The time-reversed version of entanglement-based quantum key distribution (QKD), called measurement-device-independent QKD (mdiQKD), was originally introduced to close arbitrary security loopholes of measurement devices. Here we show that the mdiQKD has another advantage which should be distinguished from the entanglement-based QKD. In particular, an all-photonic adaptive Bell measurement, based on the concept of quantum repeaters, can be installed solely in the mdiQKD, which leads to a square root improvement in the key rate. This Bell measurement also provides a similar improvement in the single-photon-based entanglement generation of quantum repeaters.
@article{arxiv.1408.2884,
title = {Measurement-device-independent quantum key distribution with all-photonic adaptive Bell measurement},
author = {Koji Azuma and Kiyoshi Tamaki and William J. Munro},
journal= {arXiv preprint arXiv:1408.2884},
year = {2014}
}