What is Data Freshness

In this chapter we present the growing challenges related to security in wireless sensor networks. We show possible attack scenarios and evidence the easiness of perpetrating several types of attacks due to the extreme resource limitations that wireless sensor networks are subjected to. Nevertheless, we show that security is a feasible goal in this resource-limited environment; to prove that security is possible we survey several proposed sensor network security protocols targeted to different layers in the protocol stack. The work surveyed in this chapter enable several protection mechanisms vs. well documented network attacks. Finally, we summarize the work that has been done in the area and present a series of ongoing challenges for future work.