Source Location Privacy Using Ant Colony Optimization in Wireless Sensor Networks

Introduction

Wireless sensor networks (WSNs) are a network, which consists of large number of sensor nodes, which communicate through wireless links. Sensor nodes are basically small in size, low cost radio devices. They have limited processing capabilities and lifetime. WSNs enables several classes of application, such as disaster relief techniques, habitat monitoring and tracking, military surveillance, data collection, etc. One of the applications is subject tracking and monitoring applications, in which the monitored/tracked subject needs to be protected. As the sensor networks are generally deployed in an open environment so there is a maximum chance that the communication between the source node and the base station will be monitored by an attacker. A perfect example of the source location privacy is explained by Kamat et al. [6] in which a panda is monitored by some sensor nodes in the network. Each panda carries a tag which can be sensed by the surrounding sensor nodes in its communication range. Each sensor node receiving the tag signal from Panda creates data packets and deliver it to the sink node through wireless channel. An adversary monitoring the wireless channel can easily track the direction of incoming message and follow the route of incoming message . It may be possible that the adversary successfully trace the location of the panda and kill them. This situation demands some methods to hide the originator of the messages. Encryption techniques are not very helpful tool in this case as the adversary is not interested in the content of the message. He / She is only interested in finding the location of the creator of the message which can be traced by just back tracing the path, the message has followed to reach to the base station.

Privacy in wireless sensor networks is extensively researched issue and hence a number of protocols have been proposed to preserve the privacy and henceforth location privacy also. Source location privacy (SLP) is not possible only by securing the content of the message but it requires more than that. It also needs to hide the communication path of the message in the network so that if there is any adversary trying to reach to the real source of the message will not able to resolve the path of the message. Privacy in WSNs is basically categorized into two categories, named as (i) Content Privacy and (ii) Context Privacy. Figure 1 outlines the different types of privacy types considered in the wireless sensor network domain.

Figure 1.

Types of Privacy Wireless Sensor Network

Content privacy deals with securing the data content of a message. Different encryption/decryption techniques may be used to achieve data(content) privacy. However, context privacy deals with securing the contextual information like time of creation of the message, path of the message flow, the sender and receiver of the message and so on. It can be further categorized into locations and temporal privacy which hides the location of message and time of creation of message respectively. In this chapter, we are mainly concerned with the source location privacy in sensor network.

In this chapter, a new protocol called source location privacy for wireless sensor networks using ant colony optimization technique is proposed which is used to secure location of the source. When an ant start searching for the food, they have to visit the so many nodes in the networks and hence there are so many paths between the source point and the food point are created as shown in Figure 2.

Figure 2.

Random movement of an ant

Background

A comprehensive survey of various techniques used for source location privacy preservation in WSNs is compiled by Conti et al. (2013). They have classified various solutions of source location privacy in 11 different categories on the basis of core technique used for each solution. The categories are: