An Optimal Guard-Intervals Based Mechanism for Key Generation from Multipath Wireless Channels

Recently, multipath in wireless channels has shown an interesting aspect. It has been found that wireless channels may provide a common reciprocal source of randomness for any two communicating nodes. This seems particularly interesting for secret key generation in wireless networks. In this paper, we consider the randomness property of wireless channels and present an intelligent algorithm for key generation. We analyze the multipath channel and derive optimal parameters enabling efficient key extraction leveraging the richness of a wireless environment. Finally, we test our algorithm in a typical outdoor wireless channel. Our simulation results show that more than 70 secret bits can be extracted from a single channel observation.