The estimation of key rate is an important aspect of the quantum key distribution process, especially in the use of dead time. In this paper, we demonstrate a numerical simulation to estimate the average detection pro...The estimation of key rate is an important aspect of the quantum key distribution process, especially in the use of dead time. In this paper, we demonstrate a numerical simulation to estimate the average detection probability and the key rate. Using our method, the estimated average detection probability is better than the previous result. Besides, we can easily find the best dead time, especially when considering the impact of after pulse.展开更多
Free-space quantum key distribution(QKD)offers broader geographical coverage and more flexible system deployment than fiber-based systems.However,the free-space environment is highly complex,and various attenuation fa...Free-space quantum key distribution(QKD)offers broader geographical coverage and more flexible system deployment than fiber-based systems.However,the free-space environment is highly complex,and various attenuation factors can significantly reduce the key distribution efficiency or even lead to encoding failures.This paper discusses and analyzes the impact of turbulence and fog in mountainous environments on free-space discrete-variable quantum key distribution.Through numerical simulation,this study examines the effects of altitude and visibility on transmittance and turbulence intensity,finding that turbulence intensity decreases with increasing altitude while transmittance increases;improvements in visibility also lead to increased transmittance.Beam wandering due to turbulence is also dominant.Combining these factors,the effects on the total transmittance and the secret key rate are taken into consideration.Our work could provide a reference for the deployment of practical QKD systems in actual mountainous environments.展开更多
Quantum key distribution(QKD)is a method for secure communication that utilizes quantum mechanics principles to distribute cryptographic keys between parties.Integrated photonics offer benefits such as compactness,sca...Quantum key distribution(QKD)is a method for secure communication that utilizes quantum mechanics principles to distribute cryptographic keys between parties.Integrated photonics offer benefits such as compactness,scalability,energy efficiency and the potential for extensive integration.We have achieved BB84 phase encoding and decoding,time-bin phase QKD,and the coherent one-way(COW)protocol on a planar lightwave circuit(PLC)platform.At the optimal temperature,our chip successfully prepared quantum states,performed decoding and calculated the secure key rate of the time-bin phasedecoding QKD to be 80.46 kbps over a 20 km transmission with a quantum bit error rate(QBER)of 4.23%.The secure key rate of the COW protocol was 18.18 kbps,with a phase error rate of 3.627%and a time error rate of 0.377%.The uniqueness of this technology lies in its combination of high integration and protocol flexibility,providing an innovative solution for the development of future quantum communication networks.展开更多
The advantage distillation(AD)technology has been proven to effectively improve the secret key rate and the communication distance of quantum key distribution(QKD).The mode-pairing quantum key distribution(MP-QKD)prot...The advantage distillation(AD)technology has been proven to effectively improve the secret key rate and the communication distance of quantum key distribution(QKD).The mode-pairing quantum key distribution(MP-QKD)protocol can overcome a fundamental physical limit,known as the Pirandola-Laurenza-Ottaviani-Banchi bound,without requiring global phase-locking.In this work,we propose a method based on multi-step AD to further enhance the performance of MP-QKD.The simulation results show that,compared to one-step AD,multi-step AD achieves better performance in long-distance scenarios and can tolerate a higher quantum bit error rate.Specifically,when the difference between the communication distances from Alice and Bob to Charlie is 25 km,50 km and 75 km,and the corresponding transmission distance exceeds 523 km,512 km and 496 km,respectively,the secret key rate achieved by multi-step AD surpasses that of one-step AD.Our findings indicate that the proposed method can effectively promote the application of MP-QKD in scenarios with high loss and high error rate.展开更多
A mode-pairing quantum key distribution based on heralded pair-coherent source with passive decoy-states is proposed,named HPCS-PDS-MP-QKD protocol,where the light sources at Alice and Bob sides are changed to heralde...A mode-pairing quantum key distribution based on heralded pair-coherent source with passive decoy-states is proposed,named HPCS-PDS-MP-QKD protocol,where the light sources at Alice and Bob sides are changed to heralded pair-coherent sources,and devices designed to implement passive decoy states are included at the transmitter sides to generate the decoy state pulses in the decoy-state window passively.With the defined efficient events and the designed pairing strategy,the key bits and bases can be obtained by data post-processing.Numerical simulation results verify the feasibility of the proposed protocol.The results show that the proposed protocol can exceed PLOB when the pairing interval setting is greater than 10^(3),and the transmission distance exceeds 200 km.When the key transmission distance reaches 300 km and the maximum pairing interval is equivalent to 1,its performance is improved by nearly 1.8 times compared to the original MP-QKD protocol with a weak coherent source(WCS-MP-QKD),and by 6.8 times higher than that of WCS-MPQKD with passive decoy states(WCS-PDS-MP-QKD).Meanwhile,the key transmission distance can reach 480 km,and surpasses the WCS-PDS-MP-QKD protocol by nearly 40 km.When the total pulse length is greater than 10^(11),the key generation rate is almost equal to that of infinite pulses.It is a promising QKD protocol that breaks the PLOB bound without requiring phase tracking and locking,has a longer transmission distance and a higher key generation rate,and eliminates the potential of side channel attack.展开更多
Secret key generation(SKG)is an emerging technology to secure wireless communication from attackers.Therefore,the SKG at the physical layer is an alternate solution over traditional cryptographic methods due to wirele...Secret key generation(SKG)is an emerging technology to secure wireless communication from attackers.Therefore,the SKG at the physical layer is an alternate solution over traditional cryptographic methods due to wireless channels’uncertainty.However,the physical layer secret key generation(PHY-SKG)depends on two fundamental parameters,i.e.,coherence time and power allocation.The coherence time for PHY-SKG is not applicable to secure wireless channels.This is because coherence time is for a certain period of time.Thus,legitimate users generate the secret keys(SKs)with a shorter key length in size.Hence,an attacker can quickly get information about the SKs.Consequently,the attacker can easily get valuable information from authentic users.Therefore,we considered the scheme of power allocation to enhance the secret key generation rate(SKGR)between legitimate users.Hence,we propose an alternative method,i.e.,a power allocation,to improve the SKGR.Our results show 72%higher SKGR in bits/sec by increasing power transmission.In addition,the power transmission is based on two important parameters,i.e.,epsilon and power loss factor,as given in power transmission equations.We found out that a higher value of epsilon impacts power transmission and subsequently impacts the SKGR.The SKGR is approximately 40.7%greater at 250 from 50 mW at epsilon=1.The value of SKGR is reduced to 18.5%at 250 mW when epsilonis 0.5.Furthermore,the transmission power is also measured against the different power loss factor values,i.e.,3.5,3,and 2.5,respectively,at epsilon=0.5.Hence,it is concluded that the value of epsilon and power loss factor impacts power transmission and,consequently,impacts the SKGR.展开更多
Similar to device-independent quantum key distribution （DI-QKD）, semi-device-independent quantum key distribu- tion （SDI-QKD） provides secure key distribution without any assumptions about the internal workings of...Similar to device-independent quantum key distribution （DI-QKD）, semi-device-independent quantum key distribu- tion （SDI-QKD） provides secure key distribution without any assumptions about the internal workings of the QKD devices. The only assumption is that the dimension of the Hilbert space is bounded. But SDI-QKD can be implemented in a one- way prepare-and-measure configuration without entanglement compared with DI-QKD. We propose a practical SDI-QKD protocol with four preparation states and three measurement bases by considering the maximal violation of dimension witnesses and specific processes of a QKD protocol. Moreover, we prove the security of the SDI-QKD protocol against collective attacks based on the min-entropy and dimension witnesses. We also show a comparison of the secret key rate between the SDI-QKD protocol and the standard QKD.展开更多
Quantum key distribution(QKD) generates information-theoretical secure keys between two parties based on the physical laws of quantum mechanics. The phase-matching(PM) QKD protocol allows the key rate to break the qua...Quantum key distribution(QKD) generates information-theoretical secure keys between two parties based on the physical laws of quantum mechanics. The phase-matching(PM) QKD protocol allows the key rate to break the quantum channel secret key capacity limit without quantum repeaters, and the security of the protocol is demonstrated by using equivalent entanglement. In this paper, the wavelength division multiplexing(WDM) technique is applied to the PM-QKD protocol considering the effect of crosstalk noise on the secret key rate. The performance of PM-QKD protocol based on WDM with the influence of adjacent classical channels and Raman scattering is analyzed by numerical simulations to maximize the total secret key rate of the QKD, providing a reference for future implementations of QKD based on WDM techniques.展开更多
Continuous-variable quantum key distribution(CVQKD)allows legitimate parties to extract and exchange secret keys.However,the tradeoff between the secret key rate and the accuracy of parameter estimation still around t...Continuous-variable quantum key distribution(CVQKD)allows legitimate parties to extract and exchange secret keys.However,the tradeoff between the secret key rate and the accuracy of parameter estimation still around the present CVQKD system.In this paper,we suggest an approach for parameter estimation of the CVQKD system via artificial neural networks(ANN),which can be merged in post-processing with less additional devices.The ANN-based training scheme,enables key prediction without exposing any raw key.Experimental results show that the error between the predicted values and the true ones is in a reasonable range.The CVQKD system can be improved in terms of the secret key rate and the parameter estimation,which involves less additional devices than the traditional CVQKD system.展开更多
The secure key rate of quantum key distribution(QKD)is greatly reduced because of the untrusted devices.In this paper,to raise the secure key rate of QKD,a device-independent quantum key distribution(DIQKD)protocol is...The secure key rate of quantum key distribution(QKD)is greatly reduced because of the untrusted devices.In this paper,to raise the secure key rate of QKD,a device-independent quantum key distribution(DIQKD)protocol is proposed based on hyper-entangled states and Bell inequalities.The security of the protocol is analyzed against the individual attack by an adversary only limited by the no-signaling condition.Based on the formalization of Clauser-Horne Shimony-Holt(CHSH)violation measurement on local correlation,the probability of a secure secret bit is obtained,which is produced by a pair of hyper-entangled particles.By analyzing the secure secret bit,it is proven that,when both the polarization mode and the path mode contains entangled-states,the DIQKD protocol gets a better secure key rate than common Bell states.展开更多
Reference-frame-independent quantum key distribution(RFI-QKD)can allow a quantum key distribution system to obtain the ideal key rate and transmission distance without reference system calibration,which has attracted ...Reference-frame-independent quantum key distribution(RFI-QKD)can allow a quantum key distribution system to obtain the ideal key rate and transmission distance without reference system calibration,which has attracted much attention.Here,we propose an RFI-QKD protocol based on wavelength division multiplexing(WDM)considering finite-key analysis and crosstalk.The finite-key bound for RFI-QKD with decoy states is derived under the crosstalk of WDM.The resulting secret key rate of RFI-QKD,which is more rigorous,is obtained.Simulation results reveal that the secret key rate of RFI-QKD based on WDM is affected by the multiplexing channel number,as well as crosstalk between adjacent channels.展开更多
In quantum key distribution（QKD）, the times of arrival of single photons are important for the keys extraction and time synchronization. The time-of-arrival（TOA） accuracy can affect the quantum bit error rate（QBE...In quantum key distribution（QKD）, the times of arrival of single photons are important for the keys extraction and time synchronization. The time-of-arrival（TOA） accuracy can affect the quantum bit error rate（QBER） and the final key rate. To achieve a higher accuracy and a better QKD performance, different from designing more complicated hardware circuits, we present a scheme that uses the mean TOA of M frequency-entangled photons to replace the TOA of a single photon. Moreover, to address the problem that the entanglement property is usually sensitive to the photon loss in practice,we further propose two schemes, which adopt partially entangled photons and grouping-entangled photons, respectively.In addition, we compare the effects of these three alternative schemes on the QKD performance and discuss the selection strategy for the optimal scheme in detail. The simulation results show that the proposed schemes can improve the QKD performance compared to the conventional single-photon scheme obviously, which demonstrate the effectiveness of the proposed schemes.展开更多
Establishing secure data communication necessitates secure key exchange over a public channel.Quantum key distribution(QKD),which leverages the principles of quantum physics,can achieve this with information-theoretic...Establishing secure data communication necessitates secure key exchange over a public channel.Quantum key distribution(QKD),which leverages the principles of quantum physics,can achieve this with information-theoretic security.The discrete modulated(DM)continuous variable(CV)QKD protocol,in particular,is a suitable candidate for large-scale deployment of quantum-safe communication due to its simplicity and compatibility with standard high-speed telecommunication technology.Here,we present the first experimental demonstration of a four-state DM CVQKD system,successfully generating composable finite-size keys,secure against collective attacks over a 20 km fiber channel with 2.3×10^(9) coherent quantum states,achieving a positive composable key rate of 11.04×10^(-3) bits/symbol.This accomplishment is enabled by using an advanced security proof,meticulously selecting its parameters,and the fast,stable operation of the system.Our results mark a significant step toward the large-scale deployment of practical,high-performance,cost-effective,and highly secure quantum key distribution networks using standard telecommunication components.展开更多
As one of the main application directions of quantum technology,underwater quantum communication is of great research significance.In order to study the influence of marine planktonic algal particles on the communicat...As one of the main application directions of quantum technology,underwater quantum communication is of great research significance.In order to study the influence of marine planktonic algal particles on the communication performance of underwater quantum links,based on the extinction characteristics of marine planktonic algal particles,the influence of changes in the chlorophyll concentration and particle number density of planktonic algal particles on the attenuation of underwater links is explored respectively,the influence of marine planktonic algal particles on the fidelity of underwater quantum links,the generation rate of the security key,and the utilization rate of the channel is analyzed,and simulation experiments are carried out.The results show that with the increase in chlorophyll concentration and particle density of aquatic planktonic algal particles,quantum communication channel link attenuation shows a gradually increasing trend.In addition,the security key generation rate,channel fidelity and utilization rate are gradually decreasing.Therefore,the performance of underwater quantum communication channel will be interfered by marine planktonic algal particles,and it is necessary to adjust the relevant parameter values in the quantum communication system according to different marine planktonic algal particle number density and chlorophyll concentration to improve the performance of quantum communication.展开更多
With the widespread application of quantum communication technology,there is an urgent need to enhance unconditionally secure key rates and capacity.Measurement-device-independent quantum key distribution(MDI-QKD),pro...With the widespread application of quantum communication technology,there is an urgent need to enhance unconditionally secure key rates and capacity.Measurement-device-independent quantum key distribution(MDI-QKD),proven to be immune to detection-side channel attacks,is a secure and reliable quantum communication scheme.The core of this scheme is Hong–Ou–Mandle(HOM)interference,a quantum optical phenomenon with no classical analog,where identical photons meeting on a symmetric beam splitter(BS)undergo interference and bunching.Any differences in the degrees of freedom(frequency,arrival time,spectrum,polarization,and the average number of photons per pulse)between the photons will deteriorate the interference visibility.Here,we demonstrate 16-channel weak coherent pulses(WCPs)of HOM interference with all channels’interference visibility over 46%based on two independent frequency-post-aligned soliton microcombs(SMCs).In our experiment,full locking and frequency alignment of the comb teeth between the two SMCs were achieved through pump frequency stabilization,SMC repetition rate locking,and fine tuning of the repetition rate.This demonstrates the feasibility of using independently generated SMCs as multi-wavelength sources for quantum communication.Meanwhile,SMC can achieve hundreds of frequency-stable comb teeth by locking only two parameters,which further reduces the complexity of frequency locking and the need for finding sufficient suitable frequency references compared to independent laser arrays.展开更多
Traditional virtual private networks（ VPNs） are conditional security. In order to ensure the security and confidentiality of user data transmission,a model of quantum VPN based on Internet protocol security（ IPSec...Traditional virtual private networks（ VPNs） are conditional security. In order to ensure the security and confidentiality of user data transmission,a model of quantum VPN based on Internet protocol security（ IPSec）protocol is proposed. By using quantum keys for key distribution and entangled particles for identity authentication in the network,a secure quantum VPN is relized. The important parameters affecting the performance of the VPN was analyzed. The quantitative relationship between the security key generation rate,the quantum bit error rate（ QBER） and the transmission distance was obtained. The factors that affect the system throughput were also analyzed and simulated. Finally,the influence of the quantum noise channel on the entanglement swapping was analyzed. Theoretical analysis and simulation results show that,under a limited number of decoy states,with the transmission distance increased from 0 to 112. 5 km,the secure key generation rate was reduced from 5. 63 × 10^-3 to 1. 22 × 10^-5. When the number of decoy states is fixed,the QBER increases dramatically with the increase of the transmission distance,and the maximum reaches 0. 393. Analysis shows that various factors in communication have a significant impact on system throughput. The generation rate of the effective entanglement photon pairs have decisive effect on the system throughput. Therefore,in the process of quantum VPN communication,various parameters of the system should be properly adjusted to communicate within a safe transmission distance,which can effectively improve the reliability of the quantum communication system.展开更多
基金Project supported by the National High Technology Research and Development Program of China (863 Program) (GrantNo. 2009AA01A349)
文摘The estimation of key rate is an important aspect of the quantum key distribution process, especially in the use of dead time. In this paper, we demonstrate a numerical simulation to estimate the average detection probability and the key rate. Using our method, the estimated average detection probability is better than the previous result. Besides, we can easily find the best dead time, especially when considering the impact of after pulse.
文摘Free-space quantum key distribution(QKD)offers broader geographical coverage and more flexible system deployment than fiber-based systems.However,the free-space environment is highly complex,and various attenuation factors can significantly reduce the key distribution efficiency or even lead to encoding failures.This paper discusses and analyzes the impact of turbulence and fog in mountainous environments on free-space discrete-variable quantum key distribution.Through numerical simulation,this study examines the effects of altitude and visibility on transmittance and turbulence intensity,finding that turbulence intensity decreases with increasing altitude while transmittance increases;improvements in visibility also lead to increased transmittance.Beam wandering due to turbulence is also dominant.Combining these factors,the effects on the total transmittance and the secret key rate are taken into consideration.Our work could provide a reference for the deployment of practical QKD systems in actual mountainous environments.
基金supported by the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0300701)the National Key Research and Development Program of China(Grant No.2018YFA0306403)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB43000000).
文摘Quantum key distribution(QKD)is a method for secure communication that utilizes quantum mechanics principles to distribute cryptographic keys between parties.Integrated photonics offer benefits such as compactness,scalability,energy efficiency and the potential for extensive integration.We have achieved BB84 phase encoding and decoding,time-bin phase QKD,and the coherent one-way(COW)protocol on a planar lightwave circuit(PLC)platform.At the optimal temperature,our chip successfully prepared quantum states,performed decoding and calculated the secure key rate of the time-bin phasedecoding QKD to be 80.46 kbps over a 20 km transmission with a quantum bit error rate(QBER)of 4.23%.The secure key rate of the COW protocol was 18.18 kbps,with a phase error rate of 3.627%and a time error rate of 0.377%.The uniqueness of this technology lies in its combination of high integration and protocol flexibility,providing an innovative solution for the development of future quantum communication networks.
基金supported by the National Natural Science Foundation of China(Grant Nos.62171144and 62031024)Guangxi Science Foundation(Grant Nos.2025GXNSFAA069137 and GXR-1BGQ2424005)Innovation Project of Guangxi Graduate Education(Grant No.YCBZ2025064)。
文摘The advantage distillation(AD)technology has been proven to effectively improve the secret key rate and the communication distance of quantum key distribution(QKD).The mode-pairing quantum key distribution(MP-QKD)protocol can overcome a fundamental physical limit,known as the Pirandola-Laurenza-Ottaviani-Banchi bound,without requiring global phase-locking.In this work,we propose a method based on multi-step AD to further enhance the performance of MP-QKD.The simulation results show that,compared to one-step AD,multi-step AD achieves better performance in long-distance scenarios and can tolerate a higher quantum bit error rate.Specifically,when the difference between the communication distances from Alice and Bob to Charlie is 25 km,50 km and 75 km,and the corresponding transmission distance exceeds 523 km,512 km and 496 km,respectively,the secret key rate achieved by multi-step AD surpasses that of one-step AD.Our findings indicate that the proposed method can effectively promote the application of MP-QKD in scenarios with high loss and high error rate.
基金Project supported by the National Natural Science Foundation of China(Grant No.62375140)the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(Grant No.KYCX241191 and SJCX250315)the Open Research Fund of the National Laboratory of Solid State Microstructures(Grant No.M36055)。
文摘A mode-pairing quantum key distribution based on heralded pair-coherent source with passive decoy-states is proposed,named HPCS-PDS-MP-QKD protocol,where the light sources at Alice and Bob sides are changed to heralded pair-coherent sources,and devices designed to implement passive decoy states are included at the transmitter sides to generate the decoy state pulses in the decoy-state window passively.With the defined efficient events and the designed pairing strategy,the key bits and bases can be obtained by data post-processing.Numerical simulation results verify the feasibility of the proposed protocol.The results show that the proposed protocol can exceed PLOB when the pairing interval setting is greater than 10^(3),and the transmission distance exceeds 200 km.When the key transmission distance reaches 300 km and the maximum pairing interval is equivalent to 1,its performance is improved by nearly 1.8 times compared to the original MP-QKD protocol with a weak coherent source(WCS-MP-QKD),and by 6.8 times higher than that of WCS-MPQKD with passive decoy states(WCS-PDS-MP-QKD).Meanwhile,the key transmission distance can reach 480 km,and surpasses the WCS-PDS-MP-QKD protocol by nearly 40 km.When the total pulse length is greater than 10^(11),the key generation rate is almost equal to that of infinite pulses.It is a promising QKD protocol that breaks the PLOB bound without requiring phase tracking and locking,has a longer transmission distance and a higher key generation rate,and eliminates the potential of side channel attack.
基金supported by the China National Key R&D Program(No.2018YFB0803600)Natural Science Foundation of China(No.61801008)+3 种基金Scientific Research Common Program of Beijing Municipal Education Commission(No.KM201910005025)the Chinese Postdoctoral Science Foundation(No.2020M670074)Key Project of Hunan Provincial,Department of Education(No.26420A205)The Construct Program of Applied Characteristics Discipline in Hunan University of Science and Engineering.
文摘Secret key generation(SKG)is an emerging technology to secure wireless communication from attackers.Therefore,the SKG at the physical layer is an alternate solution over traditional cryptographic methods due to wireless channels’uncertainty.However,the physical layer secret key generation(PHY-SKG)depends on two fundamental parameters,i.e.,coherence time and power allocation.The coherence time for PHY-SKG is not applicable to secure wireless channels.This is because coherence time is for a certain period of time.Thus,legitimate users generate the secret keys(SKs)with a shorter key length in size.Hence,an attacker can quickly get information about the SKs.Consequently,the attacker can easily get valuable information from authentic users.Therefore,we considered the scheme of power allocation to enhance the secret key generation rate(SKGR)between legitimate users.Hence,we propose an alternative method,i.e.,a power allocation,to improve the SKGR.Our results show 72%higher SKGR in bits/sec by increasing power transmission.In addition,the power transmission is based on two important parameters,i.e.,epsilon and power loss factor,as given in power transmission equations.We found out that a higher value of epsilon impacts power transmission and subsequently impacts the SKGR.The SKGR is approximately 40.7%greater at 250 from 50 mW at epsilon=1.The value of SKGR is reduced to 18.5%at 250 mW when epsilonis 0.5.Furthermore,the transmission power is also measured against the different power loss factor values,i.e.,3.5,3,and 2.5,respectively,at epsilon=0.5.Hence,it is concluded that the value of epsilon and power loss factor impacts power transmission and,consequently,impacts the SKGR.
基金Project supported by the National Basic Research Program of China(Grant No.2013CB338002)the National Natural Science Foundation of China(Grant Nos.11304397 and 11204379)
文摘Similar to device-independent quantum key distribution （DI-QKD）, semi-device-independent quantum key distribu- tion （SDI-QKD） provides secure key distribution without any assumptions about the internal workings of the QKD devices. The only assumption is that the dimension of the Hilbert space is bounded. But SDI-QKD can be implemented in a one- way prepare-and-measure configuration without entanglement compared with DI-QKD. We propose a practical SDI-QKD protocol with four preparation states and three measurement bases by considering the maximal violation of dimension witnesses and specific processes of a QKD protocol. Moreover, we prove the security of the SDI-QKD protocol against collective attacks based on the min-entropy and dimension witnesses. We also show a comparison of the secret key rate between the SDI-QKD protocol and the standard QKD.
基金supported by the State Key Laboratory of Information Photonics and Optical Communications (Beijing University of Posts and Telecommunications) (Grant No. IPOC2021ZT10)the National Natural Science Foundation of China (Grant No. 11904333)+1 种基金the Fundamental Research Funds for the Central Universities (Grant No. 2019XDA02)BUPT Innovation and Entrepreneurship Support Program (Grant No. 2022-YC-T051)。
文摘Quantum key distribution(QKD) generates information-theoretical secure keys between two parties based on the physical laws of quantum mechanics. The phase-matching(PM) QKD protocol allows the key rate to break the quantum channel secret key capacity limit without quantum repeaters, and the security of the protocol is demonstrated by using equivalent entanglement. In this paper, the wavelength division multiplexing(WDM) technique is applied to the PM-QKD protocol considering the effect of crosstalk noise on the secret key rate. The performance of PM-QKD protocol based on WDM with the influence of adjacent classical channels and Raman scattering is analyzed by numerical simulations to maximize the total secret key rate of the QKD, providing a reference for future implementations of QKD based on WDM techniques.
文摘Continuous-variable quantum key distribution(CVQKD)allows legitimate parties to extract and exchange secret keys.However,the tradeoff between the secret key rate and the accuracy of parameter estimation still around the present CVQKD system.In this paper,we suggest an approach for parameter estimation of the CVQKD system via artificial neural networks(ANN),which can be merged in post-processing with less additional devices.The ANN-based training scheme,enables key prediction without exposing any raw key.Experimental results show that the error between the predicted values and the true ones is in a reasonable range.The CVQKD system can be improved in terms of the secret key rate and the parameter estimation,which involves less additional devices than the traditional CVQKD system.
基金This work is supported by NSFC(Grant Nos.61572086,61402058)the Application Foundation Project of Sichuan Province of China(Grant No.2017JY0168)+3 种基金the National Key Research and Development Program(No.2017YFB0802302)Sichuan innovation team of quantum security communication(No.17TD0009)Sichuan academic and technical leaders training funding support projects(No.2016120080102643)the Fund for Middle and Young Academic Leaders of CUIT(Grant No.J201511).
文摘The secure key rate of quantum key distribution(QKD)is greatly reduced because of the untrusted devices.In this paper,to raise the secure key rate of QKD,a device-independent quantum key distribution(DIQKD)protocol is proposed based on hyper-entangled states and Bell inequalities.The security of the protocol is analyzed against the individual attack by an adversary only limited by the no-signaling condition.Based on the formalization of Clauser-Horne Shimony-Holt(CHSH)violation measurement on local correlation,the probability of a secure secret bit is obtained,which is produced by a pair of hyper-entangled particles.By analyzing the secure secret bit,it is proven that,when both the polarization mode and the path mode contains entangled-states,the DIQKD protocol gets a better secure key rate than common Bell states.
基金Project supported by the Fundamental Research Funds for the Central Universities,China(Grant No.2019XD-A02)the State Key Laboratory of Information Photonics and Optical Communications,Beijing University of Posts and Telecommunications(BUPT)(Grant No.IPOC2021ZT10)BUPT Innovation and Entrepreneurship Support Program(Grant No.2021-YC-A315).
文摘Reference-frame-independent quantum key distribution(RFI-QKD)can allow a quantum key distribution system to obtain the ideal key rate and transmission distance without reference system calibration,which has attracted much attention.Here,we propose an RFI-QKD protocol based on wavelength division multiplexing(WDM)considering finite-key analysis and crosstalk.The finite-key bound for RFI-QKD with decoy states is derived under the crosstalk of WDM.The resulting secret key rate of RFI-QKD,which is more rigorous,is obtained.Simulation results reveal that the secret key rate of RFI-QKD based on WDM is affected by the multiplexing channel number,as well as crosstalk between adjacent channels.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61573059,61401340,and 61172138)the Natural Science Basic Research Plan in Shaanxi Province of China(Grant No.2016JM6035)the Fundamental Research Funds for the Central Universities,China(Grant No.JB161303)
文摘In quantum key distribution（QKD）, the times of arrival of single photons are important for the keys extraction and time synchronization. The time-of-arrival（TOA） accuracy can affect the quantum bit error rate（QBER） and the final key rate. To achieve a higher accuracy and a better QKD performance, different from designing more complicated hardware circuits, we present a scheme that uses the mean TOA of M frequency-entangled photons to replace the TOA of a single photon. Moreover, to address the problem that the entanglement property is usually sensitive to the photon loss in practice,we further propose two schemes, which adopt partially entangled photons and grouping-entangled photons, respectively.In addition, we compare the effects of these three alternative schemes on the QKD performance and discuss the selection strategy for the optimal scheme in detail. The simulation results show that the proposed schemes can improve the QKD performance compared to the conventional single-photon scheme obviously, which demonstrate the effectiveness of the proposed schemes.
基金funded within the QuantERA II Programme(project CVSTAR)that has received funding from the European Union’s Horizon 2020 research and innovation program under Grant Agreement No 101017733Innovation Fund Denmark(IFD)under Grant Agreement No 731473+5 种基金the Austrian Research Promotion Agency(FFG),project number FO999891361from the European Union’s Digital Europe programme under Grant Agreement No 101091659(QCI.DK)from the European Union’s Horizon Europe research and innovation programme under the project“Quantum Security Networks Partnership”(QSNP,grant agreement no.101114043)A.A.E.H.,U.L.A.and T.G.acknowledge support from Innovation Fund Denmark(CryptQ,0175-00018A)the Danish National Research Foundation,Center for Macroscopic Quantum States(bigQ,DNRF142)A.A.E.H.,R.Z.and T.G.acknowledge funding from the Carlsberg Foundation,project CF21-0466.
文摘Establishing secure data communication necessitates secure key exchange over a public channel.Quantum key distribution(QKD),which leverages the principles of quantum physics,can achieve this with information-theoretic security.The discrete modulated(DM)continuous variable(CV)QKD protocol,in particular,is a suitable candidate for large-scale deployment of quantum-safe communication due to its simplicity and compatibility with standard high-speed telecommunication technology.Here,we present the first experimental demonstration of a four-state DM CVQKD system,successfully generating composable finite-size keys,secure against collective attacks over a 20 km fiber channel with 2.3×10^(9) coherent quantum states,achieving a positive composable key rate of 11.04×10^(-3) bits/symbol.This accomplishment is enabled by using an advanced security proof,meticulously selecting its parameters,and the fast,stable operation of the system.Our results mark a significant step toward the large-scale deployment of practical,high-performance,cost-effective,and highly secure quantum key distribution networks using standard telecommunication components.
基金funded by Youth Fund of the National Natural Science Foundation of China,grant number 11504176,61601230.
文摘As one of the main application directions of quantum technology,underwater quantum communication is of great research significance.In order to study the influence of marine planktonic algal particles on the communication performance of underwater quantum links,based on the extinction characteristics of marine planktonic algal particles,the influence of changes in the chlorophyll concentration and particle number density of planktonic algal particles on the attenuation of underwater links is explored respectively,the influence of marine planktonic algal particles on the fidelity of underwater quantum links,the generation rate of the security key,and the utilization rate of the channel is analyzed,and simulation experiments are carried out.The results show that with the increase in chlorophyll concentration and particle density of aquatic planktonic algal particles,quantum communication channel link attenuation shows a gradually increasing trend.In addition,the security key generation rate,channel fidelity and utilization rate are gradually decreasing.Therefore,the performance of underwater quantum communication channel will be interfered by marine planktonic algal particles,and it is necessary to adjust the relevant parameter values in the quantum communication system according to different marine planktonic algal particle number density and chlorophyll concentration to improve the performance of quantum communication.
基金Innovation Program for Quantum Science and Technology(2021ZD0300701,2021ZD0301500)CAS Project for Young Scientists in Basic Research(YSBR-069)+1 种基金National Natural Science Foundation of China(62075238,62205036)National Key Research and Development Program of China(2021YFB2800603)。
文摘With the widespread application of quantum communication technology,there is an urgent need to enhance unconditionally secure key rates and capacity.Measurement-device-independent quantum key distribution(MDI-QKD),proven to be immune to detection-side channel attacks,is a secure and reliable quantum communication scheme.The core of this scheme is Hong–Ou–Mandle(HOM)interference,a quantum optical phenomenon with no classical analog,where identical photons meeting on a symmetric beam splitter(BS)undergo interference and bunching.Any differences in the degrees of freedom(frequency,arrival time,spectrum,polarization,and the average number of photons per pulse)between the photons will deteriorate the interference visibility.Here,we demonstrate 16-channel weak coherent pulses(WCPs)of HOM interference with all channels’interference visibility over 46%based on two independent frequency-post-aligned soliton microcombs(SMCs).In our experiment,full locking and frequency alignment of the comb teeth between the two SMCs were achieved through pump frequency stabilization,SMC repetition rate locking,and fine tuning of the repetition rate.This demonstrates the feasibility of using independently generated SMCs as multi-wavelength sources for quantum communication.Meanwhile,SMC can achieve hundreds of frequency-stable comb teeth by locking only two parameters,which further reduces the complexity of frequency locking and the need for finding sufficient suitable frequency references compared to independent laser arrays.
基金supported by the National Natural Science Foundation of China(61172071)the International Scientific and Technological Cooperation and Exchange Program in Shaanxi Province,China(2015KW-013)the Scientific Research Program Funded by Shaanxi Provincial Education Department,China(16JK1711)
文摘Traditional virtual private networks（ VPNs） are conditional security. In order to ensure the security and confidentiality of user data transmission,a model of quantum VPN based on Internet protocol security（ IPSec）protocol is proposed. By using quantum keys for key distribution and entangled particles for identity authentication in the network,a secure quantum VPN is relized. The important parameters affecting the performance of the VPN was analyzed. The quantitative relationship between the security key generation rate,the quantum bit error rate（ QBER） and the transmission distance was obtained. The factors that affect the system throughput were also analyzed and simulated. Finally,the influence of the quantum noise channel on the entanglement swapping was analyzed. Theoretical analysis and simulation results show that,under a limited number of decoy states,with the transmission distance increased from 0 to 112. 5 km,the secure key generation rate was reduced from 5. 63 × 10^-3 to 1. 22 × 10^-5. When the number of decoy states is fixed,the QBER increases dramatically with the increase of the transmission distance,and the maximum reaches 0. 393. Analysis shows that various factors in communication have a significant impact on system throughput. The generation rate of the effective entanglement photon pairs have decisive effect on the system throughput. Therefore,in the process of quantum VPN communication,various parameters of the system should be properly adjusted to communicate within a safe transmission distance,which can effectively improve the reliability of the quantum communication system.
