Impact of direct-path wave on Imac in secret key agreement system using ESPAR antennas

Current cryptography may be potentially decrypted by an extremely high performance computer. More secure key sharing schemes are expected. One possible solution is secret key agreement system which makes use of Electrically Steerable Parasitic Array Radiator (ESPAR) antenna. In this scheme ideally, by using wave propagation characteristics, eavesdropper cannot guess secret key from regular terminals. Actually however, eavesdropper has chances to guess the key if he is located on the line of direct-path wave between regular terminals. In our study, we evaluate the impact of direct-path wave on Information mutual anti-tapping condition (Imac) under a noisy channel.