Optimizing Continuous-Variable Quantum Key Distribution with Phase-Shift Keying Modulation and Postselection

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