research article a group based key sharing and management...

Research ArticleA Group Based Key Sharing and Management Algorithm forVehicular Ad Hoc Networks

Zeeshan Shafi Khan,1 Mohammed Morsi Moharram,2 Abdullah Alaraj,3 and Farzana Azam4

1 University Institute of Information Technology, PMAS Arid Agriculture University, Rawalpindi 46000, Pakistan2 College of Computer and Information Science, Al ImamMuhammed Ibn Saud Islamic University, Riadyh 11187, Saudi Arabia3 Qassim University, Qassim 51431, Saudi Arabia4Qassim Colleges, Qassim 51452, Saudi Arabia

Correspondence should be addressed to Zeeshan Shafi Khan; [email protected]

Received 28 August 2013; Accepted 28 October 2013; Published 22 January 2014

Academic Editors: P. Melin and Z. Shi

Copyright © 2014 Zeeshan Shafi Khan et al. This is an open access article distributed under the Creative Commons AttributionLicense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properlycited.

Vehicular ad hoc networks (VANETs) are one special type of ad hoc networks that involves vehicles on roads. Typically like adhoc networks, broadcast approach is used for data dissemination. Blind broadcast to each and every node results in exchange ofuseless and irrelevant messages and hence creates an overhead. Unicasting is not preferred in ad-hoc networks due to the dynamictopology and the resource requirements as compared to broadcasting. Simple broadcasting techniques create several problems onprivacy, disturbance, and resource utilization. In this paper, we proposemediamixing algorithm to decide what information shouldbe provided to each user and how to provide such information. Results obtained through simulation show that fewer number ofkeys are needed to share compared to simple broadcasting. Privacy is also enhanced through this approach.

1. Introduction

Vehicular ad hoc networks (VANETs) are the most popularapplication of wireless communication technologies. Vehicleto vehicle [1] and vehicle to roadside [2] enable the passengersto share safety and comfort information [3]. Traffic manage-ment, collision avoidance, and safety warnings are the safetyapplications [4]. The comfort application [5] gives facilityto passenger by sharing information like parking or hotelinformation and petrol or gas station information. Security isalso an essential requirement in VANETs. Jayachandran andManikandan [6] explain communication and its techniquesof broadcast that are mainly used in VANETs.

Mobile ad hoc networks (MANETs) are gaining extraor-dinary attention by researchers as well as by the industri-als. Vehicular Ad-hoc Networks (VANETs) are one specialapplication of MANETs. MANETs are infrastructureless net-works that do not require any specialized devices for setup.Nodes act as an end user and a router at the same time.Within the radio range, nodes use the wireless medium tocommunicate with each other. MANETs are extremely useful

in the situations in which it is not feasible to set up a hugeinfrastructure. Ad hoc networks can be quickly deployedwithno administrator involvement. It is very difficult to managea network of millions of vehicular nodes so these reasonscontribute to the ad hoc networks being applied to vehicularenvironments.

Germany is working on FleetNet project that is purelybased on VANETs and it is among the biggest projects of theworld. Similarly Japan has started a VANET based projectwith the name of ITS project. VANETs are gaining popularityalong the globe. There are few other names of VANETsgiven by various well-known organizations. These names areintervehicle communication (IVC), dedicated short rangecommunication (DSRC), or WAVE. In future, it is claimedthat journey on highway will become more secure and ratioof accidents will dramatically decrease by using VANETs.

While you are driving, you are constantly changing yourlocation. Change of location changes all the surroundinginformation. This information can be divided into differentcategories. The most important category is about driver andvehicle safety information like sharp turns, accidents ahead,

Hindawi Publishing Corporatione Scientific World JournalVolume 2014, Article ID 740216, 8 pageshttp://dx.doi.org/10.1155/2014/740216

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road conditions, weather forecast, speed limits, traffic jam,jumps, and railway tracks.

Infotainment is another category in which nearby vehi-cles can share Internet access, play games, and so forth. Pro-viding parking information is another category of VANETinformation. Car maintenance information is another cate-gory in which vehicles can provide information to each otherabout automobile workshops, car mechanics, and so forth.

VANET is mostly configured for sharing safety messagesfrom vehicle to vehicle. There are some scenarios in whichgroup communication is also required by the vehicles. In caseof police patrolling, car racing, and tour travelling, the groupof vehicles will require sharing information without disclos-ing it to vehicles outside the group. Group formulation, groupmanagement, and key exchange are the issues which requiredspecial attention before starting group communication. Inthis paper, we formulated amediamixing technique, throughwhich vehicles formulate and join the groups, exchangethe keys, and manage the group in case of joining andleaving the network. Simulation results showed that theproposed technique performs better as compared to existingtechniques.

In the next section, work related to data disseminationand broadcasting is reviewed. Problems are also described atthe end of the section.The third section provides details aboutthe media mixing algorithm and its working. The fourth sec-tion presents simulation results for performance validation ofthe proposedmediamixing technique. Last section concludesthe paper and provides few future directions.

2. Related Work

In simple flooding each message is blindly sent to allthe nodes of the network. This creates several problemslike redundancy and collision [7]. Probabilistic scheme [8]calculates the probability and sends messages on the basisof that probability. If the probability is increased, it worksmuch like flooding [9, 10]. Counter based technique reducesthe redundancy of messages [7]. Distance based schemefirst calculates the distance between itself and its neighborvehicles.Then, it compares the distance with threshold. If thedistance is greater than a threshold, it forwards the packet;otherwise, it ignores the message [9, 10]. Location basedscheme first calculates the coverage area with help of senderlocation. The vehicle will ignore the packet if area is smallerthan a threshold value; otherwise, the packetwill be broadcast[11]. Neighbor knowledge methods [12] maintain a table thatcontains the information of its neighbor node. A vehicledecision depends upon this information to forward messageor not. Broadcast can also be done by using trees. But it is notfit for ad hoc networks, due to the dynamic nature.

Urban multihop broadcast protocol (UMB) is proposedto resolves the reliability, broadcast storm, and hidden nodeproblems, without sharing information among the vehicles.Directional broadcast and intersection broadcast are thetwo main steps of UMB [13]. Source vehicle selects thefurthest vehicle for communication in direction broadcastwhere as in intersection broadcast installed repeaters at road

segments forward the packets to destinations. A mobility-centric data dissemination algorithm for vehicular networks(MDDV) is a mobility centric scheme that merges the idea ofopportunistic, trajectory, and geographical forwarding [14].Trajectory based forwarding [15] is a scheme to forwardthe packets along a predefined curve in dense vehicular adhoc network. Geographical forwarding is used for routingdecisions. To forward packet to the destination, a vehiclebroadcasts the packet to a vehicle that is near to the des-tination [16]. An opportunistic forwarding [17] has threefunctions (store, copy, and forward), which give rise toepidemic spreading. MDDV enhance the delivery efficiencyand solve the broadcast storm problem. But it still has someshortcoming that it does not differentiate between messagetypes and forward surplus messages without knowing theirrelevance. Relevance based approach is designed for vehicularad hoc network as the speed of vehicles is very high andthey have limited time to exchange message so they forwardonly relevant and important messages and discard the lowpriority messages. Relevance based approach methodology[18] is defined as follows: first we compute the relevancevalue of message with the help of three resources (vehiclecontext, message context, and information context) and thenwe allocate the medium to the messages according to theirimportance. In this way, low priority traffic cannot get themedium more than high priority traffic. Relevance schemehas certain drawbacks that it does not provide internalresorting of packet queue using 802.11e [19] and it considersthe ideal situation that all vehicles are reliable and error free,no concept of malicious node, as it is not possible in realscenarios. Multihop vehicular broadcast (MHVB) [7] usestwo algorithms, that is, congestion detection and backfirealgorithm.With the help of CongestionDetection, it removessurplus messages and sends packet to destination by usingBackfire algorithm.

An adaptive broadcast protocol [20] is proposed toimprove the message reliability in VANETs scenario. But itstill has to face many challenges like hidden node problemand no priority mechanism in VANETs for providing reliablebroadcast. Sequence numbers of packets are useful in orderto analyze the network congestion.With the help of sequencenumber, vehicles dynamically adjust the contention windowand improve the performance.

Alam et al., in 2006, proposed the idea of narrowcasting.According to them, instead of sending media burst to allthe participants of the conference, it should be deliveredaccording to the preferences of the sender and receivers.Each participant can configure his/her preferences that towhom he/she wants to send her voice and to whom shedoes not want to [20]. Zeeshan et al., in 2011, presented amedia mixing algorithm to push multimedia service in IPmultimedia subsystem. Their mechanism works on similarparameters but they purely developed it to push multimediaservice [21]. Ahmed et al., in 2009, worked on performanceevaluation of different broadcast techniques forVANETs [22].

There hardly exists any single solution that allows theVANETs based vehicles to securely form the group, toestablish and share the cryptographic keys, and tomanage thegroup in case of joining of new nodes or excluding of existing

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nodes. So we need a solution that formulates the group ofvehicles of similar interest, treats the incoming and outgoingvehicles efficiently, and securely keeps the privacy.

3. Proposed Solution and Methodology:Media Mixing Algorithm

In this paper, we developed a media mixing algorithm toshare the keys among the nodes of the ad hoc network. Theobjective of this research is to share only the relevant informa-tion among the users. Moreover, privacy is also consideredas a key parameter in this research work. We design threescenarios to elaborate the media mixing algorithm. Scenarioone discusses the normal communication among the existingnodes of the ad hoc network when a network is initiated orcreated. Scenario two covers the situation when a new nodejoins the network. The third scenario discusses the case inwhich an existing node leaves the network.

3.1. Scenario 1: Network Initiation. At the time of networkcreation, each and every node sends its preferences to roadside unit (RSU) in form of send/receive list by using PKI.This is based on the assumption that the nodes which wantto form the group have knowledge about each other. Weassume that every node has information about the existenceof all other nodes of the network. The other information thatnodes share with the RSU is about how to treat the newnodes. Either a node will allow the new incoming nodesto communicate with it or the node will restrict the newnode to communicate with it. The RSU applies media mixingalgorithm on this send/receive list and formulates a final listthat includes who want to communicate with whom. On thebasis of this final list, it creates groups and allocates IDs toeach group since each node can belong to many groups at atime. Every node has as many keys as many groups it belongsto. These session keys and group IDs are then forwarded toeach node using PKI. Each node has one send session key andas many receiving keys as many nodes are in its send list.

Whenever a node wants to send any piece of information,it prepares the message, encrypts it with its send sessionkey, and adds some additional information with it. Thisadditional information includes message ID, group ID, andhash of the first two. At the end, sender signs the message.Accordingly, whenever a node receives a message it firstverifies the signature of the sender, and then it checksmessageID in order to ensure that previously it has not received thesamemessage. If it finds that it has already received amessagewith the same ID, themessage will be discarded. Otherwise, itwill continue processing. Next step is to check the group ID inorder to ensure that whether themessage belongs to this nodeor this node is only acting as relay node. For this purpose,every node maintains a history of IDs of received messagesup to a specific period of time that may vary from scenarioto scenario. If group ID matches with any group ID of thereceiver, it means that this message belongs to this node;otherwise, the receiver will simply forward themessage. Hashis checked in order to ensure that Message ID and Group IDare not corrupted in transit. Figure 1 shows the architecture

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Figure 1: Media mixing algorithm.

and detailed communication steps involved in media mixingalgorithm.

The following are the few abbreviations that we will usein the algorithm below:

PbR: public key of road side unit;PbN: public key of particular node;SSK: send session key;PvN: private key of a particular node.

Step 1: user sends preferences by encrypting them throughpublic key of RSU (send to/receive from preferencesto RSU) PbR.

Step 2: RSU applies media mixing algorithm:

Step 2.1: identify the associated groups of each node;Step 2.2: generate session keys;Step 2.3: allocate group IDs (group IDs ≤ number of

total nodes in the network).

Step 3: send relevant session keys and group IDs to thenodes by encrypting themwith each node’s public key(session keys + group IDs) PbN.

Step 4: a node prepares a message:

Step 4.1: message is encrypted with send session key(message) SSK;

Step 4.2: group ID, Message ID, and Hash ID areattached with the message [{(Message)SSK}Group ID, Message ID, and Hash];

Step 4.3: sender signs the message with its privateID [{(Message)SSK}Group ID,Message ID, andHash] PvN.


Table 1: User’s preferences.

User Send to Receive from Criteria for new nodeA C, D, F, P, S B, C, D, E, F, G, Q, P, S N, NB A, C, P, S A, C, P, S N, YC A, B, D, F, P, S A, B, D, E, F, G, Q, P, S N, YD A, B, C, E, F, G, Q, P, S A, B, C, F, S Y, YE A, B, G, P, S A, B, G, P, S Y, NF B, C, D, G, Q A, B, D, E, G, Q Y, YG A, B, C, D, E, F, Q, P, S A, B, C, D, E, F, Q, P, S Y, NQ A, B, C, D, E, F, G, P, S A, B, C, D N, YP B, C, D, F, G B, C, D, F, G, Q N, YS A, B, C, D, E, F, G, Q, P C, F, G, Q Y, N

Table 2: Application of media mixing algorithm on user’s preferences.

User Send to Receive fromA C, D, F B, C, D, E, G, Q, SB A, C, P C, P, SC A, B, D, P, S A, B, D, F, G, Q, P, SD A, C, F, G, Q, P A, C, F, SE A, G GF C, D, G A, D, G, QG A, C, E, F, P, S E, F, Q, P, SQ A, C, F, G, P, S DP B, C, G B, C, D, G, QS A, B, C, D, E, G C, G, Q

Step 5: receiver receives a message:

Step 5.1: verify signature; if not verified, discard themessage; else go to Step 5.2;

Step 5.2: verifymessage ID; if it already exists, discardthe message; else go to Step 5.3;

Step 5.3: verify Hash; if not verified, discard themessage; else go to Step 5.4;

Step 5.4: check group ID:Step 5.4.1: if ID is matched, decrypt the message

and also forward the receivedmessage as is;Step 5.4.2: if ID is mismatched, forward the

packets as it is.

In Table 1, we take a network of 10 nodes. Every nodesends its send/receive rules to RSU as shown in the “Send to”and “Receive from” fields of Table 1. The third informationis about treating a new incoming node. “N” shows that newnodes are not allowed to communicate while “Y” shows thatnew nodes are allowed to communicate.The first value in thatcolumn shows the “Send to” and the second value shows the“Receive from.”

In Table 2, media mixing algorithm is applied on user’spreferences (Send to/Receive from rules of Table 1). In caseof clash, priority is given to the Receive from rule whenevera node wants to send data to another node but this node isnot willing to receive data from that particular sending node;then the data will not be delivered as the “Receive from” rule

has priority over “Send to” rule. After applying the mediamixing algorithm we get the results in Table 2. Media mixingalgorithm removes all the anomalies existing in Table 1.

In Table 3, we allocate the group IDs to the nodes. Thetotal numbers of groups are equal to the total number ofnodes in the network. A single node can be part of multiplegroups at a time. In Table 3, we also show how many keysare needed to share with each node of the network. The lastcolumn of Table 3 represents this information. It can be seenthat user A needs total 8 keys. First key is the “send sessionkey” of the user A which will be used to encrypt any datasent by user A. Since user A is receiving data from 7 othernodes so it needs to share session keys of those 7 nodes withuser A. User A will not get session keys of the nodes withwhom it does not want to share data like nodes F and P. So anyinformation sent by user F or P will not be delivered to user Abecause it is not relevant to user A. In this way, we achievedsharing of only the relevant information. On one side, thismechanism saves the valuable resources and on the other sideit enhances the privacy within the ad hoc network.

3.2. Scenario 2: Joining of a New Node. Whenever a newnode joins the networks it also sends its own send/receivepreferences to RSU. Table 4 shows the Send to/Receive frompreferences of a new node Z along with the preferences ofdealing with new nodes.

After getting the preferences of node Z, the RSU againapplies the media mixing algorithm. It scans the “criteria for


Table 3: Group IDs and session keys for each node.

User Group ID Send to Receive from Session keysA 1 C, D, F B, C, D, E, G, Q, S 1 + 7B 2 A, C, P C, P, S 1 + 3C 3 A, B, D, P, S A, B, D, F, G, Q, P, S 1 + 8D 4 A, C, F, G, Q, P A, C, F, S 1 + 4E 5 A, G G 1 + 1F 6 C, D, G A, D, G, Q 1 + 4G 7 A, C, E, F, P, S E, F, Q, P, S 1 + 5Q 8 A, C, F, G, P, S D 1 + 1P 9 B, C, G B, C, D, G, Q 1 + 5S 10 A, B, C, D, E, G C, G, Q 1 + 3

Table 4: Send to/receive from preferences of a new node Z.

User Send to Receive from Criteria for new nodeZ A, B, C, D, E, P, S A, B, C, D, P, S Y, Y

new node” of all the existing nodes. If a node allows the newnode to receive any data from it, then it is matched with the“Receive from” column of the new node in order to ensurewhether new node is willing to receive from this node or not.For example, if we look at Table 1, we will find that node A isneither willing to send data to any new node nor willing toreceive data from any new node. So node Z cannot have A inits “Send to” and “Receive from” list. Node B is not willing tosend any data to a new node but it is ready to receive any datafromanewnode as shown inTable 1.Mediamixing algorithmwill check “Send to” preferences of node Z and will find thatnode Z is willing to send data to node B so node Bwill be fixedin “Send to” list of node Z.The number of groups and numberof keys shared with every node will also change by adding anew node in the network. Table 2 is modified by adding thenew node and the final results are shown in Table 5.

3.3. Scenario 3: Leaving of an Existing Node. When a nodeleaves the network, all the keys which are shared with thatparticular node are refreshed. Moreover, the media mixingalgorithm removes the entry of the leaving node from “Sendto/Receive from” list of all the other nodes. In Table 6, nodeD leaves the network, all the keys shared with node D arerefreshed immediately and the entry of D is removed fromthe list of all the existing nodes. Total numbers of keys sharedwith some nodes are also decreased.

4. Results and Discussion

To validate the results and performance of the proposedmedia mixing algorithm, we simulate it using the NS3.In the first set of experiments, we compared our solutionwith existing broadcast schemes on the basis of reliability,performance, privacy, relevancy, and redundancy. Results ofother techniques are obtained from the literature [23]. Resultsare summarized in Table 7.

In the best technique, reliability, privacy, and relevancyshould be high and redundancy should be very low. Themobility model we use is Manhattanmobility model [24] andgeneric mobility simulation framework generates the traffic.We find that our solution provides better results in eachof the above-mentioned performance criteria as comparedto existing broadcast techniques. Simple flooding is highlyreliable because a message can reach destination throughmany different routes. Performance is moderate and conges-tion is very high in simple flooding due to transmission ofevery packet to all the neighbors. Since message is deliveredthrough blind broadcasting, privacy cannot be achieved andrelevancy cannot be considered in case of simple flooding.Message can reach destination through different routes soredundancy is also very high in simple flooding.

Probabilistic scheme reduces the collision, contention,and redundant messages in dense network as it broadcaststhe messages with some fixed probability. But, in sparsenetwork, all the vehicles cannot receive the same packetswith small probability. If the probability is increased, itworks much like flooding. Hence, its performance becomesgreater in dense network as compared to sparse network.Counter base scheme reduces the redundancy while givingthe performance similar to probabilistic scheme.

Distance based and location based approaches are themoderate approacheswhile the neighbor knowledgemethodscompromise on privacy and are moderate in redundancy.Tree based approach again compromises on privacy whilerelevancy is also moderate in this approach. UMB andMDDV are average not suitable approaches in terms ofprivacy and relevancy. Relevance based approach is amongthe better approaches but privacy and reliability aremoderatein this approach. MHVB compromises over privacy whileadaptive broadcast protocol is redundant and not suitable interms of privacy. Our proposed approach is highly reliablebecause of the extra information attached with the packet.Performance is also very high as key refreshment load is


Table 5: Group IDs and session keys for each node after joining of a new node.

User Group ID Send to Receive from Session keysA 1 C, D, F B, C, D, E, G, Q, S 1 + 7B 2 A, C, P C, P, S, Z 1 + 4C 3 A, B, D, P, S A, B, D, F, G, Q, P, S, Z 1 + 9D 4 A, C, F, G, Q, P A, C, F, S, Z 1 + 5E 5 A, G G 1 + 1F 6 C, D, G A, D, G, Q 1 + 4G 7 A, C, E, F, P, S E, F, Q, P, S 1 + 5Q 8 A, C, F, G, P, S D 1 + 1P 9 B, C, G B, C, D, G, Q, Z 1 + 6S 10 A, B, C, D, E, G C, G, Q 1 + 3Z 11 B, C, D, P D, S 1 + 2

Table 6: Send to/receive from list and keys information after a node leaves the network.

User Send to Receive from Session keysA C, F, P, S B, C, E, G, Q, S 1 + 6B A, C, P, S C, P, S, Z 1 + 4C A, B, F, P, S A, B, F, G, Q, P, S, Z 1 + 8D A, B, C, E, F, G, Q, P, S A, C, F, S, Z 1 + 5E A, B, G, P, S G 1 + 1F B, C, G, Q A, G, Q 1 + 3G A, B, C, E, F, Q, P, S E, F, Q, P, S 1 + 5Q A, B, C, E, F, G, P, S 1P B, C, F, G B, C, G, Q, Z 1 + 5S A, B, C, E, F, G, Q, P C, G, Q 1 + 3Z B, C, P S 1 + 1

reduced and message is also delivered only to relevant nodes.Privacy is achieved by sharing the key only between thosenodes which really want to communicate with each other.Since each user specifies that from whom he/she wants toreceive and to whom he/she wants to send so the solutionprovides high level of relevancy. Message ID and group IDjointly control the redundancy of messages in our proposedsolution so redundancy is very low in our solution.

In the next set of experiments we take total 10 nodes andwe measured how many nodes need a refreshed key aftercertain period of time. We set an environment in which anode leaves the network after every 60 seconds and withinthese 60 seconds one new node also joins the network. Wefind that after 600 seconds total 200 nodes refreshed theirkeys, those have already joined the networkwithout leaving it,in simple broadcast scheme. We repeat the same experimentby implementing our media mixing technique and we findthat total 93 nodes refreshed their keys within 600 seconds.Results are shown in Figure 2.

In the second set of experiments, we measured theaverage number of messages received by every node withinthe network. As per Figure 3, we used 10 nodes to test thescenario and the results were measured by sending differentnumber of messages. When every node of the network sends50 messages, the average number of messages received by asingle node is 450 in simple broadcast technique while it is

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Figure 2: Total number of nodes that need key refreshment.

260 in media mixing based broadcast. In simple broadcastscheme 190 extramessages are delivered to every node withinthe network that consume considerable wastage of resourcesat receiver’s end because these messages are not relevant tothat particular users and categorized as unwanted messages.


Table 7: Comparison of media mixing algorithms with existing broadcast approaches.

Protocols Reliability Performance Privacy Relevancy RedundancySimple flooding Very high Moderate Very low Very low Very highProbabilistic scheme Moderate Moderate Low Moderate ModerateCounter based scheme Moderate Moderate Very low Low LowDistance based approach Moderate Moderate Moderate Moderate ModerateLocation based approach Moderate Moderate Very low Moderate ModerateNeighbor knowledge method High High Very low High ModerateTree based broadcast High High Very low Moderate LowUMB High High Very low Low ModerateMDDV High High Very low Very low LowRelevance based approach Moderate High Moderate High LowMHVB High High Very low Moderate LowAdaptive broadcast protocol High High Very low Moderate HighMedia mixing algorithm (proposed) High High High High Very low

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Figure 3: Average number of messages received by each user.

So on one hand these messages create disturbance for thereceiver and on the other hand these consume resources.

In last set of experiments, we measured that how fre-quently a node needs a refreshed key. 600 seconds are set asmaximum life time of a key. After that, we tested the averagetime by changing the joining and leaving rate of vehicles.When 10 nodes leave and the other 10 nodes join the networkwithin an hour, we find that the key needs to be refreshedafter every 183 seconds in simple broadcast while after every319 seconds inmediamixing based broadcast.When 50nodesper hour are joining and leaving the network, the key needsto be refreshed after every 41 seconds in simple broadcastwhile after every 54 seconds inmediamixing based broadcasttechnique. So we can conclude that in media mixing basedbroadcast keys are refreshed less frequently (with respectto maximum life time of the key) as compared to simple

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Figure 4: Average lifetime of a key.

broadcast techniques. Figure 4 shows the above mentionedresults.

5. Conclusion

In VANETs, nodes are leaving and joining the network veryfrequently so it is not preferred to use unicast based protocols.Due to its dynamic topology, broadcast is always preferredin VANETs. Simple broadcasting creates different types ofproblems including privacy, disturbance, and resource uti-lization problems. In this paper, we proposed a media mixingalgorithm for VANETs that solves these problems and utilizesthe cryptographic keys efficiently. Rules are specified by everynode and after that a media mixing algorithm is applied onthe specified rules and a final list of rules is determined.Keys are distributed on the basis of groups formulatedthrough media mixing algorithm. We have conducted allthe experiments by taking lesser number of nodes but by


increasing the number of nodes results may change a bit. Infuture it is planned to test the solution for more dense andpopulated network scenarios.

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper.

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