Composably secure data processing for Gaussian-modulated continuous variable quantum key distribution

Abstract

Continuous-variable (CV) quantum key distribution (QKD) employs the quadratures of a bosonic mode to establish a secret key between two remote parties, and this is usually achieved via a Gaussian modulation of coherent states. The resulting secret key rate depends not only on the loss and noise in the communication channel, but also on a series of data processing steps that are needed for transforming shared correlations into a final string of secret bits. Here we consider a Gaussian-modulated coherent-state protocol with homodyne detection in the general setting of composable finite-size security. After simulating the process of quantum communication, the output classical data is post-processed via procedures of parameter estimation, error correction, and privacy amplification. In particular, we analyze the high signal-to-noise regime which requires the use of high-rate (non-binary) low-density parity check codes. We implement all these steps in a Python-based library that allows one to investigate and optimize the protocol parameters to be used in practical experimental implementations of short-range CV-QKD.

Accepted version. The code for data-processing is available on github at https://github.com/softquanta/homCVQKD

References in corpus (7)

• Quantum cryptography: Public key distribution and coin tossing
• Long-Distance Continuous-Variable Quantum Key Distribution over 202.81 km of Fiber
• Characterization of Collective Gaussian Attacks and Security of Coherent-State Quantum Cryptography
• Limits and Security of Free-Space Quantum Communications
• Composable security for continuous variable quantum key distribution: Trust levels and practical key rates in wired and wireless networks
• Long-distance continuous-variable quantum key distribution with efficient channel estimation
• Numerical finite-key analysis of quantum key distribution

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• Continuous-variable quantum communication
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• A Survey on Continuous Variable Quantum Key Distribution for Secure Data Transmission: Toward the Future of Secured Quantum-Networks
• Fundamental limitations to key distillation from Gaussian states with Gaussian operations
• Realistic Threat Models for Fiber and Free-Space Continuous-Variable Quantum Key Distribution
• Data post-processing for the one-way heterodyne protocol under composable finite-size security
• Quantum key distribution with displaced thermal states
• Continuous-Variable Quantum Key Distribution with Composable Security and Tight Error Correction Bound towards Constrained-Device Implementations
• Optimizing Epsilon Security Parameters in QKD