Key establishment protocols using environmental and physiological data in wireless sensor networks

Abstract

Wireless sensor networks provide solutions to a range of monitoring problems. However, they also introduce a new set of challenges mainly due to small memories, weak processors, limited energy and small packet size. Thus only a very few conventional protocols can readily be used in sensor networks. Sensor networks can exist in many different environments, and each environment has its own unique characteristics and requirements. As an example application, body sensor network is examined in detail in this paper. It is used as the basis for the requirements for the proposed key establishment protocols. This paper proposes four protocols that sensors can use to derive keys from cryptographically weak environmental data, which is normally found in body sensor networks. We also develop an innovative key establishment protocol, which can be used when each sensor measures different environmental data. This is achieved without the necessity of using traditional encryption. We map the applicability of each protocol to the corresponding characteristics found in different types of environmental data. Detailed analysis of each of the protocols is provided. The protocols were implemented in TinyOS and simulated using TOSSIM. Energy consumption and memory requirements are analysed and found that an RSA implementation of our protocols has some advantages over an ECC implementation.