhanced to the traffic analysis.

54

Security has to be provided in ad hoc low power wireless too and

basically for denial of communication at the routing levels. Eugene

Vasserman et al (2013) made an analysis on resource depletion attacks which

occurs mostly at the routing protocol layer which forever exhaust networks by

rapidly exhausting the battery power of the nodes. Among various types of

attacks, vampire attack is most vulnerable attack. The “Vampire” attacks are

always not specialized to any protocol and it mostly depends on the properties

of various forms of routing protocols. Vampire attacks are too hard to identify

and all the protocols are mostly vulnerable to Vampire attacks. A single

vampire utilizes more energy and there is a development in the network-wide

energy usage only at the worst case. But a fully acceptable solution for

Vampire attacks during the topology discovery phase is not found as well as

handling mobile networks is also to be considered.

Security is really crucial in wireless sensor networks. Various

methods have already been presented but they are not to that extend in

contributing security. Hence, a pairwise key distribution is mandatory for

wireless sensor networks because sensor nodes are vulnerable to be

constrained in resources. Taekyoung Kwon et al (2009) proposed a pair wise

key pre-distribution method which is location based. The scheme obtains

higher connectivity and is flexible in resources consumption even in the

presence of errors. Full and random pair wise key predistribution (FRP) uses

deployment knowledge and path key offering method. Key predistribution

with Deployment Knowledge is processed first. Secondly, Shared Key

Discovery (SKD) is employed. Once pair wise keys are not found by SKD,

then extra key establishment is mandatory. After SKD, Path Key

Establishment with Path Key Offering is employed. However, sensor node’s

constrained capabilities are major problems, because public key cryptography

is tough. Achieving higher connectivity is still a great problem because large

55

resources are accompanied and deployment errors can disturb the connectivity

severely.

Providing key based security is not applicable for denial of service

attack. In wireless sensor networks (WSNs) the most vulnerable attacks are

compromised node and denial of service. Review on data delivery technique

has to be made and it is done by Tao Shu et al (2010), which avoid the black

hole creation by these attacks. Classic multipath routing schemes are also

susceptible to these attacks, because of their deterministic nature. The end to

end energy consumption is to be reduced and hence an optimization problem

is used provided with security constraints. Cut around sink attack and source

attack are also involved in the work. The black holes block all paths within

the source and the sink. The cut around sink attack does not allow any secret

share from the source even when disturbed by the adversary. Hence steps are

to be taken to address these attacks.

Thus, encryption based keying concept has to be designed for

providing security against the above mentioned attacks. Developing Cost-

competent, protected network protocols for Wireless Sensor Networks

(WSNs) are a difficult issue as sensors are resource-limited wireless devices.

With the combined protocol in the WSNs, a rekeying transmission is also

required to protect data. Arif Selcuk Uluagac et al (2010) designed an energy-

capable Virtual Energy-Based Encryption and Keying (VEBEK) scheme for

wireless sensor network to extremely decrease the transmission rate that are

necessary for rekeying to prevent false keys. VEBEK controls the transaction

control messages for key renewals and is able to recover more energy by

providing less chat. VEBEK employs single key for one message so

consecutive packets of the stream employs diverse keys. VEBEK unbundled

key generation from security services by supporting a flexible modular

56

architecture for an easy adoption of various key-based encryption or hashing

schemes. VEBEK is unable to identify the dynamic paths and insider threats.

Hence, security is mandatory for contributing the communication

within the sensor node which belongs to the same network and not from

outside intruder or attacker. Many protocols are designed to provide security

in WSN but no one offered a better result. So, Mojtaba Ghanaat Pisheh Sanaei

et al (2013) selected the recent two protocols named Secure Real-Time with

Load Distribution (SRTLD) and Biological Inspired Self-Organized Secure

Autonomous Routing Protocol (BIOSARP) for critical analysis and

investigation. In WSN environment circumstance which is already attacked,

under eight malicious nodes and four source nodes with heavy network load,

BIOSARP utilized less energy than SRTLD. BIOSARP delivery ratio is better

and high. The delivery ratio of SRTLD is reduced because of the huge

broadcast at every hop. Hence, BIOSARP performance in heavily loaded

WSN is high and lessens the attack that affects the real time WSN because of

its autonomous and self-optimized functionality.

In a MANET there is no presence of devoted routers and all network

nodes are committed for routing. MANETs are greatly affected by the attacks

mostly by passive and active attacks. The passive attacks deal with retrieval of

information, while the active attack deals with malicious nodes. Active attacks

normally depend on modification, impersonation/spoofing, fabrication,

wormhole, and selfish behavior. An overview is made on them by Jonny

Karlsson et al (2012). The significance of cryptography and trust in secure

MANET routing is also mentioned with the help of appropriate security

extensions of existing routing protocols for MANETs.

Security will get spoiled not only because of attacks but also due to

cheating beacon nodes. Secure distance-based localization in the existence of

cheating beacon nodes is a vital complication in mobile wireless ad hoc and

57

sensor networks. Murtuza Jadliwala et al (2010) presented a localization

algorithms based on distance that belong to the group of bounded error

localization algorithms. The proposed algorithm promises a bounded

localization error when the quantity of cheating beacons is lower than the

threshold. As the quantity of cheating beacon nodes is higher than or

equivalent to a specified threshold then there is no chance of existence of two-

dimensionality of proposed algorithms and may lead to a bounded error.

Alternatively when the quantity of cheating beacons is lower than the

threshold, a class of proposed algorithms is identified that always lead to a

bounded localization error.

Game based approach is not only applicable to provide security in

VANET but also for accessing spectrum in CR networks. Dapeng Li

et al (2011) used a new context for Cognitive Radio (CR) networks to allow

multiple operators to include secondary users (SUs) as cooperative relays for

their primary users. Hence, SUs get a chance to access spare channels for their

own data transmission. Initially, assumption is made that the CR network

supports payment transfer. Then, the system is defined as a transferable utility

coalitional game. There is the presence of operating point which increases the

sum utility against all operators and SUs, when share is provided for all

players. Hence no subset of operators and SUs has a motivation to split away

from the grand coalition. The operating points exist only during the solution

set of the game (the core) is nonempty. An interesting situation mentioned as;

in the network, there is no payment technique was investigated by the usage

of nontransferable utility coalitional game model. A joint action is used to

make the core nonempty.

Denial of service attack is an important issue and it affects the

wireless mesh networks (WMN) too. Devu Manikantan Shila et al (2010)

took into account the denial of service (DoS) attack in WMN denoted as

58

selective forwarding attack (gray hole attacks). In the presence of the attack, a

mischievous mesh router forwards a subset of the packets received and drops

the others. The author considered that a packet dropping occurs because of an

attack or regular loss events (average access clash or worst channel quality). A

channel aware detection (CAD) algorithm is proposed which adequately

detected the selective forwarding misdeed from the standard channel losses.

The CAD algorithm depends on two approaches namely; channel evaluation

and traffic observation. The loss rate was observed at specific hops and when

it goes beyond the expected normal loss rate, then those nodes that are

included was recognized as attackers. The downside of the work is that when

an attacker proposes noise to reproduce a noisy channel, it further affects the

sensing process and that leads to mistaken threshold. Hence, these attacks are

to be avoided by extending CAD or by development of some other efficient

method.

Next, secured communication and protection against the adversary

attacker interruption have to be provided in vehicular network too. Ghassan

Samara et al (2010) provided it. The secured VANET provides a satisfactory

level in broadcasting messages by comforting the level of drivers and

manufactures for a smooth and safe life. An analysis on the numerous

categories of security difficulties and challenges of VANET are made. Also a

solution is provided to the security problems and challenges based on the

analysis. The solution provided for VANET security ensures the message

received is valid. A huge analysis for the VANET security challenges is

solved. Limitation for the analysis is carried out in future along with the

simulation test to maintain a secure VANET network. Public key based

security can also be provided in VANET along with the revocation list.

Vehicular Ad Hoc Networks (VANETs) involves Public Key

Infrastructure (PKI) and Certificate Revocation Lists (CRLs) to consistently

59

secure the network. In PKI system, the authentication of a received message is

achieved by inspecting the certificate of the sender i.e., the certificate should

not be present in the current CRL. Albert Wasef & Xuemin (Sherman) Shen

(2009) designed a Message Authentication Acceleration (MAAC) protocol for

VANETs that alters the time-consuming CRL checking process with a capable

revocation check process. A keyed Hash Message Authentication Code

(HMAC) is used by the revocation verify method, where the key computes

whether the HMAC is shared merely among non-revoked On- Board Units

(OBUs) or not. The MAAC protocol also involves a new probabilistic key

distribution, which permits non-revoked OBUs to securely share and update a

secret key. Furthermore, the downsides of the MAAC are challenging to

attacks regarding to authentication methods that are employing the

conventional CRL. Certificate and message signature authentication are also

needed to be provided. Some other authors took into account the mentioned

drawback and provided a better result.

A better mechanism is needed for Vehicular Ad Hoc Networks

(VANETs) to provide an authenticated message, to detect valid vehicles, and

eliminate malicious vehicles. A Public Key Infrastructure (PKI) can be

employed to obtain this functionality with the help of certificates and fixed

public keys. But fixed keys permit a listener to relate a key with a vehicle and

a location, which will oppose the drivers’ privacy. Ahren Studer et al (2008)

presented a VANET key management method that depends on Temporary

Anonymous Certified Keys (TACKs). Temporary Anonymous Certified Keys

(TACKs) is a capable method that satisfies the security and privacy

properties. They are important for key management in Vehicular Ad Hoc

Networks (VANETs). In TACKs, On-Board Units (OBUs) use short-lived

keys for signing the messages for VANET communication and those short-

lived keys are authorized by Regional Authorities (RAs).

60

VANET is a scheme of Mobile Ad-Hoc Network (MANET).

VANET has high mobility of nodes and the huge scale of networks. The

increasing amount of promising applications is in association with intelligent

transportation systems (ITSs) and involves many investigators to the area of

vehicular networks (VNs). The applications have been provided with security,

scalable, protection, and knowledge about traffic and service location

applications. Rajadurai & Jayalakshmi (2013) made a discussion on the

challenges and attacks to vehicular networks and solutions afforded to some

of the challenges. Two groups of protocols namely LocVSDPs and GeoVCom

are established and recommended a group of resolution to the development of

security in VANET. Hence to provide security, the vehicle behaves like a

communication node that swaps data to protect the collision prevention and

accident warning, and offers services like traffic information, breakdown, fuel

services and office locations. The protocol improves the scalability in VANET

and security is provided with the usage of Vehicular Public Key Infrastructure

(VPKI), Group Signature, and Regional trusted authority.

Thus, safety must not only be provided to vehicles but also to

passenger and that is also to be considered. Intelligent Transportation Systems

(ITS) enhance passenger safety and transportation efficiency by the usage of

vehicle-to-vehicle and vehicle-to-roadside wireless communication

technologies. Communication protocols in these environments meet delay

conditions because of the high moving speed of the vehicles. Shan-Hung Wu

et al (2010) designed an energy conservative MAC layer protocol, denoted as

Dedicated Short Range Communications Asymmetric and Asynchronous

wakeup (DSRC-AA), based on IEEE 802.11. DSRC-AA saves the power for

ITS communication modules like On Board Units, portable devices, and Road

Side Units, while establishing the bounded delay. DSRC-AA, an overview of

the Asynchronous Quorum-based Power-Saving (AQPS) protocols, exploits

61

the clustering nature of moving vehicles and allocates diverse wake-up/sleep

schedules to the cluster head and the representatives of a cluster.

Neng-Wen Wang et al (2008) made a analysis on the secure

infrastructures that are proposed earlier for VANET, which has possible

applications and motivating security challenges. A new secure method for

vehicular communication on VANETs is also proposed to overcome the

security challenges. The presented method safeguards the privacy and also

controls the liability in the secure communications with the help of session

keys. The robustness of the method is also analyzed. Inter-Vehicular

Communication (IVC) is a basic characteristic of the forthcoming intelligent

transportation systems and its vital permissive component of IVC is its

security services.

Many novel applications are predicted, which will enhance traffic

management and safety in VANET. These applications have demanding

security requirements; they also alter road traffic safety. VANETs face

numerous security threats. VANETs offer some different features like high

mobility of nodes, geographic extension, etc., and conventional security

techniques are not frequently applicable. Hence, José María de Fuentes et al

(2010) planned to define and evaluate the most representative VANET

security developments. A general underlying model for the above mentioned

type of network has been introduced with the use of its main settings. The

security requirements which are present in all VANET setting have been

identified. Apart from typical security needs like confidentiality, other

context-specific ones are also present for e.g. trust assurance over reported

data.

From VANET the security issue has traversed in Vehicular sensor

networks too and they are shared environments where mobile vehicles are

supplied with sensors of diverse nature and inter-work to execute monitoring

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applications. Proactive urban monitoring is an emerging trend where vehicles

steadily sense events from urban streets and separately process sensed data

e.g., recognizing license plates, and perhaps route messages to vehicles in

their neighborhood to attain the common objective. Thus, the challenging

environment needs new solutions along with the traditional wireless sensor

nodes. So, Uichin Lee et al (2009) gave a description about MobEyes, an

efficient middleware purposely designed for proactive urban monitoring,

which makes use of node mobility to opportunistically spread sensed data

analysis among neighbor vehicles.

Then it also attacked the Vehicular Ad hoc Network, which is an

assemblage of mobile hosts establishing a temporary network without the help

of any traditional infrastructure. VANETs are mostly subjected to attacks

because of their susceptibilities. Sybil nodes attack is the most compromising

attack among various attacks. Mohamed Salah Bouassida et al (2009)

proposed a Sybil detection method depending on received signal strength

variations, i.e., permitting a node to identify the authenticity of other

communicating nodes, according to their localizations. A predictable metric of

the distinguish ability degree among two nodes that are permitting to resolve

Sybil and mischievous ones within VANET are also defined.

Hence an enhanced method is proposed for Sybil attacks by some

other author and he proposed it for all system to avoid intrusion of Sybil

attack. Open-access distributed systems like peer-to-peer systems are mainly

susceptible to Sybil attacks, where a malicious user develops multiple fake

identities (called Sybil nodes). The SybilGuard protocol has an influence on

social networks to bind the number of Sybil nodes are acknowledged.

SybilGuard permits a large number of sybil nodes that are to be accepted.

Furthermore, SybilGuard consider that the social networks are fast-mixing

and that is not confirmed in the real world. Haifeng Yu et al (2010) designed a

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novel SybilLimit protocol that influences the same as SybilGuard, but

provides dramatically enhanced and near-optimal guarantees. Three large-

scale real-worlds public networks are present and the evidence for such

networks are indeed fast-mixing. Validation for the fundamental statement

after SybilLimit’s and SybilGuard’s method has been proved.

Security and Privacy are most vital matters in Vehicular Ad-hoc

Networks (VANET). Usage of pseudonyms is the extensively approved

privacy preserving communication method in VANET. Pseudonyms have

provided great solutions for security problems like Sybil attack. Reza

Mortazavi Maryam Rahbari (2011) designed an efficient method to detect

Sybil attack during the privacy preserving of vehicles in the network.

Distributed and hierarchical method has also been developed that meets all

security requirements of VANET. The proposed method is more efficient and

robust against probable attacks when compared with other similar methods.

The number of attackers has got much more limited, and a global privacy

attack is approximately infeasible.

Privacy-preserving methods in VANET are mostly susceptible to

Sybil attacks, where a malicious user can act as if a multiple (other) vehicle.

Tong Zhou et al (2011) proposed a lightweight and scalable protocol called

Privacy Preserving Detection of Abuses of Pseudonyms (P2DAP) to identify

Sybil attacks. In the proposed protocol a malicious user acts as multiple

(other) vehicle is detected in a distributed manner by the help of passive

overhearing by a group of fixed nodes denoted as road-side boxes (RSBs).

The discovery of Sybil attacks by the above mentioned form does not

necessitate any vehicle in the network to reveal its identity by which privacy

is safeguarded at all times. The downside in P2DAP is that the ratio and

activities of mischievous vehicles are not predicted; hence for that a machine

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learning algorithm has to be developed. If the attackers are found, then

P2DAP can identify attackers with more minimized overhead and delay.

Besides the security and privacy in VANET, usage of Nash

equilibrium is most important as it provides an efficient VANET. Gireesh

Shrimali et al (2010) proposed a novel method for interdomain traffic

engineering and it depends on Nash bargaining and dual decomposition. The

Nash product is a social cost function and it is enhanced by ISPs which use an

iterative method. The global optimization problem is partitioned into sub

problems by offering suitable shadow prices on the interdomain flows. The

sub problems are then solved separately in a distributed form by the

individual ISPs. The proposed method considerably outperforms than the

commonly used hot-potato or shortest path routing as well as the Nash

equilibrium setting. Nash equilibrium routing takes active load-based costs on

the links rather than the static weight-based optimization of the hot-potato

routing. The Nash equilibrium routing is an active method; it takes numerous

iterations to converge which is the drawback.

The above said problem can be solved by the usage of centrality

measures but there is no guarantee for good result. Vehicular network is a

simpler network and needs more secured transmission. Tansu Alpcan & Sonja

Buchegger (2011) proposed an upgraded transportation security, reliability,

and management in vehicular networks (VANETs). A game-theoretic

framework is employed and by which the security approach of VANETs is

measured. The threats caused by malicious attackers are reduced with the help

of defensive measures. In the underlying topology the centrality measures of

the trusted network is found with the help of centrality values. A best

development of security infrastructure and traffic control is measured both in

the static (i.e. fixed roadside units) and dynamic (i.e. mobile law enforcement

units) states. Under differing information probability assumptions, different

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categories of security games can be proposed. Three specific forms of security

games are mentioned and they are; payoff is known, payoff is approximately

known and payoff is not known when considering both the players.

Thus one of the mentioned forms of security games has been

utilized for better end to end messaging. Because of no end-to-end

connections in VANET, nodes utilize the chance and starts to forward

messages in order to make end-to-end messaging efficient. Thus it is

important that nodes must have motivation to forward messages to others.

Tingting Chen et al (2010) presented a study to activate message forwarding

in VANETs and the approach depends on coalitional game theory. The

incentive method controls the storage space that contains the details of each

node. The architecture of the incentive method is designed first and a payoff

allocation technique is introduced which is utilized in the incentive method.

The incentive method formed using payoff allocation gave a solution for the

cheating of inter-vehicle communication of incentive method with errors.

Security can also be employed in VANET with the usage of

cryptography schemes which may provide better results. In Vehicular Ad-hoc

Networks (VANETs) for secure data broadcasting, solutions are to be

employed and for that robust cryptography methods are used. It is used better

than more lightweight, trust-based methods because they face severe

problems such as illusion, collusion and Sybil attacks. Esther Palomar

et al (2011) presented a paper that shows the possibility to hinder the diffusion

of false warning events in VANETs. It reduces the amount of messages a node

can transfer within a specified time period by applying well-known

cryptographic techniques. The proposed method depends on two easy

concepts in order to provide accountability and to conflict with spam and

denial of service attacks. They use certificates and Proof-of-Work (POW)

systems correspondingly. The method also provides an effective non-

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repudiation confirmation for diverse types of dishonest behavior of nodes

within a VANET.

2.5 RESEARCH GAP

In Distributed Certificate Service (DCS) method the only drawback

is that the revocation problem is to be considered and solved. Mostly the

security problem is due to the revocation of misbehaving vehicles. Steps are

to be taken for the avoidance of malicious vehicles from risking the safety of

other vehicles. The other issue in wireless networks is that security is to be

provided for the received messages with respect to their correctness degree

and activate the revocation process for a misbehaving vehicle that is

transmitting malicious messages.

A better solution for Vampire attacks during the topology discovery

phase is not found as well as handling mobile networks are also to be

considered. The cut around sink attack is a most crucial attack which is

disturbed by the adversary, so steps are to be taken to address these attacks.

Unobservable Secure On-Demand Routing (USOR) protocol is employed to

provide security from attacks, but the downside is that USOR is still affected

by wormhole attacks, black hole attacks and DoS attacks which is a

challenging task.

The deployment cost will be mostly high and it has to be minimized

to get the expected performance by expanding the infrastructure nodes. An

efficient way has to be found for better data forwarding in vehicular networks.

The location or position is also affected greatly by VANET. Location based

security is also to be provided for secure VANET and it has been provided by

earlier method but the downsides in that are; attackers normally launches

some Sybil attacks whenever the radars sight is blocked.

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The Nash equilibrium routing is an active method; but it takes

numerous iterations to converge which is its drawback. Achieving higher

connectivity is still a great problem because large resources are accompanied

and deployment errors can disturb the connectivity severely. The major

drawback in vehicular sensor network is that when an attacker proposes noise

to reproduce a noisy channel, it further affects the sensing process and that

leads to mistaken threshold. The downside in P2DAP is that the ratio and

activities of mischievous vehicles are not predicted.

2.6 CONTRIBUTIONS OF THESIS

Security lacks in VANET because of the attack, and hence effective

method has to be proposed to provide a secure VANET. Thus, in our proposed

method security is provided based on game theoretic approach. The Heuristic-

based Ant Colony Optimization technique is proposed and it has greatly

improved the game theoretic approaches for VANET security. The centrality

measures are employed in security games in order to provide more security.

The attacker’s behavior is reduced by the usage of proposed technique.

Malicious nodes formation is minimized and the method produced a good

network.

Nash equilibrium along with MC (Markov Chains) is the presented

method to upgrade the game theoretic model for security related issues in

VANET. The security issues are greatly reduced because the Nash equilibrium

performs efficiently which depends on game theory. The Nash equilibrium in

the proposed method involves less iteration for convergence. The ratio and

activities of mischievous nodes are also found which provided an efficient

result by producing minimized delay and overhead because the ratio of the

attacker was known.

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A new method for providing security is introduced and it consists of

a skeleton for mode analysis modules using which the effectiveness and trust

of the vehicle is determined in road network path. Three statuses are denoted

by the model and provided it effectively; they are reliable, unreliable and

impartial vehicles. The misbehavior of the opponents involved in the game is

identified and avoided by the proposed method. The scheme combines both

the heuristic based ant-colony optimization and Nash Equilibrium integrated

Markov Chain for the enhancement of the VANET security. Thus security is

provided for VANET by using the proposed method which is based on game

theoretic approach and they are efficiently secure.