A Private Key Sharing Scheme Based on Multipath Time Delay in UWB Systems

As a measure to prevent eavesdropping in UWB communication, this paper proposes a new method of private key sharing for UWB systems using impulse waves. Heretofore, schemes of private key sharing based on channel characteristics have been proposed for countermeasure against eavesdropper in radio communication systems using carrier modulation. However, it is generally difficult to apply the existing schemes to UWB systems where no carrier is used. In order to resolve the problem, a private key sharing scheme suitable for UWB systems was proposed. In the scheme, measurement accuracy of the arrival time difference decreases in the low SN ratio area. Therefore, in this paper, a new measurement method of the arrival time difference at both authorized radio station is proposed. Computer simulations are carried out to evaluate the performance of the proposed scheme in wireless PAN environments. The results of the computer simulations show that the proposed scheme can achieve 100% key agreement with the 3 bits error correction technique at signal-to-noise ratio of about 21 dB.