Optimized-Eight-State CV-QKD Protocol Outperforming Gaussian Modulation Based Protocols

Abstract

In this paper, an optimized-eight-state CV-QKD protocol is proposed significantly outperforming previously introduced discrete modulation (DM) protocols as well as the corresponding Gaussian modulation (GM)-based CV-QKD protocols for practical reconciliation efficiencies values in terms of both secret-key rate (SKR) and achievable distance. The proposed CV-QKD protocol also outperforms, in terms of SKR, the corresponding high-cost single-photon DV-QKD scheme, employing an array of multiplexed single-photon detectors, for several orders of magnitude. We also describe a generalized RF-assisted CV-QKD scheme with heterodyne detection applicable to arbitrary DM scheme, insensitive to the laser phase noise and frequency offset fluctuations.

On the Photon Subtraction-Based Measurement-Device-Independent CV-QKD Protocols

“…In opt8QAM four points are placed on circle of radius 1, while four points on circle of radius r. The maximization of SKR is performed with respect to the radius of outer circle and variances of the sources. For additional details related to the opt8QAM an interested reader is referred to our previous publication [35]. In all theoretical calculations, based on previous two sections [in particular Eqs.…”

“…where Z DM is the correlation parameter dependent on DM scheme. As an illustration, Z DM for 8PSK can be calculated as described in [17], while for optimized 8QAM the Z DM parameter is determined in [35].…”

“…In this paper, we study our previously proposed optimized eight-state DM protocol [35], called here optimized-8QAM, in MDI and virtual photon subtraction-based MDI CV-QKD settings. We demonstrate in Section V that the optimized eight-state MDI protocol can significantly outperform corresponding Gaussian modulation-based MDI and virtual photon subtraction-based MDI CV-QKD protocols in terms of both secret-key rate and achievable transmission distance.…”

An Improved Slice Reconciliation Protocol for Continuous-Variable Quantum Key Distribution

“…Quantum key distribution (QKD), which enables two remote legitimate parties (i.e., Alice and Bob) to share unconditional secret keys against a potential eavesdropper, is a major practical quantum cryptography technology in quantum information [1]. There are mainly two categories of QKD protocols, namely discrete-variable (DV) protocols [2][3][4][5][6] and continuous-variable (CV) protocols [7][8][9][10][11], which, respectively, encode information on discrete variables (such as the polarization or the phase of single photons) and continuous variables (such as the quadratures of coherent states).…”

On Global Quantum Communication Networking

“…Unfortunately, the security proofs of DM-based CV-QKD schemes for collective and coherent attacks are still incomplete. To overcome key challenges for DV-QKD, such as low SKR values and limited distance, as well as for DM-based CV-QKD, such as incompleteness of security proofs, the following approaches have been proposed in our recent papers: (1) discretized GM (DGM)-CV-QKD [ 11 ], (2) optimized CV-QKD [ 12 ], and (3) hybrid DV-CV QKD [ 13 ]. An alternative approach to QKD is post-quantum cryptography (PQC) [ 14 ].…”