Homodyne Detection Quadrature Phase Shift Keying Continuous-Variable Quantum key Distribution with High Excess Noise Tolerance

Discrete-modulated continuous-variable quantum key distribution with homodyne detection is widely recognized for its ease of implementation, efficiency respect to error correction, and compatibility modern optical communication devices. However, recent studies report that the application obtains poor tolerance excess noise insufficient transmission distance, hence seriously restricting large-scale deployment secure networks. In this paper, we propose a protocol using quadrature phase shift keying technique. By limiting information leakage, our proposed enhances high level. Furthermore, demonstrate performs better than heterodyne in quaternary-modulated under untrusted detector scenario. The security analyzed tight numerical method against collective attacks asymptotic regime. Our results imply current can distribute keys nearly intercity area and, thus, paves way constructing low-cost networks.3 MoreReceived 2 May 2021Revised 15 July 2021Accepted 21 October 2021DOI:https://doi.org/10.1103/PRXQuantum.2.040334Published by American Physical Society terms Creative Commons Attribution 4.0 International license. Further work must maintain attribution author(s) published article's title, journal citation, DOI.Published SocietyPhysics Subject Headings (PhySH)Research AreasQuantum communicationQuantum cryptographyQuantum networksQuantum opticsQuantum InformationAtomic, Molecular & Optical