Key Reconciliation with Low-Density Parity-Check Codes for Long-Distance Quantum Cryptography
arXiv:1702.07740 · doi:10.1038/s41534-018-0070-6
Abstract
The speed at which two remote parties can exchange secret keys over a fixed-length fiber-optic cable in continuous-variable quantum key distribution (CV-QKD) is currently limited by the computational complexity of post-processing algorithms for key reconciliation. Multi-edge low-density parity-check (LDPC) codes with low code rates and long block lengths were proposed for CV-QKD, in order to extend the maximum reconciliation distance between the two remote parties. Key reconciliation over multiple dimensions has been shown to further improve the error-correction performance of multi-edge LDPC codes in CV-QKD, thereby increasing both the secret key rate and distance. However, the computational complexity of LDPC decoding for long block lengths on the order of 10^6 bits remains a challenge. This work introduces a quasi-cyclic (QC) code construction for multi-edge LDPC codes that is highly suitable for hardware-accelerated decoding on a modern graphics processing unit (GPU). When combined with an 8-dimensional reconciliation scheme, the LDPC decoder achieves a raw decoding throughput of 1.72Mbit/s and an information throughput of 7.16Kbit/s using an NVIDIA GeForce GTX 1080 GPU at a maximum distance of 160km with a secret key rate of 4.10x10^{-7} bits/pulse for a rate 0.02 multi-edge code with block length of 10^6 bits when finite-size effects are considered. This work extends the previous maximum CV-QKD distance of 100km to 160km, while delivering between 1.07x and 8.03x higher decoded information throughput over the upper bound on the secret key rate for a lossy channel. The GPU-based QC-LDPC decoder achieves a 1.29x improvement in throughput over the best existing GPU decoder implementation for a rate 1/10 multi-edge LDPC code with block length of 2^{20} bits. These results show that LDPC decoding is no longer the computational bottleneck in long-distance CV-QKD.
23 pages, 22 figures, 4 tables, 97 references
References in corpus (13)
- Quantum cryptography: Public key distribution and coin tossing
- Secure Quantum Key Distribution
- Measurement device independent quantum key distribution over 404 km optical fibre
- Unconditional optimality of Gaussian attacks against continuous-variable QKD
- Quantum key distribution over 25 km with an all-fiber continuous-variable system
- Composable security proof for continuous-variable quantum key distribution with coherent states
- Field and long-term demonstration of a wide area quantum key distribution network
- Continuous Variable Quantum Cryptography using Two-Way Quantum Communication
- Coexistence of high-bit-rate quantum key distribution and data on optical fiber
- Multidimensional reconciliation for continuous-variable quantum key distribution
- Characterization of Collective Gaussian Attacks and Security of Coherent-State Quantum Cryptography
- High Bit Rate Continuous-Variable Quantum Key Distribution
- Rate Compatible Protocol for Information Reconciliation: An application to QKD
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- Satellite-Based Continuous-Variable Quantum Communications: State-of-the-Art and a Predictive Outlook
- Explicit asymptotic secret key rate of continuous-variable quantum key distribution with an arbitrary modulation
- High speed error correction for continuous-variable quantum key distribution with multi-edge type LDPC code
- Continuous-Variable Quantum Key Distribution with Rateless Reconciliation Protocol
- Long-distance continuous-variable measurement-device-independent quantum key distribution with discrete modulation
- Terahertz Quantum Cryptography
- Rate compatible reconciliation for continuous-variable quantum key distribution using Raptor-like LDPC codes
- Continuous-variable quantum cryptography with discrete alphabets: Composable security under collective Gaussian attacks
- Trusted detector noise analysis for discrete modulation schemes of continuous-variable quantum key distribution
- Modular network for high-rate quantum conferencing
- Practical Continuous-variable Quantum Key Distribution with Feasible Optimization Parameters
- Applicability of Squeezed-and Coherent-State Continuous-Variable Quantum Key Distribution over Satellite Links
- Gaussian one-way thermal quantum cryptography with finite-size effects
- Finding and breaking the realistic rate-distance limit of continuous variable quantum key distribution
- Continuous-variable quantum communication
- Advantages of the coherent state compared with squeeze state in unidimensional continuous variable quantum key distribution
- Optimised Multithreaded CV-QKD Reconciliation for Global Quantum Networks
- Modelling Weak-Coherent CV-QKD Systems Using a Classical Simulation Framework
- An introductory review of the theory of continuous-variable quantum key distribution: Fundamentals, protocols, and security
- Efficient Reconciliation of Continuous Variable Quantum Key Distribution with Multiplicatively Repeated Non-Binary LDPC Codes
- Arbitrarily-high-dimensional reconciliation via cross-rotation for continuous-variable quantum key distribution
- Compact Continuous-Variable Quantum Key Distribution System Employing Monolithically Integrated Silicon Photonic Transceiver
- Continuous-Variable Quantum Key Distribution with Composable Security and Tight Error Correction Bound towards Constrained-Device Implementations