Key Generation System Using Smart Antenna

Abstract

The technology of generating and sharing the key as the representative application of smart antennas is introduced. This scheme is based on the reciprocity theorem of radio wave propagation between the two communication parties. The random and intentional change of antenna directivity that is electrically changed by using such an ESPAR antenna as variable directional antenna is more effective for this scheme, because the propagation environment can be undulated intentionally and the reproducibility of the propagation environment can be decreased. In this chapter, experimental results carried out at many environments are described. From these results, this system has a potential to achieve the “unconditional security.”