  With the expansion of wireless sensor networks (WSNs), the need for securing
the data flow through these networks is increasing. These sensor networks allow
for easy-to-apply and flexible installations which have enabled them to be used
for numerous applications. Due to these properties, they face distinct
information security threats. Security of the data flowing through across
networks provides the researchers with an interesting and intriguing potential
for research. Design of these networks to ensure the protection of data faces
the constraints of limited power and processing resources. We provide the
basics of wireless sensor network security to help the researchers and
engineers in better understanding of this applications field. In this chapter,
we will provide the basics of information security with special emphasis on
WSNs. The chapter will also give an overview of the information security
requirements in these networks. Threats to the security of data in WSNs and
some of their counter measures are also presented.
