Group-Based Cooperation on Symmetric Key Generation for Wireless Body Area Networks

Wireless body area networks (WBANs) require lightweight and resource efficient security approaches. In the literature, biometric-based security approaches have been well studied for WBANs when each individual person may have unique biometric features. However, additional sensing hardware (e.g., ECG sensors) are usually required for every sensor in these approaches, which make them unpractical in real application settings. Unlike them, in this paper, we propose a physical layer-based security approach utilizing physical channel information and remove the extra hardware requirements. Especially, a group-based cooperation on symmetric secret key generation via physical or link layer received signal strength indicator (RSSI) data accumulating is investigated. We propose a practical cooperative group solution to increase the similarity, fluctuation and density of RSSI data for high efficient key generation. The major innovation is to make full use of multiple channels between a participant node and a group or between two groups to randomly synthesize RSSI data with multifold data density and improved data similarity and fluctuation. In addition, several group models are described with the details of their specific protocol design. Furthermore, a prototype is implemented and verified in an experimental environment to demonstrate the high practicality and efficiency of our solution.