By realizing a quantum cryptography system based on polarization entangled photon pairs we establish highly secure keys, because a single photon source is approximated and the inherent randomness of quantum measurements is exploited. We implement a novel key distribution scheme using Wigner's inequality to test the security of the quantum channel, and, alternatively, realize a variant of the BB84 protocol. Our system has two completely independent users separated by 360 m, and generates raw keys at rates of 400 - 800 bits/second with bit error rates arround 3 percent.
@article{arxiv.quant-ph/9912117,
title = {Quantum Cryptography with Entangled Photons},
author = {Thomas Jennewein and Christoph Simon and Gregor Weihs and Harald WeinfurterD and Anton Zeilinger},
journal= {arXiv preprint arXiv:quant-ph/9912117},
year = {2009}
}