Secret Key Generation With Multiantenna Relays

Abstract

One effective way of generating and distributing secret keys for secure communication is to exploit the randomness of wireless channels. Since a potential eavesdropper has a different propagation channel than two legitimate users, it can be used to generate unique and secure keys. If the two devices are far apart, a relay can aid the process. This paper presents a novel precoding scheme for the relay which delivers the keys directly and with very little processing required at the end devices. We also compare scalar and vector quantisation and show that a tree-based vector quantisation scheme has better performance than the former but much lower complexity than the latter.INDEX TERMS Physical layer security, secret key generation, relay.