Tight Secure Key Rates for CV-QKD with 8PSK Modulation

Abstract

We use a recent numerical security proof approach to calculate tight secure key rates in the presence of collective attacks for a continuous-variable (CV) eight-state phase-shift keying (8PSK) protocol with heterodyne detection in the asymptotic limit. The results are compared to achievable secure key rates of a QPSK protocol obtained with the same security proof technique. Furthermore, we investigate the influence of radial postselection on the secure key rate and examine a recently suggested strategy to reduce the computational requirements on the error-correction phase for fourstate phase-shift-keying protocols. Based on our investigations, we suggest different strategies to reduce the raw key of 8PSK protocols significantly, only on the cost of a slightly lower secure key rate. This can be used to lower the computational effort of the error-correction phase, a known bottleneck in many practical implementations, considerably.

Neural network-based prediction of the secret-key rate of quantum key distribution

“…This allows QKD channels to be more effectively integrated into existing communication networks. In CV-QKD, discrete modulation technology has attracted much attention [26,[34][35][36][37][38][39][40][41][42][43][44] because of its ability to reduce the requirements for modulation devices. However, due to the lack of symmetry, the security proof of discrete modulation CV-QKD also mainly relies on numerical methods [37][38][39][40][41][42]45].Unfortunately, calculating a secure key rate by numerical methods requires minimizing a convex function over all eavesdropping attacks related with the experimental data [46,47].…”

“…In CV-QKD, discrete modulation technology has attracted much attention [26,[34][35][36][37][38][39][40][41][42][43][44] because of its ability to reduce the requirements for modulation devices. However, due to the lack of symmetry, the security proof of discrete modulation CV-QKD also mainly relies on numerical methods [37][38][39][40][41][42]45].…”