Effectively Exploiting Parasitic Arrays for Secret Key Sharing

The extraction of a security key from the measure-ment of the wireless channel can be effectively achieved by meansof the use of parasitic antenna arrays; this kind of antenna canbe easily implemented in Wi-Fi hotspots or in vehicle-to-vehiclecommunications, providing a secure communication channel with-out previous key sharing between the terminals. In this paper,we discuss a methodology to correctly design the parasitic arrayand a practical method to share a binary key exploiting thevirtual channel provided by the parasitic elements. The proposedarchitecture presents very low complexity, because it requires onlyone transceiver for each terminal and cheap electronically con-trollable impedances, making this security technology particularlyattractive in low-cost applications.