19. Security in Sensor Networks

The rapid development of wireless technology in the last few years has created new interest in low-cost wireless sensor networks. Wireless sensor networks (WSNs) or just sensor networks are grids or networks made of spatially distributed autonomous but cooperating tiny devices called sensors, all of which have sensing capabilities that are used to detect, monitor, and track physical or environmental conditions, such as temperature, sound, vibration, pressure, motion, or pollutants, at different locations [1]. A sensor, similar to that in Fig. 19.1, is a small device that produces a measurable response to a change in a physical condition. Sensor nodes can be independently used to measure a physical quantity and to convert it into a signal that can be read by an observer or by an instrument [1]. The network may consist of just a few or thousands of tiny, mostly immobile, usually, randomly deployed nodes, covering a small or large geographical area. In many cases, sensor networks do not require predetermined positioning when they are randomly deployed, making them viable for inaccessible terrains where they can quickly self-organize and form a network on the fly.