Finite-size analysis of a continuous-variable quantum key distribution

Abstract

The goal of this paper is to extend the framework of finite-size analysis recently developed for quantum key distribution to continuous-variable protocols. We do not solve this problem completely here, and we mainly consider the finite-size effects on the parameter estimation procedure. Despite the fact that some questions are left open, we are able to give an estimation of the secret key rate for protocols which do not contain a postselection procedure. As expected, these results are significantly more pessimistic than those obtained in the asymptotic regime. However, we show that recent continuous-variable protocols are able to provide fully secure secret keys in the finite-size scenario, over distances larger than 50 km.

Improving the maximum transmission distance of continuous-variable quantum key distribution using a noiseless amplifier

“…This latter condition is in particular met for all CV protocols without postselection for which Gaussian attacks are known to be optimal within collective attacks [8][9][10][11].…”

“…Alice and Bob finally extract a secret key from the correlated data by performing classical data processing and authenticated classical communication. This protocol offers a simple experimental implementation [3,[30][31][32] and is secure against finite-size collective attacks [33] as well as arbitrary attacks in the asymptotic limit of arbitrary long keys [7].…”

Continuous Variable Quantum Key Distribution with a Noisy Laser

“…If one disregards the problems that follow from finite key sizes [6,26,27], one arrives at a relatively simple bound on the secure key rate…”

Security of Continuous-Variable Quantum Key Distribution Against General Attacks

“…The generalization to modulation schemes with a higher number of states may be considered, but it is not so straightforward as one would lose the main advantage of the protocols presented here, that is, their very efficient reconciliation procedure. However, if one allows for a heterodyne detection instead of a homodyne detection, new continuous modulation schemes can lead to better performances [31].…”