We propose a new quantum key distribution (QKD) protocol based on the fully quantum mechanical states of the Faraday rotators. The protocol is unconditionally secure against collective attacks for multi-photon source 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.
@article{arxiv.quant-ph/0612208,
title = {Quantum Key Distribution Using Quantum Faraday Rotators},
author = {Taeseung Choi and Mahn-Soo Choi},
journal= {arXiv preprint arXiv:quant-ph/0612208},
year = {2008}
}