Strengthening practical continuous-variable quantum key distribution systems against measurement angular error

Abstract

The optical phase shifter that constantly rotates the local oscillator phase is a necessity in continuous-variable quantum key distribution systems with heterodyne detection. In previous experimental implementations, the optical phase shifter is generally regarded as an ideal passive optical device that perfectly rotates the phase of the electromagnetic wave of $90^{\circ }$. However, the optical phase shifter in practice introduces imperfections, mainly the measurement angular error, which inevitably deteriorates the security of the practical systems. Here, we will give a concrete interpretation of measurement angular error in practical systems and the corresponding entanglement-based description. Subsequently, from the parameter estimation, we deduce the overestimated excess noise and the underestimated transmittance, which lead to a reduction in the final secret key rate. Simultaneously, we propose an estimation method of the measurement angular error. Next, the practical security analysis is provided in detail, and the effect of the measurement angular error and its corresponding compensation scheme are demonstrated. We conclude that measurement angular error severely degrades the security, but the proposed calibration and compensation method can significantly help improve the performance of the practical CV-QKD systems.

arXiv comment8 pages,6 figures

References in corpus (31)

• Gaussian Quantum Information
• Advances in Quantum Cryptography
• Secure quantum key distribution with realistic devices
• Quantum key distribution using gaussian-modulated coherent states
• Fundamental Limits of Repeaterless Quantum Communications
• General Benchmarks for Quantum Repeaters
• Experimental demonstration of long-distance continuous-variable quantum key distribution
• Unconditional optimality of Gaussian attacks against continuous-variable QKD
• Quantum key distribution over 25 km with an all-fiber continuous-variable system
• Optimality of Gaussian Attacks in Continuous Variable Quantum Cryptography
• High-rate quantum cryptography in untrusted networks
• Long-Distance Continuous-Variable Quantum Key Distribution over 202.81 km of Fiber
• Composable security proof for continuous-variable quantum key distribution with coherent states
• A de Finetti representation theorem for infinite dimensional quantum systems and applications to quantum cryptography
• Preventing Calibration Attacks on the Local Oscillator in Continuous-Variable Quantum Key Distribution
• Implementation of Continuous-Variable Quantum Key Distribution with Composable and One-Sided-Device-Independent Security Against Coherent Attacks
• Security of continuous-variable quantum key distribution via a Gaussian de Finetti reduction
• Security of continuous-variable quantum key distribution against general attacks
• Local oscillator fluctuation opens a loophole for Eve in practical continuous-variable quantum-key-distribution systems
• Quantum Hacking on Continuous-Variable Quantum Key Distribution System using a Wavelength Attack
• Characterization of Collective Gaussian Attacks and Security of Coherent-State Quantum Cryptography
• Experimental demonstration of Gaussian protocols for one-sided device-independent quantum key distribution
• Generating the local oscillator "locally" in continuous-variable quantum key distribution based on coherent detection
• Continuous-variable QKD over 50km commercial fiber
• Limits and Security of Free-Space Quantum Communications
• Satellite Quantum Communications: Fundamental Bounds and Practical Security
• Quantum hacking: saturation attack on practical continuous-variable quantum key distribution
• Self-coherent phase reference sharing for continuous-variable quantum key distribution
• High-speed Gaussian modulated continuous-variable quantum key distribution with a local local oscillator based on pilot-tone-assisted phase compensation
• Quantum Hacking on Quantum Key Distribution using Homodyne Detection
• Polarization attack on continuous-variable quantum key distribution