Body Area Network Security: Robust Key Establishment Using Human Body Channel

In order for two sensors within a body area network to determine they are on the same body, e.g., for security purposes, extensive prior work considers the use of physiological values. We study the practicality of using body physiological values for securely exchanging messages for sharing keys. Due to its popularity in the literature, we use electrocardiography (ECG) signals, and show that cardiac physiology is incompatible with such schemes, due to the sensitivity to a node's deployment location on the body and the outsiders' capability to remotely sense the physiological value. As a solution for key sharing, we inject an artificial voltage signal to build a communication channel secure against an outsider. By implementing our scheme on a dead mouse and analyzing the human body channel characteristic with empirical data, we demonstrate the practicality of our scheme for body area network applications.