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Secure And Efcient Data Transer For Hierarchical Based Wireless Sensor

Networks

CHAPTER 1

INTRODUCTION

A Network is defined as the group of people or systems or organizations who tend to

share their information collectively for their business purpose. In Computer terminology the

definition for networks is similar as a group of computers logically connected for the sharing

of information or services (like print services, multitasking, etc.!. Initially Computer

networks were started as a necessity for sharing files and printers but later this has moved

from that particular "ob of file and printer sharing to application sharing and business logic

sharing. #hese networks may be fi$ed (cabled, permanent! or temporary. A network can becharacterized as wired or wireless. %ireless can be distinguished from wired as no physical

connectivity between nodes are needed. #he wireless network can again further be classified

being mobile ad hoc networks and wireless sensor networks.

A %ireless &ensor Network (%&N! consists of spatially distributed autonomous

sensors connected via a (wireless! communications infrastructure to cooperatively monitor,

record and store physical or environmental conditions, such as temperature, sound, vibration,

pressure, motion or pollutants. A %ireless &ensor Network is a selfconfiguring network of

small sensor nodes communicating among themselves using radio signals, and deployed in

'uantity to sense, monitor and understand the physical world. %ireless &ensor nodes are

called motes. %&N provide a bridge between the real physical and virtual worlds. Allow the

ability to observe the previously unobservable at a fine resolution over large spatiotemporal

scales. ave a wide range of potential applications to industry, science, transportation, civil

infrastructure, and security.


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Fig 1.1 Wireless Sensor Network

%ireless sensor networks have seen tremendous advances and utilization in the past

two decades. &tarting from petroleum e$ploration, mining, weather and even battle

operations, all of these re'uire sensor applications. )ne reason behind the growing popularity

of wireless sensors is that they can work in remote areas without manual intervention. All the

user needs to do is to gather the data sent by the sensors, and with certain analysis e$tract

meaningful information from them. *sually sensor applications involve many sensors

deployed together. #hese sensors form a network and collaborate with each other to gather

data and send it to the base station. #he base station acts as the control centre where the data

from the sensors are gathered for further analysis and processing. In a nutshell, a wireless

sensor network (%&N! is a wireless network consisting of spatially distributed nodes whichuse sensors to monitor physical or environmental conditions. #hese nodes combine with

routers and gateways to create a %&N system. #here are several applications of wireless

sensor networks such as area monitoring, +nvironment+arth monitoring, forest fire detection

and natural disaster like tsunamis, volcanoes, health care, traffic control and home

automation.

&ome of the characteristics of wireless sensor networks are the, ability to withstand

bad environmental conditions, can deal with node failures, portable have dynamic network

topology, communicate failures their node heterogeneity, large scale of deployment,

unattended operation, capacity of a node is scalable, only limited by the bandwidth of a

gateway node. &ecure data transfer is most critical issue for %&N. -enerally, most of %&Ns

are deployed with rough, crude, deffered physical environment for military and healthcare

domain with trustless background. &o, securely data transmission is necessary and most

practical vision in %&N

.

&ecurity in sensor networks includes confidentiality, integrity and availability.

Confidentiality in %&Ns is accomplished by preventing outsiders from eavesdropping on

transmissions. #his is generally achieved by enciphering the relevant parts of a packet.

Integrity in general means that the receiver is assured that the network packet was not

tampered with or the message altered in some way. y ensuring the availability we mean that

the data is available in a timely fashion so that it is useful to the user. Availability in %&Ns is

of great concern to the user of the network. *nfortunately, many e$isting security primitives


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cannot be used in %&Ns, either because the computing power of the sensors is too limited or

the additional work created by the protocols causes e$cessive network traffic.

In a typical %&N, a large number of sensor nodes collect application specific

information from the environment and this information is transferred to a central base station

where it is processed, analyzed, and used by the application. In these resource constrained

networks, the general approach is to "ointly process the data generated by different sensors

while being forwarded toward the base station /01. &uch distributed innetwork processing of

data is generally called as data aggregation and involves combining the data that belong the

same phenomenon. #he main ob"ective of hierarchical data aggregation is to increase the

network lifetime by reducing the resource consumption of sensor nodes (such as battery

energy and bandwidth!. %hile increasing network lifetime, data aggregation protocols maydegrade the important 'uality of service metrics in wireless sensor networks, such as data

accuracy, latency, faulttolerance, and security. #herefore, the design of an efficient data

aggregation protocol is an inherently challenging task because the protocol designer must

tradeoff between energy efficiency, data accuracy, faulttolerance, latency, and security. In

order to achieve this trade off, data aggregation techni'ues are tightly coupled with how

packets are routed through the sensor network. ence, the architecture of the %&N plays a

vital role in the performance of different data aggregation protocols. #here are several

protocols that allow routing and aggregation of network packets simultaneously. #hese

protocols can be categorized into two parts2 clusterbased data aggregation protocols and tree

based data aggregation protocols. #o reduce the latency due to tree based data aggregation,

recent work on data aggregation process tends to group sensor nodes into clusters so that data

are aggregated in each group for improved efficiency.


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CHAPTER 2

CLASSIFICATION OF ROUTIN PROTOCOLS

3outing techni'ues are re'uired for sending data between sensor nodes and the base

stations for communication. 4ifferent routing protocols are proposed for wireless sensor

network. #hese protocols can be classified according to different parameters.

(a!3outing 5rotocols can be classified as 5roactive, 3eactive and ybrid, based on their

mode of functioning and type of target applications.

(b!3outing protocols can be classified as 4irect Communication, 6lat and Clustering

5rotocols, according to the 5articipation style of the Nodes.

(c!3outing 5rotocols can be classified as ierarchical, 4ata Centric and location based,

depending on the Network &tructure.

2.1 !ASED ON "ODE OF FUNCTIONIN AND T#PE OF

TARET APPLICATIONS

Pro$%ti&e'(

In a 5roactive 5rotocol the nodes switch on their sensors and transmitters, sense the

environment and transmit the data to a & through the predefined route.

+$amples2 #he 7ow +nergy Adaptive Clustering hierarchy protocol (7+AC! utilizes this

type of protocol.

Re$%ti&e'(

If there are sudden changes in the sensed attribute beyond some predetermined

threshold value, the nodes immediately react. #his type of protocol is used in time critical

applications.

+$amples2 #he #hreshold sensitive +nergy +fficient sensor Network (#++N! is an e$ample

of a reactive protocol.


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H)*ri+'(

ybrid protocols incorporate both proactive and reactive concepts. #hey first compute

all routes and then improve the routes at the time of routing.

+$amples2 Adaptive 5eriodic #++N(A5#++N! is an e$ample of a reactive protocol.

2.2 A%%or+ing to t,e P$rti%i-$tion st)le o t,e No+es

Dire%t Co//0ni%$tion'(

In this type of protocols, any node can send information to the ase &tation(&!

directly. %hen this is applied in a very large network, the energy of sensor nodes may be

drained 'uickly. Its scalability is very small.

+$amples2 &5IN is an e$ample of this type of protocol.

Fl$t'(

In this protocol, if any node needs to transmit data, it first searches for a valid route to

the & and then transmits the data. Nodes around the base station may drain their energy

'uickly. Its scalability is average.

+$amples2 3umor 3outing is an e$ample of this type of protocol.

Cl0stering Proto%ols'(

According to the clustering protocol, the total area is divided into numbers of clusters.

+ach and every cluster has a cluster head (C! and this cluster head directly communicates

with the &. All nodes in a cluster send their data to their corresponding C.

+$amples2 #++N is an e$ample of this type of protocol.

2. De-en+ing on t,e Network Str0%t0re

D$t$ Centri%'(

4ata centric protocols are 'uery based and they depend on the naming of the desired

data, thus it eliminates much redundant transmissions. #he & sends 'ueries to a certain area

for information and waits for reply from the nodes of that particular region. &ince data is

re'uested through 'ueries, attribute based naming is re'uired to specify the properties of the

data. 4epending on the 'uery, sensors collect a particular data from the area of interest and


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this particular information is only re'uired to transmit to the & and thus reducing the

number of transmissions.

+$amples2 &5IN was the first data centric protocol.

Hier$r%,i%$l'(

ierarchical routing is used to perform energy efficient routing, i.e., higher energy

nodes can be used to process and send the information8 low energy nodes are used to perform

the sensing in the area of interest.

+$amples2 7+AC, #++N, A5#++N.

Lo%$tion !$se+'(

7ocation based routing protocols need some location information of the sensor nodes.7ocation information can be obtained from -5& (-lobal 5ositioning &ystem! signals,

received radio signal strength, etc. *sing location information, an optimal path can be formed

without using flooding techni'ues.

+$amples2 -eographic and +nergyAware 3outing(-+A3!


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CHAPTER

SECURIT# CHALLENES IN WSN

#he nature of large, adhoc, wireless sensor networks presents significant challengesin designing security schemes. A wireless sensor network is a special network which has

many constraint compared to a traditional computer network.

Wireless "e+i0/

#he wireless medium is inherently less secure because its broadcast nature makes

eavesdropping simple. Any transmission can easily be intercepted, altered, or replayed by an

adversary. #he wireless medium allows an attacker to easily intercept valid packets and easily

in"ect malicious ones. Although this problem is not uni'ue to sensor networks, traditional

solutions must be adapted to efficiently e$ecute on sensor networks.

A+(Ho% De-lo)/ent

#he adhoc nature of sensor networks means no structure can be statically defined. Nodes

may be deployed by airdrop, so nothing is known of the topology prior to deployment. &ince

nodes may fail or be replaced the network must support self configuration. &ecurity schemes

must be able to operate within this dynamic environment.

Hostile En&iron/ent

#he ne$t challenging factor is the hostile environment in which sensor nodes function. 9otes

face the possibility of destruction or capture by attackers. #he highly hostile environment

represents a serious challenge for security researchers.

I//ense S%$le


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#he proposed scale of sensor networks poses a significant challenge for security mechanisms.

&imply networking tens to hundreds of thousands of nodes has proven to be a substantial

task.

Se%0rit) o$ls For Sensor Networks

#he security goals are classified as primary and secondary. #he primary goals are known as

&tandard security goals such as Confidentiality, Integrity, authentication and Availability

(CIAA!. #he secondary goals are 4ata 6reshness, &elf )rganization, #ime &ynchronization

and &ecure 7ocalization.

D$t$ Coni+enti$lit)'

Confidentiality is the ability to conceal messages from a passive attacker so that any

message communicated via the sensor network remains confidential. #his is the most

important issue in network security. A sensor node should not reveal its data to the neighbors.

D$t$ A0t,enti%$tion

Authentication ensures the reliability of the message by identifying its origin. An

adversary is not "ust limited to modifying the data packet. It can change the whole packet

stream by in"ecting additional packets. &o the receiver needs to ensure that the data used in

any decisionmaking process originates from the correct source. )n the other hand, when

constructing the sensor network, authentication is necessary for many administrative tasks

(e.g. network reprogramming or controlling sensor node duty cycle!. 6rom the above, we can

see that message authentication is important for many applications in sensor networks.

Informally, data authentication allows a receiver to verify that the data really is sent by the

claimed sender. In the case of twoparty communication, data authentication can be achieved

through a purely symmetric mechanism2 the sender and the receiver share a secret key to

compute the message authentication code (9AC! of all communicated data.

D$t$ Integrit)

4ata Integrity in sensor networks is needed to ensure the reliability of data and refers

to the ability to confirm that the message has not been tempered with, altered or changed.

+ven if the network has confidentiality measures there is still a possibility that the data

integrity has been compromised by alterations. #he integrity of the network will be in trouble

when2 A malicious node present in the network in"ects false data.

D$t$ A&$il$*ilit)


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Availability determines whether a node has the ability to use the resources and

whether the network is available for the messages to communicate. owever, failure of the

base station or cluster leader:s availability will eventually threaten the entire sensor network.

#hus availability is of primary importance for maintaining an operational network.

D$t$ Fres,ness'

+ven if 4ata Confidentiality and 4ata Integrity are assured, there is a need to ensure

the freshness of each message. Informally, data freshness suggests that the data is recent, and

it ensures that no old messages have been replayed. #o solve this problem a nonce or another

timerelated counter, can be added into the packet to ensure data freshness.

Sel Org$ni$tion'

A wireless sensor network is typically an adhoc network, which re'uires every sensor

node be independent and fle$ible enough to be selforganizing and selfhealing according to

different situations. #here is no fi$ed infrastructure available for the purpose of network

management in a sensor network. #his inherent feature brings a great challenge to wireless

sensor network security. If selforganization is lacking in a sensor network, the damage

resulting from an attack or even the risky environment may be devastating.

Ti/e S)n%,roni$tion

9ost sensor network applications rely on some form of time synchronization. &ensors

may wish to compute the end to end delay of a packet as it travels between two pair wise

sensors. A more collaborative sensor network may re'uire group synchronization for tracking

applications.

Se%0re Lo%$li$tion

)ften, the utility of a sensor network will rely on its ability to accurately

automatically locate each sensor in the network. A sensor network designed to locate faults

will need accurate location information in order to pin point the location of a fault.

*nfortunately, an attacker can easily manipulate nonsecured location information by

reporting false signal strengths, replaying signals.


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CHAPTER 3

APPLICATIONS OF WSN

Are$ /onitoring

Area monitoring is a common application of %&Ns. In area monitoring, the %&N is

deployed over a region where some phenomenon is to be monitored. A military e$ample is

the use of sensors detect enemy intrusion8 a civilian e$ample is the geofencing of gas or oil

pipelines.

He$lt, %$re /onitoring

#he medical applications can be of two types2 wearable and implanted. %earable

devices are used on the body surface of a human or "ust at close pro$imity of the user. #he

implantable medical devices are those that are inserted inside human body. #here are many

other applications too e.g. body position measurement and location of the person, overall

monitoring of ill patients in hospitals and at homes. odyarea networks can collect

information about an individual;s health, fitness, and energy e$penditure.

En&iron/ent$l4E$rt, sensing

#here are many applications in monitoring environmental parameters, e$amples of

which are given below. #hey share the e$tra challenges of harsh environments and reduced

power supply.

Air -oll0tion /onitoring

%ireless sensor networks have been deployed in several cities (&tockholm, 7ondon

and risbane! to monitor the concentration of dangerous gases for citizens. #hese can take

advantage of the ad hoc wireless links rather than wired installations, which also make them

more mobile for testing readings in different areas.

Forest ire +ete%tion


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A network of &ensor Nodes can be installed in a forest to detect when a fire has

started. #he nodes can be e'uipped with sensors to measure temperature, humidity and gases

which are produced by fire in the trees or vegetation. #he early detection is crucial for a

successful action of the firefighters8 thanks to %ireless &ensor Networks, the fire brigade willbe able to know when a fire is started and how it is spreading.

L$n+sli+e +ete%tion

A landslide detection system makes use of a wireless sensor network to detect the

slight movements of soil and changes in various parameters that may occur before or during a

landslide. #hrough the data gathered it may be possible to know the occurrence of landslides

long before it actually happens.

W$ter 50$lit) /onitoring

%ater 'uality monitoring involves analyzing water properties in dams, rivers, lakes ! 4ecryption2 4ata user decrypt the encrypted message with private key and verifies

receiving output is acceptable or not which depends on attribute matching.

Fig 3.3 Working !lo%k Di$gr$/ O T,e S)ste/


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Fig.3.6 Flow%,$rt For O-er$tion In SET(A!E

&+#A))& operates similar way to that of &+#A+. #he main goal in

onlineoffline setting is to allow precomputation of attribute based chipher te$t as possible

without knowing about cipher policy or attribute set.

&+#A))& implemented with five operations2 &etup, +$tract, )ffline +ncryption, )nline

+ncryption and 4ecryption.

?! &et up2 #his algorithm takes input as security parameters and set of attributes in system

and generates master key and public parameters.

! +$tract2 #his algorithm takes input as set of attribute and master key in order to generate

private key associated with set of attribute.

B! )ffline +ncryption2 #his algorithm takes parameter and generates output as intermediate

cipher te$t.


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>! )nline +ncryption2 #his algorithm takes input as public parameter, set of attribute and

intermediate cipher te$t and generate output as session key and cipher te$t.

0! 4ecryption2 this algorithm takes input as private key and cipher te$t in order to

decapsulate cipher te$t to get original message and to recover session key only if it satisfy

attribute constrain.

CONCLUSION

%ireless sensor network (%&N! is the network of hundreds and thousands of micro

sensor nodes, connecting each other by a wireless medium.%&N provide reliable sensing of

the environment, detecting and reporting events to the sink. #he main ob"ective of

hierarchical data aggregation is to increase the network lifetime by reducing the resource

consumption of sensor nodes.

In this scheme, design and developed two protocol scheme in order to get secure and

efficient data transfer over %&N, such as &+#A+ and &+#A))& based on Attribute

based encryption. As well as it provide security towards orphan node problem in secure data


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transmission. 4ue to use of hierarchical architecture provides balanced energy consumption

on every sensor node.

REFERENCES

/?1 %. einzelman, A. Chandrakasan, and . alakrishnan, An Application&pecific

5rotocol Architecture for %ireless 9icrosensor Networks,D I+++ #rans. %ireless Comm.,

vol. ?, no. >, pp. EEF EGF, )ct. FF.

/1 9an"eshwar, H.A. eng, and 4.5. Agrawal, An Analytical 9odel for Information

3etrieval in %ireless &ensor Networks *sing +nhanced A5#++N 5rotocol,D I+++ #rans.

5arallel < 4istributed &ystems, vol. ?B, no. ?, pp. ?JF?BF, 4ec. FF.

/B1 &. Ki et al.,D 5+AC2 5ower+fficient and Adaptive Clustering ierarchy 5rotocol for

%ireless &ensor Networks D Computer Comm., vol. BF, nos. ?>?0, pp. L>L0, FFG.


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/>1 Chengchi 7ee,5ei&han chung,and 9in&hiang wang Asurvey on Attributebased

+ncryption &cheme of Access Contol in Cloud +nvironmentD, International Mournal of

Network &ecurity, ol.?0,No.>,55.B?>F,MulyF?B.

/01 &usan ohenberger, rent %aters )nline)ffline Attributeased +ncryptionD,FFG.

/??1 &usan ohenberger, rent %aters Attributeased +ncryption with 6ast 4ecryptionD,L

may F?B.

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