International Journal of Engineering Trends and Technology (IJETT) – Volume 9 Number 7 - Mar 2014
A Survey on Location Privacy Protection of Source
and Sink Nodes in WSN
Dhivya.J1, Siddique Ibrahim.S.P2
1 – Student, Department of CSE, Kumaraguru College of Technology, Coimbatore-49
2 – Assistant Professor, Department of CSE, Kumaraguru College of Technology, Coimbatore-49
Tamil Nadu, India.
Abstract— Sensor networks are used to monitor objects in
variety of application. Privacy is one of the major issues of
wireless sensor network as the transmissions in the networks are
susceptible to illicit interception and detection. Many protocols
have been proposed that provide content-oriented security in
wireless sensor network but context oriented information
remains exposed. An adversary can utilize such context oriented
information and deduce sensitive information such as the
locations of monitored objects and data sinks in the network
field. There are number of techniques that can defeat the limited
adversary called local eavesdropper who can only observe
network traffic in a limited region. However, such techniques are
not suitable in the case of global eavesdropper. Because the
global eavesdropper are well equipped and hence can observe a
wide area of the network. In order to overcome this problem
certain techniques have been proposed.
security, but requires line of sight and is sensitive to
atmospheric conditions. Infrared needs no antenna but it is
limited in its broadcasting capacity. RF is the most easy to use
but it requires antenna.
Keywords— location privacy, privacy, sink privacy, source
privacy.
I. INTRODUCTION
A Wireless Sensor Network (WSN) consists of spatially
distributed autonomous sensors to monitor the physical world
which are capable to collect data automatically. Sensor
networks can be used for wide range of applications where it
is difficult or infeasible to set up wired networks.
The WSN is built of nodes from a few to several hundreds
or even thousands, where each node is connected to one or
several sensors. Each such sensor network node has typically
several parts:
 a radio transceiver with
an
internal antenna or
connection to an external antenna,
 a microcontroller,
 an electronic circuit for interfacing with the sensors
and an energy source,
 a battery or an embedded form of energy harvesting.
A. Components of Sensor Node
1)
Controller: The controller performs tasks, processes
data and controls the functionality of other components in the
sensor node.
2)
Transceiver:
There
are
three
deploying
communication schemes in sensors including optical
communication (laser), infrared, and Radio-Frequency (RF).
Laser consumes less energy than radio and provides high
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Fig.1 Architectue of sensor node
3)
External memory: Memory requirements are very
much application dependent. Two categories of memory based
on the purpose of storage,

User memory - used for storing application related or
personal data
 Program memory - used for programming the device.
Program memory also contains identification data of the
device if present.
4)
Power source: One of the most important
components of a sensor node is the power unit. Every sensor
node is equipped with a battery that supplies power to remain
in active mode. Power consumption is a major weakness of
sensor networks. Batteries used in sensors can be categorized
into two groups such as rechargeable and non-rechargeable.
5)
Sensors: The main functionality of the sensing unit is
to sense or measure physical data from the target area.
B. Characteristics of sensor network
The main characteristics of a WSN include:
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International Journal of Engineering Trends and Technology (IJETT) – Volume 9 Number 7 - Mar 2014
 Power consumption constrains for nodes using
batteries or energy harvesting
 Ability to cope with node failures
 Mobility of nodes
 Communication failures
 Heterogeneity of nodes
 Scalability to large scale of deployment
 Ability to withstand harsh environmental conditions
 Ease of use
Privacy is one of the major issues in wireless sensor
network and it can be categorized into two ways: contentoriented privacy and contextual privacy. Content-oriented
privacy is concerned with the ability of adversaries to learn
the content of transmitted in the network. The contents can be
protected using encryption algorithm. Contextual privacy
concerns with the ability of adversaries to deduce information
by observing the sensors and communications without access
to the content of messages. The adversary can extract the
location information about the source and sink nodes in the
network using the contextual information. Existing protocols
provide location privacy to such issues against the local
adversary.
II. REVIEW OF LOCATION PRIVACY PROTECTING
TECHNIQUES
The location privacy techniques can be classified into two
ways:
 Source-location privacy techniques
 Sink location privacy techniques
Various location privacy preserving techniques are
discussed as follows.
A. Baseline Flooding
In baseline flooding the source node transmits or broadcasts
message to each of its neighbours. These neighbours in turn
retransmit or rebroadcast the message to each of its
neighbours and so on. Thus packet is flooded from source to
destination through number of paths which make it difficult
for an adversary to trace the source.
A node can forward the packet only once. If a packet is
received again by a node, it discards the packet. The drawback
in this method is when an adversary can trace the node using
backtracking technique thus this method does not provide
much privacy but consumes significant amount of energy.
B. Phantom Flooding
In phantom routing, the packets are transmitted to the
destination in two steps:
1) the random walk, which may be a pure random walk
or a directed walk, directing the message to a
phantom source,
2) a subsequent flooding/single path routing stage
delivers the message to the sink.
In this algorithm different messages exhibits different path
which increases the safety period against local eavesdropper.
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The drawback is the latency increases because every message
is directed to a random location first.
C. Routing With Fake Messages
In routing with fake messages technique, whenever a
sender notifies the destination that it has real data to send,
some nodes are assigned as fake sources. These fake senders
should be away from the real source and approximately at the
same distance from the destination as the real source.
Both real and fake senders start generating packets at the
same time when the real data are to be transmitted. This
technique provides privacy against a local eavesdropper. But
this technique fails to protect the privacy against global
eavesdropper.
D. Periodic Collection
In periodic collection, each sensor node is assigned with a
timer and a FIFO queue. The timer starts once the nodes are
deployed. All sensor nodes transmit once the timer expires.
The nodes have to buffer packets in the queue till the expiry of
the timer. After the expiry of the timer, the node checks its
queue for the packet. If the queue has packet, it starts its
transmission. If there is no packet the node transmits dummy
packet.
Since the traffic pattern changes due to the presence of real
objects which can be easily identified by global eavesdropper
this method makes all nodes to start transmission at the same
time. This method provides optimal location privacy but
consumes energy.
E. Source Simulation
In source simulation, fake objects are placed in the
network and simulated to confuse the adversary. Whenever
traffic about the real objects are generated, the fake source
traffic are also generated. The fake source traffic is generated
by certain set of nodes.
A set of sensor node is selected and assigned token. These
nodes are called token and they have unique id. The tokens
will be passed within the nodes to simulate the behaviour of
real objects. Every token node generates the traffic as if the
real event was detected in order to confuse the adversary.
F. Sink Simulation
In sink simulation, fake sinks are established in the
network. The fake sinks are simulated within the
communication range of real sink. When an event is detected,
the source node must transmit the packet to the fake sinks in
the network. So the entire fake sinks will receive the report
about the event. Te fake sinks broadcasts the packet locally to
the real sink. So its must that the real sink should be in the
communication range of at least one of the fake sink
G. Backbone Flooding
In backbone flooding, backbone is created with a set of
sensor nodes. The backbone members are selected based on
their neighbour count. The nodes with large number of
neighbours are selected as the backbone members. Whenever
an event is detected, the data is transmitted to the backbone
member.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 9 Number 7 - Mar 2014
This backbone floods the packet to the entire network. The
packets about the event detected are sent to the backbone
alone and real sink can receive from the backbone member.
So the real sink must be in the communication range of at
least one of the backbone member.
H. Location Privacy Routing(LPR) protocol
In LPR each sensor divides its neighbours into two
different lists: closer list and further list. Once the list is
constructed, a node can select the next hop node from any of
the two lists. If the next hop is selected from closer list, then
energy efficiency will be greater and if it is selected from next
hop from the further list, privacy protection will be stronger.
The LPR can be combined with fake packet injection so that
the retrieval of traffic direction information by the adversary
can be minimized.
I. Cyclic Entrapment Method(CEM)
Cyclic Entrapment Method creates looping paths in the
sensor network at various places. Each node on a route will
check if there is a loop in its route to destination while routing
message from source to destination. If it has loop it is
activated by sending fake message. If an adversary is trying to
analyze and trace the path and ends up in a node which is
common to loop and real path, adversary has to decide the
path. The local adversary trace up the loop repeatedly if
wrong decision is taken which in turn increase the safety
period. When the length of the loop increases, energy
consumption and privacy will increase.
TABLE I
COMPARISON OF LOCATION PRIVACY TECHNIQUES
Privacy
Baseline
flooding
Phantom
flooding
Excellent
privacy
against
local
adversary
Overhead
Overhead
is high
Delay
Very
less
extra
delay
Delay
increase
Power
consumption
Extra power is
consumed
Source
simulation
Very less
overhead
Less compared
to baseline
flooding
Routing
with fake
messages
Excellent
privacy
against
global
adversary
Overhead
is high
No extra
delay
Extra power is
consumed
CEM
Excellent if
loop is
chosen
repeatedly
Very less
overhead
No extra
delay
Very less extra
power
consumption
Periodic
collection
Good but
excellent
Very less
overhead
No extra
delay
Very less extra
power is
Very less
overhead
No extra
delay
Very less extra
power is
consumed
Excellent
privacy for
sink node
No extra
overhead
Very
less
extra
delay
Very less extra
power is
consumed
Backbone
flooding
Excellent
privacy for
sink node
No extra
overhead
Very
less
extra
delay
Extra power is
consumed
III. CONCLUSION
The location privacy preserving techniques are thus discussed.
The protocols must be strong enough to provide location
privacy protection against any kind of adversaries. Certain
protocols fail to work against well equipped adversary.
Privacy protection against global eavesdropper can be
achieved for source and sink nodes using periodic collection,
source simulation and sink simulation, backbone flooding
respectively. These techniques provide advantages in various
aspects like privacy, communication cost and latency.
REFERENCES
[1]
[2]
[4]
[5]
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consumed
Sink
simulation
[3]
Excellent
privacy
against
local
adversary
when
combined
with source
simulation
against
global
adversary.
Excellent
privacy
against
global
adversary
C. Ozturk, Y. Zhang, and W. Trappe, “Source-Location Privacy in
Energy Constrained Sensor Network Routing,” Proc. Workshop
Security of Ad Hoc and Sensor Networks (SASN ’04), Oct. 2004.
K. Mehta, D. Liu, and M. Wright, “Location Privacy in Sensor
Networks against a Global Eavesdropper,” Proc. IEEE Int’l Conf.
Network Protocols (ICNP ’07), 2007.
K. Mehta, D. Liu, and M.Wright,” Protecting Location Privacy in
Sensor Networks against a Global Eavesdropper", Mobile Computing,
vol.11, no.2, pp.320-336, Feb. 2012.
P. Kamat, Y. Zhang, W. Trappe, and C. Ozturk, “Enhancing SourceLocation Privacy in Sensor Network Routing,” Proc. Int’l Conf.
Distributed Computing Systems (ICDCS ’05), June 2005.
Y. Jian, S. Chen, Z. Zhang, and L. Zhang, “Protecting ReceiverLocation Privacy in Wireless Sensor Networks,” Proc. IEEE
INFOCOM, pp. 1955-1963, May 2007.
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