High performance reconciliation for continuous-variable quantum key distribution with LDPC code

2015 ◽  
Vol 13 (02) ◽  
pp. 1550010 ◽  
Author(s):  
Dakai Lin ◽  
Duan Huang ◽  
Peng Huang ◽  
Jinye Peng ◽  
Guihua Zeng
Keyword(s):  
Quantum Key Distribution ◽  
Secure Communication ◽  
High Speed ◽  
High Performance ◽  
Graphics Processing Unit ◽  
Ldpc Code ◽  
Key Distribution ◽  
Continuous Variable ◽  
Processing Unit ◽  
Secret Key

Reconciliation is a significant procedure in a continuous-variable quantum key distribution (CV-QKD) system. It is employed to extract secure secret key from the resulted string through quantum channel between two users. However, the efficiency and the speed of previous reconciliation algorithms are low. These problems limit the secure communication distance and the secure key rate of CV-QKD systems. In this paper, we proposed a high-speed reconciliation algorithm through employing a well-structured decoding scheme based on low density parity-check (LDPC) code. The complexity of the proposed algorithm is reduced obviously. By using a graphics processing unit (GPU) device, our method may reach a reconciliation speed of 25 Mb/s for a CV-QKD system, which is currently the highest level and paves the way to high-speed CV-QKD.

scholarly journals Security Analysis of Discrete-Modulated Continuous-Variable Quantum Key Distribution over Seawater Channel

2019 ◽  
Vol 9 (22) ◽  
pp. 4956 ◽  
Author(s):  
Xinchao Ruan ◽  
Hang Zhang ◽  
Wei Zhao ◽  
Xiaoxue Wang ◽  
Xuan Li ◽  
...  
Keyword(s):  
Quantum Key Distribution ◽  
Secure Communication ◽  
Security Analysis ◽  
Finite Size ◽  
Key Distribution ◽  
Continuous Variable ◽  
Heterodyne Detection ◽  
Secret Key ◽  
Transmission Distance ◽  
Better Than

We investigate the optical absorption and scattering properties of four different kinds of seawater as the quantum channel. The models of discrete-modulated continuous-variable quantum key distribution (CV-QKD) in free-space seawater channel are briefly described, and the performance of the four-state protocol and the eight-state protocol in asymptotic and finite-size cases is analyzed in detail. Simulation results illustrate that the more complex is the seawater composition, the worse is the performance of the protocol. For different types of seawater channels, we can improve the performance of the protocol by selecting different optimal modulation variances and controlling the extra noise on the channel. Besides, we can find that the performance of the eight-state protocol is better than that of the four-state protocol, and there is little difference between homodyne detection and heterodyne detection. Although the secret key rate of the protocol that we propose is still relatively low and the maximum transmission distance is only a few hundred meters, the research on CV-QKD over the seawater channel is of great significance, which provides a new idea for the construction of global secure communication network.

scholarly journals Boosting higher secret key rate in quantum key distribution over mature telecom components

2021 ◽  
Author(s):  
Tao Wang ◽  
Peng Huang ◽  
Lang Li ◽  
Yingming Zhou ◽  
Guihua Zeng
Keyword(s):  
Distribution System ◽  
Quantum Key Distribution ◽  
Secure Communication ◽  
High Speed ◽  
Performance Indicator ◽  
Transmission Rate ◽  
Key Distribution ◽  
Low Noise ◽  
High Rate ◽  
Secret Key

Abstract Secret key rate is a core performance indicator in implementing quantum key distribution, which directly determines the transmission rate of enciphered data. Here we demonstrate a high-key-rate quantum key distribution system over mature telecom components. The entire framework of quantum key distribution over these components is constructed. The high-rate low-noise Gaussian modulation of coherent states is realized by a classical electro-optic IQ modulator. High-baud low-intensity quantum signals are received by a commercial integrated coherent receiver under the shot-noise limit. A series of digital signal processing algorithms are proposed to achieve accurate signal recovery and key distillation. The system has yield a secret key rate of 10.37 Mbps, 1.61 Mbps, 337.82 kbps, and 58.06 kbps under the standard telecom fiber of 20 km, 50 km, 70 km, and 100 km, respectively. Our results represent the achieved highest secret key generation rate for quantum key distribution using continuous variables at a standard telecom wavelength. Moreover, it breaks the isolation between quantum communication and classical optical communication in terms of components, and opens the way to a high-speed and cost-effective formation of metropolitan quantum secure communication networks.

scholarly journals Unidimensional Continuous-Variable Quantum Key Distribution with Untrusted Detection under Realistic Conditions

Entropy ◽  
2019 ◽  
Vol 21 (11) ◽  
pp. 1100 ◽  
Author(s):  
Luyu Huang ◽  
Yichen Zhang ◽  
Ziyang Chen ◽  
Song Yu
Keyword(s):  
Quantum Key Distribution ◽  
Coherent States ◽  
Secure Communication ◽  
Key Distribution ◽  
Continuous Variable ◽  
Third Party ◽  
Modulation Method ◽  
Secret Key ◽  
Long Distance ◽  
Quantum Key Distribution Protocol

A unidimensional continuous-variable quantum key distribution protocol with untrusted detection is proposed, where the two legitimate partners send unidimensional modulated or Gaussian-modulated coherent states to an untrusted third party, i.e., Charlie, to realize the measurement. Compared with the Gaussian-modulated coherent-state protocols, the unidimensional modulated protocols take the advantage of easy modulation, low cost, and only a small number of random numbers required. Security analysis shows that the proposed protocol cannot just defend all detectors side channels, but also achieve great performance under certain conditions. Specifically, three cases are discussed in detail, including using unidimensional modulated coherent states in Alice’s side, in Bob’s side, and in both sides under realistic conditions, respectively. Under the three conditions, we derive the expressions of the secret key rate and give the optimal gain parameters. It is found that the optimal performance of the protocol is achieved by using unidimensional modulated coherent states in both Alice’s and Bob’s side. The resulting protocol shows the potential for long-distance secure communication using the unidimensional quantum key distribution protocol with simple modulation method and untrusted detection under realistic conditions.

scholarly journals Feasibility of satellite-to-ground continuous-variable quantum key distribution

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Daniele Dequal ◽  
Luis Trigo Vidarte ◽  
Victor Roman Rodriguez ◽  
Giuseppe Vallone ◽  
Paolo Villoresi ◽  
...  
Keyword(s):  
Quantum Key Distribution ◽  
Secure Communication ◽  
Communication Systems ◽  
Channel Model ◽  
Finite Size ◽  
Key Distribution ◽  
Continuous Variable ◽  
Space Environment ◽  
Limiting Factor ◽  
Secret Key

AbstractEstablishing secure communication links at a global scale is a major potential application of quantum information science but also extremely challenging for the underlying technology. Although milestone experiments using satellite-to-ground links and exploiting singe-photon encoding for implementing quantum key distribution have shown recently that this goal is achievable, it is still necessary to further investigate practical solutions compatible with classical optical communication systems. Here, we examine the feasibility of establishing secret keys in a satellite-to-ground downlink configuration using continuous-variable encoding, which can be implemented using standard telecommunication components certified for space environment and able to operate at high symbol rates. Considering a realistic channel model and state-of-the-art technology, and exploiting an orbit subdivision technique for mitigating fluctuations in the transmission efficiency, we find positive secret key rates for a low-Earth-orbit scenario, whereas finite-size effects can be a limiting factor for higher orbits. Our analysis determines regions of values for important experimental parameters where secret key exchange is possible and can be used as a guideline for experimental efforts in this direction.

scholarly journals A novel error correction protocol for continuous variable quantum key distribution

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kadir Gümüş ◽  
Tobias A. Eriksson ◽  
Masahiro Takeoka ◽  
Mikio Fujiwara ◽  
Masahide Sasaki ◽  
...  
Keyword(s):  
Error Correction ◽  
Quantum Key Distribution ◽  
Ldpc Codes ◽  
Key Distribution ◽  
Continuous Variable ◽  
Early Termination ◽  
Parity Check ◽  
Secret Key ◽  
Ldpc Decoder ◽  
And Performance

AbstractReconciliation is a key element of continuous-variable quantum key distribution (CV-QKD) protocols, affecting both the complexity and performance of the entire system. During the reconciliation protocol, error correction is typically performed using low-density parity-check (LDPC) codes with a single decoding attempt. In this paper, we propose a modification to a conventional reconciliation protocol used in four-state protocol CV-QKD systems called the multiple decoding attempts (MDA) protocol. MDA uses multiple decoding attempts with LDPC codes, each attempt having fewer decoding iteration than the conventional protocol. Between each decoding attempt we propose to reveal information bits, which effectively lowers the code rate. MDA is shown to outperform the conventional protocol in regards to the secret key rate (SKR). A 10% decrease in frame error rate and an 8.5% increase in SKR are reported in this paper. A simple early termination for the LDPC decoder is also proposed and implemented. With early termination, MDA has decoding complexity similar to the conventional protocol while having an improved SKR.

scholarly journals Improving Underwater Continuous-Variable Measurement-Device-Independent Quantum Key Distribution via Zero-Photon Catalysis

Entropy ◽  
2020 ◽  
Vol 22 (5) ◽  
pp. 571
Author(s):  
Yuang Wang ◽  
Shanhua Zou ◽  
Yun Mao ◽  
Ying Guo
Keyword(s):  
Quantum Key Distribution ◽  
Single Photon ◽  
Elevation Angle ◽  
Key Distribution ◽  
Continuous Variable ◽  
Secret Key ◽  
Underwater Communications ◽  
Measurement Device ◽  
Transmission Distance ◽  
Measurement Device Independent

Underwater quantumkey distribution (QKD) is tough but important formodern underwater communications in an insecure environment. It can guarantee secure underwater communication between submarines and enhance safety for critical network nodes. To enhance the performance of continuous-variable quantumkey distribution (CVQKD) underwater in terms ofmaximal transmission distance and secret key rate as well, we adopt measurement-device-independent (MDI) quantum key distribution with the zero-photon catalysis (ZPC) performed at the emitter of one side, which is the ZPC-based MDI-CVQKD. Numerical simulation shows that the ZPC-involved scheme, which is a Gaussian operation in essence, works better than the single photon subtraction (SPS)-involved scheme in the extreme asymmetric case. We find that the transmission of the ZPC-involved scheme is longer than that of the SPS-involved scheme. In addition, we consider the effects of temperature, salinity and solar elevation angle on the system performance in pure seawater. The maximal transmission distance decreases with the increase of temperature and the decrease of sunlight elevation angle, while it changes little over a broad range of salinity

Comprehensive high-speed reconciliation for continuous-variable quantum key distribution

2020 ◽  
Vol 19 (9) ◽  
Author(s):  
Dabo Guo ◽  
Chao He ◽  
Tianhao Guo ◽  
Zhe Xue ◽  
Qiang Feng ◽  
...  
Keyword(s):  
Quantum Key Distribution ◽  
High Speed ◽  
Key Distribution ◽  
Continuous Variable

scholarly journals SECURITY OF A NEW TWO-WAY CONTINUOUS-VARIABLE QUANTUM KEY DISTRIBUTION PROTOCOL

2012 ◽  
Vol 10 (05) ◽  
pp. 1250059 ◽  
Author(s):  
MAOZHU SUN ◽  
XIANG PENG ◽  
YUJIE SHEN ◽  
HONG GUO
Keyword(s):  
Quantum Key Distribution ◽  
Key Distribution ◽  
Continuous Variable ◽  
Excess Noise ◽  
Noisy Channel ◽  
Quantum Channels ◽  
Secret Key ◽  
Transmission Distance ◽  
The Family ◽  
The One

The original two-way continuous-variable quantum-key-distribution (CV-QKD) protocols [S. Pirandola, S. Mancini, S. Lloyd and S. L. Braunstein, Nat. Phys. 4 (2008) 726] give the security against the collective attack on the condition of the tomography of the quantum channels. We propose a family of new two-way CV-QKD protocols and prove their security against collective entangling cloner attacks without the tomography of the quantum channels. The simulation result indicates that the new protocols maintain the same advantage as the original two-way protocols whose tolerable excess noise surpasses that of the one-way CV-QKD protocol. We also show that all sub-protocols within the family have higher secret key rate and much longer transmission distance than the one-way CV-QKD protocol for the noisy channel.

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