Hybrid Approach in Information-Hypothetically Furtive Solution Generation for Vanishing Wireless Channels

The multipath-rich wireless environment associated with typical wireless usage scenarios is characterized by a fading channel response that is time-varying, location-sensitive, and uniquely shared by a given transmitter-receiver pair. The complexity associated with a richly scattering environment implies that the shortterm fading process is inherently hard to predict and best modeled stochastically, with rapid decorrelation properties in space, time, and frequency. In this paper, we demonstrate how the channel state between a wireless transmitter and receiver can be used as the basis for building practical secret key generation protocols between two entities. We begin by presenting a scheme based on the "Reciprocity based key exchange model" allows two parties jointly establish physically secure key combined with a (standard) computationally secure key, over an insecure communication channel. This key can then be used to encrypt subsequent communications. The channel state between a wireless transmitter and receiver can be used as the basis for building practical secret key generation protocols between two entities. We validate both proposed protocols through experimentations using a customized 802.11a platform, and show for the typical Wi-Fi channel that reliable secret key establishment can be accomplished at rates on the order of 11 b/s.