Contribution estimation of dominant partial waves into phase of multipath signal used for encryption key generation

Abstract

Randomness of fast fading multipath channels has been used for encryption keys generation for a long time. It is believed that until an adversary is able to intercept all partial waves detected by legal users, generated keys are secure. In many cases, however, only one or two dominant waves may define the channel fading and generated key. In this work, we examine a possibility of creating a partial key highly-related to the legal key using information about only a few dominant partial waves. Based on simulation of multipath radio propagation, correlation of partial phase formed only by dominant waves and total phase of multipath signal is assessed for various contributions of the dominating component. A key interception probability is estimated for Multipath Key Generation systems exploiting randomness of carrier phase. An influence of the line-of-sight component and number of multipaths on the correlation of partial and total phases is considered.