Decorrelating Secret Bit Extraction Via Channel Hopping in Body Area Networks
Recent research has demonstrated that two communicating parties can generate shared secret keys by exploiting characteristics of the wireless fading channel between them. These channel characteristics are symmetric, dependent on position and orientation, highly sensitive to motion, and cannot be deduced in detail by an eavesdropper. One problem with this approach, however, is that over small channel sampling intervals, successively sampled values are correlated in time, which therefore yields keys with reduced entropy. In this paper, the authors undertake experiments to determine the efficacy of using channel hopping to increase diversity and improve secret key entropy, in the context of body area networks.