Decoy-state quantum key distribution with biased basis choice

TL;DR

This paper introduces a simplified decoy-state quantum key distribution scheme with biased basis choice, significantly increasing key rates and reducing system complexity by optimizing basis selection and applying rigorous phase error rate bounds.

Contribution

It presents a novel QKD protocol combining biased basis choice with decoy states, enhancing efficiency and key rate compared to standard methods.

Findings

Key rate increased by at least 45% in simulations.

Scheme reduces random number consumption and system complexity.

Rigorous phase error rate bounds improve security analysis.

Abstract

We propose a quantum key distribution scheme that combines a biased basis choice with the decoy-state method. In this scheme, Alice sends all signal states in the $Z$ basis and decoy states in the $X$ and $Z$ basis with certain probabilities, and Bob measures received pulses with optimal basis choice. This scheme simplifies the system and reduces the random number consumption. From the simulation result taking into account of statistical fluctuations, we find that in a typical experimental setup, the proposed scheme can increase the key rate by at least 45% comparing to the standard decoy-state scheme. In the postprocessing, we also apply a rigorous method to upper bound the phase error rate of the single-photon components of signal states.