Efficient quantum key distribution with practical sources and detectors

TL;DR

This paper demonstrates that quantum key distribution systems using practical sources like attenuated lasers and threshold detectors can achieve unconditional security without sacrificing key rate or distance, by combining decoy states and security proofs based on the uncertainty principle.

Contribution

It introduces a method to ensure unconditional security in QKD with practical devices, overcoming previous limitations in key rate and distance.

Findings

Unconditional security achieved with practical devices

No significant penalty in key rate or distance

Decoy-state method enhances security in realistic QKD setups

Abstract

We consider the security of a system of quantum key distribution (QKD) using only practical devices. Currently, attenuated laser pulses are widely used and considered to be the most practical light source. For the receiver of photons, threshold (or on/off) photon detectors are almost the only choice. Combining the decoy-state idea and the security argument based on the uncertainty principle, we show that a QKD system composed of such practical devices can achieve the unconditional security without any significant penalty in the key rate and the distance limitation.