Secure and efficient decoy-state quantum key distribution with inexact pulse intensities

TL;DR

This paper introduces a robust decoy-state quantum key distribution protocol that remains secure and efficient despite large random errors in pulse intensities, by utilizing a new theorem for verifying single-photon transmittance.

Contribution

It provides a general theorem for efficient verification of single-photon transmittance lower bounds and demonstrates unconditional security under inexact pulse intensities.

Findings

Linear terms of fluctuation vanish, quadratic terms dominate

Protocol remains secure with arbitrary intensity errors

Efficient key distribution despite large random intensity errors

Abstract

We present a general theorem for the efficient verification of the lower bound of single-photon transmittance. We show how to do decoy-state quantum key distribution efficiently with large random errors in the intensity control. In our protocol, the linear terms of fluctuation disappear and only the quadratic terms take effect. We then show the unconditional security of decoy-state method with whatever error pattern in intensities of decoy pulses and signal pulses provided that the intensity of each decoy pulse is less than $\mu$ and the intensity of each signal pulse is larger than $\mu'$.