Wireless Sensor Networks: An Overview on Security Issues and Challenges

*Corresponding Author: Arundhati Nelli, Email: arundhati.nelli007@gmail.com
REVIEW ARTICLE
www.ajcse.info
Asian Journal of Computer Science Engineering2016; 1(2):29-34
Wireless Sensor Networks: An Overview on Security Issues and Challenges
*Arundhati Nelli1
, Sushant Mangasuli2
1,2
Visvesvaraya Technological University BELGAUM
Received on: 20/10/2016, Revised on: 14/11/2016, Accepted on: 01/12/2016
ABSTRACT
Wireless Sensor Networks (WSNs) are formed by deploying as large number of sensor nodes in an area
for the surveillance of generally remote locations. A typical sensor node is made up of different
components to perform the task of sensing, processing and transmitting data. WSNs are used for many
applications in diverse forms from indoor deployment to outdoor deployment. The basic requirement of
every application is to use the secured network. Providing security to the sensor network is a very
challenging issue along with saving its energy. Many security threats may affect the functioning of these
networks. WSNs must be secured to keep an attacker from hindering the delivery of sensor information
and from forging sensor information as these networks are build for remote surveillance and unauthorized
changes in the sensed data may lead to wrong information to the decision makers. This paper gives brief
description about various security issues and security threats in WSNs.
Keywords: Sensor, Security, Threats, wireless, overview, Challenges.
INTRODUCTION
Wireless Sensor Networks (WSN) are emerging
as both an important new tier in the IT ecosystem
and a rich domain of active research involving
hardware and system design, networking,
distributed algorithms, programming models, data
management, security and social factors . The
basic idea of sensor network is to disperse tiny
sensing devices; which are capable of sensing
some changes of incidents/parameters and
communicating with other devices, over a specific
geographic area for some specific purposes like
target tracking, surveillance, environmental
monitoring etc. Wireless Sensor Networks
(WSNs) are the collectors of information from the
physical world in the form of sensed data
according to the requirement like temperature,
pressure, humidity, level, movement etc. This data
is available to the sink through gateway. Sensors
are deployed in extensive numbers and on account
of its wireless nature; it is easily works in any type
of environment. Although sensor nodes are
deployed in a random manner still it’s important
to deploy them carefully. Deploying few nodes
may raise the issue of coverage and deploying too
many nodes may result in an inefficient network
because of more collision and interference.
Wireless Sensor Networks (WSNs) need effective
security mechanisms because these networks
deployed in hostel unattended environments. Due
to inherent limitations in wireless sensor
networks, security is a crucial issue. While
research in WSN security is progressing at
tremendous pace, no comprehensive document
lists the security issues and the threat models
which pose unique threats to the wireless sensor
networks.
We identify the security threats, review proposed
security mechanisms for wireless sensor networks.
Security in the Wireless Sensor Networks has
various difficulties, some common are:
dynamically changing topology, wireless
communication among the sensor nodes,
infrastructure-less framework, and limited
physical resources like energy source, memory
capacity and very low communication bandwidth .
Numerous analysts proposed so many threats
handling models and diverse security protocols for
secure data communication and routing in WSN.
Fig 1: Architecture for WSN

Nelli Arundhati et al. Wireless Sensor Networks: An Overview on Security Issues and Challenges
30
© 2015, AJCSE. All Rights Reserved.
There are many parameters affect selecting the
security mechanism as its speed and energy
consumption. The intent of this paper is to
investigate the security related issues and
challenges in wireless sensor networks.
WSN SECURITY REQUIREMENTS
A WSN is a sensor node has the limited
processing capacity, a limited storage capacity and
limited communication bandwidth, limited energy
and hardware size. There are so many types of
the sensor nodes currently available on different
platforms. The security also matter with the
design of the hardware of sensor nodes in the real
life. Sensor network have to fulfill some
requirements for providing a secure
communication. General security requirements of
WSNs are availability, confidentiality, integrity
and authentication. Some other requirements
known as secondary requirements are source
localization, self organization and data freshness.
These requirements gives protection against
attacks to the information transmitted over the
sensor network.
Data Confidentiality: In sensor network, data
flows from many intermediate nodes and chance
of data leak is more. To provide the data
confidentiality, an encrypted data is used so that
only recipient decrypts the data to its original
form.
Data Integrity: Data received by the receiver
should not be altered or modified is Data Integrity.
Original data is changed by intruder or due to
harsh environment. The intruder may change the
data according to its need and sends this new data
to the receiver.
Data Authentication: It is the procedure of
confirmation that the communicating node is the
one that it claims to be. It is important for receiver
node to do verification that the data is received
from an authenticate node.
Data Availability: Data Availability means that
the services are available all the time even in case
of some attacks such as Denial of service.
Source Localization: For data transmission some
applications use location information of the sink
node. It is important to give security to the
location information. Non-secured data can be
controlled by the malicious node by sending false
signal strengths or replaying signals.
Self-Organization: In WSN no fixed
infrastructure exists, hence, every node is
independent having properties of adaptation to the
different situations and maintains self organizing
and self healing properties. This is a great
challenge for security in WSN.
Data Freshness: Data freshness means that each
message transmitted over the channel is new and
fresh. It guarantees that the old messages cannot
be replayed by any node. This can be solved by
adding some time related counter to check the
freshness of the data.
Scalability: It should sustain a big number of
nodes.
Time Synchronization: It should avoid collision
and traffic manipulation.
OBSTACLES AND CONSTRAINTS
WSN is a wireless network which has several
constraints as compared to other similar networks.
These obstacles and restrictions make it complex
to implement security techniques in WSNs.
Therefore, to develop efficient security
mechanisms it is necessary to know and
comprehend and these obstacles, which are as
follows:
Limited Resources: The scarcity of resources
makes implementation of security techniques
difficult as they need a certain amount of
resources for operations e.g. data memory and
processing power.
Unreliable Communication: The security of the
network greatly depends upon the defined
protocols and communication medium which is
wireless in nature.
Unattended Operation: The sensor nodes may
be left unattended for long periods of time as per
the type of application of the particular WSN
which make them more vulnerable to many
attacks.
Due to these obstacles, the nodes and the network
experience many constraints which further effect
their overall functioning. For nodes the constraints
are limited energy, memory, storage space and
processing power. On the other hand due to these
obstacles the network becomes untrusted and
unreliable, collision prone and managed remotely
with no or less resiliency.
CATEGORIES OF ATTACKS IN WSNs
The attacks those are effective in WSNs can be
categorized by interruption and communication
act in three categories:
1. Outsider Vs Insider attacks: In this
WSN, outsider attacks may be known as
external attacks and the insider attacks
known as the internal attacks. An outsider
attacks come from outside the WSN. With
the help of Outsider attack the garbage
data is injected in network for the services
AJCSE,
Nov-Dec,
2016,
Vol.
1,
Issue
2

31
interruption if network and a DoS attack
is also rise. An insider attack is also
known as the internal attack, these attacks
come from the inside of the WSN, those
attacks want to interrupt the running
process in network and also exploit the
network assets.
2. Passive Vs Active Attacks: Passive
attack is easier to realize and not difficult
to detect because it does not modify any
information during the interchanged
information. After analyzing the routing
information we can make a active
attack.In active attacks, an attacker has
the capability to remove or modify the
messages during the transmission on the
network.
3. Mote-class Vs laptop-class attacks : In
bit class assaults, an enemy assaults a
WSN by utilizing a couple of hubs with
comparative capacities to the system
hubs; in portable PC class assaults, a foe
can utilize all the more capable gadgets to
assault a WSN. These gadgets have more
noteworthy transmission reach, handling
force, and vitality saves than the system
hubs. In bit class assaults, an enemy
assaults a WSN by utilizing a couple of
hubs with comparable capacities as that of
system hubs. In portable workstation class
assaults, an enemy can utilize all the more
capable gadgets like tablets, thus on and
can do substantially more mischief to a
system than a malicious sensor hub.
ATTACKS IN WSNS AT DIFFERENT
LAYERS
1. PHYSICAL LAYER: “The first layer is
physical layer that is responsible for
frequency selection, carrier frequency
generation, signal detection, modulation,
and data encryption. As with any radio-
based medium, there exists the possibility
of jamming and interferences”.
2. Data Link Layer: The next layer is data
link layer that is in charge for the
multiplexing of data streams, data frame
detection, medium access, and error
control, and responsible for point to point
& point –to-multipoint relation in the
network.
3. Network and Routing Layer: The third
layer is network and routing layer provide
more effective routing the data from
“Node to node, node to sink, node to base
station and node to Cluster head & vice
versa.” Due to the broadcast method every
node works as a router.
4. Transport Layer: “The transport layer is
responsible for managing end-to-end
connections. In sensor network connection
this layer is responsible to the
communication. There are three possible
attacks in this layer, flooding,
resynchronization and false message
injected.
The attacks on different layers and their defense
are given in below table.
Layers Attack types Defense
Transport
Layer
Flooding
Desynchronization
False message injected
Client puzzles, Rate
limitation
authentication
Network and
Routing
Layer
Black holes Sinkholes
Sybil Information & selective
forwarding Wormhole
Authentication,
Monitoring,
Redundancy
verification, packet
leashes
by using geographic
and temporal
information.
Redundancy
Authorization,
monitoring
Egress Filtering and
authentication
Data Link
Layer
Jamming & Collision,
Exhaustion,
Unfairness
Error correcting
Rate-limit Small
frames
Physical
Layer
Jamming
Tempering
Speed Spectrum,
Priority
Messages
Temper –proofing,
hiding
SECURITY LEVELS
In this paper our overview report has concentrated
on different
parts of sending secure conventions by the late
analysts. Numerous specialists have proposed a
wide range of systems to give security in
imprompt remote systems. The use of these
strategies to sensor systems is promising, however
the likelihood of pernicious hubs coercing great
hubs and the trouble in recognizing hub
misconduct. All are valuable building pieces for
securing directing conventions in sensor systems.
To accomplish proficient key administration, a
few symmetric key based systems were proposed
previously. So that the study on symmetric key
cryptography, as of late, there are various studies
researching the execution of PKC (Public Key
AJCSE,
Nov-Dec,
2016,
Vol.
1,
Issue
2

32
Cryptography) in sensor networks. Security
Mechanism is at two levels these are high level
and low level mechanism.
1. High Level Security
i. SGM (Secure Group Management)
ii. ID (Intrusion Detection)
iii. SDA (Secure Data Aggregation)
2. Low Level Security
i. Robustness to Communication DoS
ii. Security Routing
iii. Resilience to Node Capture
iv. Key Establishment and trust setup
v. Security and Authentication
vi. Privacy
SECURITY PROTOCOLS IN SENSOR
NETWORKS
Cryptography is a basic technique to achieve the
security in a network. This establishes a secure
relationship between two end points. In this,
sender encrypts the original data and receiver
decrypts the received data to obtain an original
data. Different types of keys are used in the
process of cryptography. The various protocols
that are proposed by different authors for solving
the security issue in WSN are:
1. SPINs
SPIN (Sensor Protocols for Information
via Negotiation) protocol works in three
steps. First, a node advertises the ADV
packet containing the metadata. If the
received node is interested in the data then
it sends the request for data using REQ
packet. Finally, the advertiser node after
receiving request sends the DATA packet
to the requestor node. It performs best in
small size networks because of its
efficiency and high latency properties.
Typical SPIN consists of two secure
building blocks named as μTESLA (Timed
Efficient Stream Loss-tolerant
Authentication) and SNEP (Sensor
Network Encryption Protocol). SNEP
provides confidentiality, authentication
and integrity. It uses the concept of
encryption. To authenticate the data, MAC
(Message authentication Code) is used. It
adds 8 bytes to the message. To reduce the
communication overhead, SNEP uses a
shared counter between sender node and
receiver node. After each block counter
gets incremented. Counter helps in
identifying the freshness of data. In
TESLA, digital signatures are used to
authenticate the data packet. Sink node
computes a MAC on the packet after
receiving the packet with the secret key to
send an authenticated packet back to
source. After receiving a packet node
confirms that the sink does not disclose the
computed MAC key to other nodes. With
this, receiving node assures that data
packet is original and no alterations are
done in the packet.
2. LEAP
LEAP (Localized Encryption and
Authentication Protocol) is a protocol with
key management scheme that is very
efficient with its security mechanisms used
for large scale distributed sensor networks.
It generally supports for inside network
processing such as data aggregation. In-
network processing results in reduction of
the energy consumption in network. To
provide the confidentiality and
authentication to the data packet, LEAP
uses multiple keys mechanism. For each
node four keys are used known as
individual, pair wise, cluster and group
key. All are symmetric keys and use as
follows: Individual Key: It is the unique
key used for the communication between
source node and the sink node.
i. Pair wise Key: It is shared with
another sensor nodes.
ii. Cluster Key: It is used for locally
broadcast messages and shares it
between the node and all its
surrounding neighboring nodes.
iii. Group Key: globally shared key
used by the entire network Nodes.
These keys can also be used by
other non-secured protocols to
increase the network security.
LEAP is satisfies several security
and performance requirements of
WSN. LEAP is used to defend
against HELLO Floods Attack,
Sybil Attack and Wormhole
Attack.
3. TINYSEC
TINYSEC is link layer security
architecture for WSNs. It is a lightweight
protocol. It supports integrity,
confidentiality and authentication. To
achieve confidentiality, encryption is done
by using CBC (Cipher-block chaining)
mode with cipher text stealing, and
authentication is done using CBC-MAC.
No counters are used in TINYSEC. Hence,
AJCSE,
Nov-Dec,
2016,
Vol.
1,
Issue
2

33
it doesn’t check the data freshness.
Authorized senders and receivers share a
secret key to compute a MAC. TINYSEC
has two different security options. One is
for authenticated and encrypted messages
(TinySec-AE) and another is for
authenticated messages (TinySec-Auth). In
TinySec-AE, the data payload is encrypted
and the received data packet is
authenticated with a MAC. In TinySec-
Auth mode, the entire packet is
authenticated with a MAC, but on the
other hand the data payload is not
encrypted. In CBC, Initialization Vector
(IV) is used to achieve semantic security.
Some of the messages are same with only
little variation. In that case IV adds the
variation to the encrypted process. To
decrypt the message receiver must use the
IV. IV sare not secret and are included in
the same packet with the encrypted data.
4. ZIGBEE
ZIGBEE is a typical wireless
communication technology. It is used in
various applications such as military
security, home automation and
environment monitoring. IEEE 802.15.4 is
a standard used for ZIGBEE. It supports
data confidentiality and integrity. To
implement the security mechanism
ZIGBEE uses 128 bit keys. A trust center
is used in ZIGBEE which authenticates
and allows other devices/nodes to join the
network and also distribute the keys.
Generally, ZIGBEE coordinator performs
this function. Three different roles in
ZIGBEE are:
i. Trust Manager: It authenticates
the devices which are requesting to
join the network.
ii. Network Manager: It manages the
network keys and helps to maintain
and distribute the network keys.
iii. Configuration Manager: It
configures the security mechanism
and enables end-to-end security
between devices.
CHALLENGES
WSNs endure many restrictions like little
computation capability, limitedmemory, less
energy resources, propensity to physical capture,
and deficient of infrastructure, which make them
open to many security attacks or challenges and
make security techniques inevitable and desirable
with some security solutions. All the security
mechanisms discussed in the previous section
provide security to WSNs to a certain level only.
There are still remaining many issues and
challenges which need to be addressed and
resolved. It has been deduced that there are still
many issues remaining which need to be
addressed to make WSNs secure and efficient
like:
• Public Key cryptography methods require
excessive computation and storage in
resources constrained WSN.
• Most of the security techniques are
specific to certain attack which needs to be
flexible.
• Key distribution problem need to be
addressed to achieve encrypted and secure
communication.
• Key Updating is an open issue.
• Key Revocation is needs to be addressed
to prevent the malicious node from
participating in normal communication
The computational overhead need to be reduced in
resource constraint environment of WSN. The
scalability is also desired to make the WSNs
flexible for node addition and deletion.
CONCLUSION
Wireless Sensor Network has an great
significance in all aspects military and civilian but
it needs protection from all kinds security threats
and attacks. Today’s most of the offered security
mechanisms are based on definite network model
or specific attack as there is no such combined or
general model to make certain overall security. To
combine the different security techniques together
to work in collaboration with each other will lay
researchers open to a tough challenge. It will be
also important to notice the adaptability, cost-
effectiveness and energy efficiency to deploy such
schemes in different applications of WSNs.
REFERENCES
1. Jun Wu, Kaoru Ota, Mianxiong Dong,
Chunxiao Li, "A Hierarchical Security
Framework for Defending Against
Sophisticated Attacks on Wireless Sensor
Networks in Smart Cities", IEEE Access,
Vol. 4, pp. 416-424, 2016.
2. Agnihotri, Ram Bhushan, Ajay Vikram
Singh, and Shekhar Verma. "Challenges in
wireless sensor networks with different
performance metrics in routing protocols."
In Reliability, Infocom Technologies and
AJCSE,
Nov-Dec,
2016,
Vol.
1,
Issue
2

34
Optimization (ICRITO) (Trends and
Future Directions), 2015 4th International
Conference on, pp. 1- 5. IEEE, 2015.
3. Goutam Mali, Sudip Misra, "TRAST:
Trust-Based Distributed Topology
Management for Wireless Multimedia
Sensor Networks", IEEE Transactions on
Computers, Vol. 65, Issue: 6,pp. 1978-
1991, 2015.
4. Said O. Amara, R. Beghdad and Mourad
Oussalah, “Securing Wireless Sensor
networks: A survey”,Taylor & Francis, 04
feb 2013.
5. Akyildiz, I. F., Su, W.,
Sankarasubramaniam, Y, and Cayirci, E.,
“Wireless Sensor Networks: A Survey”,
Computer Networks, 38, 2002, pp. 393-
422.
6. Culler, D. E and Hong, W., “Wireless
Sensor Networks”, Communication of the
ACM, Vol. 47, No. 6, June 2004.
7. Dai, S, Jing, X, and Li, L, “Research and
analysis on routing protocols for wireless
sensor networks”, Proc. International
Conference on Communications, Circuits
and Systems, Volume 1, 27-30 May, 2005,
pp. 407-411.
8. Pathan, A-S. K., Islam, H. K., Sayeed, S.
A., Ahmed, F. and Hong, C. S., “A
Framework for Providing E-Services to the
Rural Areas using Wireless Ad Hoc and
Sensor Networks”, to appear in IEEE
ICNEWS 2006.
9. Xiangwu Gong, Hang Long, Feihong
Dong, Qing Yao, "Cooperative security
communications design with imperfect
channel state information in wireless
sensor networks", IET Wireless Sensor
Systems, Vol. 6, Issue: 2, pp. 35-41, 2016.
10. Y. Wang, G. Attebury, and B.
Ramamurthy, “A Survey of Security
Issues in Wireless Sensor Networks”,
IEEE Commun. Surveys Tutorials, vol. 8,
pp. 2–23, year 2006.
11. D. Estrin et al., “Instrumenting the World
with Wireless Sensor Networks,” Proc.
Int’l. Conf. Acoustics, Speech and Signal
Pro- cessing, Salt Lake City, UT, May
2001.
AJCSE,
Nov-Dec,
2016,
Vol.
1,
Issue
2

Wireless Sensor Networks: An Overview on Security Issues and Challenges

More Related Content

Similar to Wireless Sensor Networks: An Overview on Security Issues and Challenges(20)

More from BRNSSPublicationHubI(20)

Recently uploaded(20)

Wireless Sensor Networks: An Overview on Security Issues and Challenges