Sub-Gbps key rate four-state continuous-variable quantum key distribution within metropolitan area

Wang, Heng; Li, Yang; Pi, Yaodi; Pan, Yan; Shao, Yun; Ma, Li; Zhang, Yichen; Yang, Jie; Zhang, Tao; Huang, Wei; Xu, Bingjie

doi:10.1038/s42005-022-00941-z

Cited by 49 publications

(16 citation statements)

References 39 publications

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“…By contrast, the LLO system can effectively solve the above problems. Recently, there have been many experimental implementations of LLO systems, both inside and outside the laboratory [14], [19], [20]. However, it is more difficult to recover the quantum signal compared with TLO systems, and introducing additional pilot signal is a great method in this way.…”

Section: Introductionmentioning

confidence: 99%

Experimental Demonstration of LLO Continuous-Variable Quantum Key Distribution With Polarization Loss Compensation

et al. 2023

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The compensation process for the state of polarization (SOP) from quantum signal plays an important role in the practical implementation of continuous-variable quantum key distribution (CV-QKD). In contrast to the previous scheme using an expensive digital dynamic polarization controller, we choose a cheaper manual polarization controller interfaced with a digital algorithm based on Kalman filter to achieve compensation of the polarization loss under the condition that the SOP of the fiber is relatively stable. This paper also enumerates the details of other digital signal processing method to achieve final secret key rate. And a pilot-sequential Gaussian modulated coherent state (GMCS) continuous-variable quantum key distribution system with a local local oscillator (LLO) is experimentally implemented based on the analysis of excess noise. Finally, the experimental results show that the method of polarization loss compensation takes advantages in maintaining the stability of the final secret key rate. And a secret key rate of 110 kbps is achieved within 20 km optical fiber (with 4 dB loss) under the finite-size block of 1 × 10 6 during a more extended time in the laboratory.

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Section: Introductionmentioning

confidence: 99%

Experimental Demonstration of LLO Continuous-Variable Quantum Key Distribution With Polarization Loss Compensation

et al. 2023

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“…Therefore, DMCS CVQKD has been widely researched by combining local local oscillator (LLO) scheme [18,19]. Recently, we experimentally demonstrated a sub-Gbps key rate four-state LLO-CVQKD within metropolitan area [20], where the achieved secure key rates are evaluated by using linear channel assuming (LCA) and semidefinite programming (SDP) security analysis method, respectively. However, the uncompact LCA security analysis method restricts the possible attacks performed by Eve and the SDP method depends on a lot of computational power for realizing the optimal solution of Z [21].…”

Section: Introductionmentioning

confidence: 99%

Experimental demonstration of 5 GBaud four-state continuous-variable quantum key distribution with digital signal processing

Wang¹,

Yan²,

Pi³

et al. 2023

Quantum and Nonlinear Optics IX

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In this paper, we experimentally demonstrate a 5 GBaud four-state continuous-variable quantum key distribution with digital signal processing. By employing a frequency-and polarization-multiplexing quantum key transceiver, the modulation noise and DAC quantization noise in quantum state preparation, the photo-leakage noise in co-fiber transmission, the detection noise and ADC quantization noise in polarization diversity detection can be effectively reduced for achieving an ultra-low level of excess noise. Moreover, the main polarization variation and phase noise can be accurately compensated by designing a precise digital compensation scheme including the pilot-assisted polarization and phase compensation algorithm and the data-assisted equalized compensation algorithm. Besides, the explicit asymptotic secure key rate is evaluated by using an improved semidefinite programming security analysis method, which achieves a 100 Mbps level of secure key rate within 10 km distance.

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“…To date, considerable research have been conducted to improve the protocol [ 1 , 25 ], and a high-rate LLO CVQKD based on Gaussian modulation up to 7.04 Mbits/s over 25-km optical fiber in the asymptotic limit [ 26 ]. More recently, the key rate based on discrete modulation CVQKD (in comparison to Gaussian modulation) has been improved by an order of magnitude [ 27 ]. Despite the outstanding superiority of the LLO CVQKD in simplifying the hardware required and circumventing the LO attacks, its performance improvement is still severely retarded by the relatively high phase noise [ 28 , 29 ].…”

Section: Introductionmentioning

confidence: 99%

Polarization Attack on Continuous-Variable Quantum Key Distribution with a Local Local Oscillator

Shao

Pan

Wang

et al. 2022

Entropy

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The estimation of phase noise of continuous-variable quantum key distribution protocol with a local local oscillator (LLO CVQKD), as a major process in quantifying the secret key rate, is closely relevant to the intensity of the phase reference. However, the transmission of the phase reference through the insecure quantum channel is prone to be exploited by the eavesdropper (Eve) to mount attacks. Here, we introduce a polarization attack scheme against the phase reference. Presently, in a practical LLO CVQKD system, only part of the phase reference pulses are measured to compensate for the polarization drift of the quantum signal pulses in a compensation cycle due to the limited polarization measurement rate, while the other part of the phase reference pulses are not measured. We show that Eve can control the phase noise by manipulating the polarization direction of the unmeasured phase reference to hide her attack on the quantum signal. Simulations show that Eve can obtain partial or total key rates information shared between Alice and Bob as the transmission distance increases. Improving the polarization measurement rate to 100% or monitoring the phase reference intensity in real-time is of great importance to protect the LLO CVQKD from polarization attack.

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Sub-Gbps key rate four-state continuous-variable quantum key distribution within metropolitan area

Cited by 49 publications

References 39 publications

Experimental Demonstration of LLO Continuous-Variable Quantum Key Distribution With Polarization Loss Compensation

Experimental Demonstration of LLO Continuous-Variable Quantum Key Distribution With Polarization Loss Compensation

Experimental demonstration of 5 GBaud four-state continuous-variable quantum key distribution with digital signal processing

Polarization Attack on Continuous-Variable Quantum Key Distribution with a Local Local Oscillator

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