Quantum key distribution using quantum Faraday rotators

Abstract

We propose a new quantum key distribution (QKD) protocol based on the fully quantum mechanical states of Faraday rotators. The protocol is unconditionally secure against collective attacks for a multi-photon source of up to two photons on a noisy environment. It is also robust against impersonation attacks. The protocol may be implemented experimentally with the current spintronics technology on semiconductors.