Security analysis of decoy state quantum key distribution incorporating finite statistics

TL;DR

This paper improves the security analysis of decoy state quantum key distribution by deriving finite-length bounds on eavesdropper's information, addressing practical statistical fluctuations in real-world implementations.

Contribution

It introduces a finite code length security analysis for decoy state QKD with multiple decoy intensities, surpassing previous asymptotic approaches.

Findings

Derived upper bounds on eavesdropper's information for finite-length QKD

Numerical simulations show optimized parameters improve security

Addresses finite statistics effects in practical QKD implementations

Abstract

Decoy state method quantum key distribution (QKD) is one of the promising practical solutions to BB84 QKD with coherent light pulses. In the real world, however, statistical fluctuations with the finite code length cannot be negligible, and the securities of theoretical and experimental researches of the decoy method state QKD so far are based on the asymptotic GLLP's formula which guarantees only that the limit of eavesdropper's information becomes zero as the code length approaches infinity. In this paper, we propose a substantially improved decoy state QKD in the framework of the finite code length and derive the upper bound of eavesdropper's information in the finite code length decoy state QKD with arbitrary number of decoy states of different intensities incorporating the finite statistics. We also show the performance of our decoy QKD and optimal values of parameters by numerical simulation.