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1.
测量设备无关量子密钥分发系统可以免疫任何针对探测器边信道的攻击, 并进一步结合诱惑态方法规避了准单光子源引入的实际安全性问题. 目前实验中一般采用弱相干光源, 但是该光源含有一定比例的空脉冲和多光子脉冲. 本文针对弱相干光源的具体特性, 采用量子力学的描述, 将各个器件进行量子化处理, 并同时考虑探测器的具体性能参数的影响, 分别给出了通信双方各自发送的脉冲含有特定光子数时产生的成功贝尔态和错误贝尔态的概率公式, 从理论上对相位编码和偏振编码测量设备无关量子密钥分发系统的误码率进行了定量分析, 分别推导并模拟了通信双方采用的平均光子数对称和不对称时误码率随传输距离的变化情况, 结果表明在偏振编码Z基中, 多光子脉冲不会引起误码; 在偏振编码X基和相位编码中, 受多光子影响, 产生的误码率较大. 对于不同的编码方式, 误码率均随传输距离的增加有不同程度的升高, 长距离传输时, 平均光子数越小, 产生的误码率越大; 在偏振编码X基和相位编码的短距离传输中, 相对于对称, 通信双方采用的平均光子数不对称时产生的误码率较大. 相似文献
2.
Lingzhi Kong 《中国物理 B》2022,31(9):90304-090304
We propose a new scheme to enhance the performance of the Gussian-modulated coherent-state continuous-variable measurement-device-independent quantum key distribution (CV-MDI-QKD) system via quantum scissors (QS) operation at Bob's side. As an non-deterministic amplifying setup, we firstly introduce the QS-enhanced CV-MDI-QKD protocol and then investigate the success probability of the QS operation in accordance with the equivalent one-way scheme. Afterwards, we investigate the effect of the QS operation on the proposed scheme and analyze the performance of the QS-enhanced CV-MDI-QKD system under the extreme asymmetric circumstance. Simulation results show that the QS operation can indeed improve the performance of the CV-MDI-QKD system considerably. QS-enhanced CV-MDI-QKD protocol outperforms the original CV-MDI-QKD protocol in both the maximum transmission distance and the secret key rate. Moreover, the better the performance of QS operation, the more significant the improvement of performance of the system. 相似文献
3.
In this paper, we study the thermodynamic features of a two-dimensional charged black hole. Weinhold curvature and Ruppeiner curvature are explored as information geometry, respectively. Moreover, based on the Legendre invariant proposed by Hernando Quevedo, the geometro-thermodynamics behavior of this black hole is investigated. 相似文献
4.
Recently, a novel reference-frame-independent measurement-device-independent quantum key distribution protocol was proposed, which can remove all detector side channels as well as tolerate unknown and slow variance of reference frame without active alignment. In this paper, we propose a new tomographic method to estimate the key rate in that protocol. We estimate the key rate using conventional method and tomographic method respectively and compare the two methods by numerical simulation. The numerical simulation results show that tomographic approach is equivalent to the conventional approach, which can be used as an alternative method. 相似文献
5.
Measurement-device-independent quantum cryptographic conferencing(MDI-QCC) protocol puts MDI quantum key distribution(MDI-QKD) forwards to multi-party applications, and suggests a significant framework for practical multi-party quantum communication. In order to mitigate the experimental complexity of MDI-QCC and remove the key assumption(the sources are trusted) in MDI-QCC, we extend the framework of MDI-QKD with an untrusted source to MDI-QCC and give the rigorous security analysis of MDI-QCC with an untrusted source. What is more, in the security analysis we clearly provide a rigorous analytical method for parameters' estimation, which with simple modifications can be applied to not only MDI-QKD with an untrusted source but also arbitrary multi-party communication protocol with an untrusted source. The simulation results show that at reasonable distances the asymptotic key rates for the two cases(with trusted and untrusted sources) almost overlap, which indicates the feasibility of our protocol. 相似文献
6.
In this paper, a continuous variable (CV) measurement-device-independent (MDI) quantum key distribution (QKD) protocol using Gaussian modulated coherent states is proposed. The MDI is first proposed to resist the attacks on the detection equipment by introducing an untrusted relay. However, the necessity of propagation of local oscillator between legitimate users and the relay makes the implementation of CV-MDI-QKD highly impractical. By introducing the plug-and-play (P&P) technique into CV-MDI-QKD, the problems of polarization drifts caused by environmental disturbance and the security loopholes during the local oscillator transmission are solved naturally. The proposed scheme is superior to the previous CV-MDI-QKD protocol on the aspect of implementation. The security bounds of the P&P CV-MDI-QKD under the Gaussian collective attack are analyzed. It is believed that the technique presented in this paper can be extended to quantum network. 相似文献
7.
As a multi-particle entangled state, the Greenberger–Horne–Zeilinger (GHZ) state plays an important role in quantum theory and applications. In this study, we propose a flexible multi-user measurement-device-independent quantum key distribution (MDI-QKD) scheme based on a GHZ entangled state. Our scheme can distribute quantum keys among multiple users while being resistant to detection attacks. Our simulation results show that the secure distance between each user and the measurement device can reach more than 280 km while reducing the complexity of the quantum network. Additionally, we propose a method to expand our scheme to a multi-node with multi-user network, which can further enhance the communication distance between the users at different nodes. 相似文献
8.
Reference-frame-independent measurement-device-independent QKD (RFI-MDI-QKD), immune to both the slow unknown drift of reference frames and detector side channel attacks, can generate information-theoretic secure keys. Despite its natural resistance to the slow drift of reference frames, the performance of practical RFI-MDI-QKD systems descends with the increasing drift of reference frames. In this paper, we demonstrate the worst relative rotation of reference frames for practical RFI-MDI-QKD systems, and investigate their performance against the worst-case scenario, both of which are unclear to date. Simulation results show that, practical RFI-MDI-QKD systems can achieve quite good performance even against the worst-case scenario, which clearly demonstrates that it is possible to implement practical MDI-QKD systems with freely drifting reference frames. 相似文献
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10.
Measurement-device-independent quantum key distribution(MDI-QKD)provides us a powerful approach to resist all attacks at detection side.Besides the unconditional security,people also seek for high key generation rate,but MDI-QKD has relatively low key generation rate.In this paper,we provide an efficient approach to increase the key generation rate of MDI-QKD by adopting multiple degrees of freedom(DOFs)of single photons to generate keys.Compared with other high-dimension MDI-QKD protocols encoding in one DOF,our protocol is more flexible,for our protocol generating keys in independent subsystems and the detection failure or error in a DOF not affecting the information encoding in other DOFs.Based on above features,our MDI-QKD protocol may have potential application in future quantum comniunication field. 相似文献
11.
测量设备无关量子密钥分发系统能够抵御任何针对单光子探测器边信道的攻击, 进一步结合诱惑态的方案, 可以同时规避准单光子源引起的实际安全漏洞. 测量设备无关量子密钥分发系统中, 非对称传输、分束器的不对称以及各个单光子探测器存在实际参数差异等光学系统的具体实现特征会对系统误码率和成码率等性能产生一定的影响. 本文针对采用弱相干光源的测量设备无关量子密钥分发系统, 引入单光子探测器品质因子的实验参数(暗计数与探测效率的比值), 通过量子化描述, 理论推导并模拟了误码率与单光子探测器品质因子、分束器反射率以及通信双方弱相干光源平均光子数之间的关系. 结果表明: 在X基偏振编码 和相位编码系统中, 当分束器的反射率趋近于0.5时, 误码率取最小值; 在偏振编码和相位编码系统中, 误码率随着单光子探测器品质因子的增大而增大; 在Z基偏振编码系统中, 误码率随分束器的反射率的变化会呈现较小的波动, 当分束器的反射率为0.5时, 若通信双方采用的平均光子数相差较大, 则误码率取最大值; 分束器的反射率和平均光子数对误码率的影响在Z基情况下不能等同, 但是对于X基编码和相位编码却能等同. 相似文献
12.
Statistical fluctuations are unavoidable in realistic quantum key distribution (QKD) due to finite-size effect. Based on the four-intensity proposal on measurement-device-independent QKD (MDI-QKD) in[Phys. Rev. A 93 (2016) 042324], we particularly analyze the scenario that only three intensities are used, namely a three-intensity decoy-state MDI-QKD with biased basis choice. After performing full parameter optimization method, simulations results demonstrate that this scenario can obtain distinct enhancement compared with the conventional unbiased threeintensity decoy-state method, e.g. Xu et al.'s[Phys. Rev. A 89 (2014) 052333]. Furthermore, results also show that it works more efficiently by using HSPS than using WCS at longer transmission distance. 相似文献
13.
We propose a novel scheme for measurement-device-independent (MDI) continuous-variable quantum key distribution (CVQKD) by simultaneously conducting classical communication and QKD, which is called “simultaneous MDI-CVQKD” protocol. In such protocol, each sender (Alice, Bob) can superimpose random numbers for QKD on classical information by taking advantage of the same weak coherent pulse and an untrusted third party (Charlie) decodes it by using the same coherent detectors, which could be appealing in practice due to that multiple purposes can be realized by employing only single communication system. What is more, the proposed protocol is MDI, which is immune to all possible side-channel attacks on practical detectors. Security results illustrate that the simultaneous MDI-CVQKD protocol can secure against arbitrary collective attacks. In addition, we employ phasesensitive optical amplifiers to compensate the imperfection existing in practical detectors. With this technology, even common practical detectors can be used for detection through choosing a suitable optical amplifier gain. Furthermore, we also take the finite-size effect into consideration and show that the whole raw keys can be taken advantage of to generate the final secret key instead of sacrificing part of them for parameter estimation. Therefore, an enhanced performance of the simultaneous MDI-CVQKD protocol can be obtained in finite-size regime. 相似文献
14.
Recently,the Hong-Ou-Mandel(HOM) interference between two independent weak coherent pulses(WCPs) has been paid much attention due to the measurement-device-independent(MDI) quantum key distribution(QKD).Using classical wave theory,articles reported before show that the visibility of this kind of HOM-type interference is ≤ 50%.In this work,we analyze this kind of interference using quantum optics,which reveals more details compared to the wave theory.Analyses confirm the maximum visibility of 50%.And we conclude that the maximum visibility of 50%comes from the two single-photon states in WCPs,without considering the noise.In the experiment,we successfully approach the visibility of 50%by using WCPs splitting from the single pico-second laser source and phase scanning.Since this kind of HOM interference is immune to slow phase fluctuations,both the realized and proposed experiment designs can provide stable ways of high-resolution optical distance detection. 相似文献
15.
Performance analysis of continuous-variable measurement-device-independent quantum key distribution under diverse weather conditions 
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下载免费PDF全文 《中国物理 B》2020,(2):109-116
The effects of weather conditions are ubiquitous in practical wireless quantum communication links.Here in this work,the performances of atmospheric continuous-variable measurement-device-independent quantum key distribution(CV-MDI-QKD) under diverse weather conditions are analyzed quantitatively.According to the Mie scattering theory and atmospheric CV-MDI-QKD model,we numerically simulate the relationship between performance of CV-MDI-QKD and the rainy and foggy conditions,aiming to get close to the actual combat environment in the future.The results show that both rain and fog will degrade the performance of the CV-MDI-QKD protocol.Under the rainy condition,the larger the raindrop diameter,the more obvious the extinction effect is and the lower the secret key rate accordingly.In addition,we find that the secret key rate decreases with the increase of spot deflection distance and the fluctuation of deflection.Under the foggy condition,the results illustrate that the transmittance decreases with the increase of droplet radius or deflection distance,which eventually yields the decrease in the secret key rate.Besides,in both weather conditions,the increase of transmission distance also leads the secret key rate to deteriorate.Our work can provide a foundation for evaluating the performance evaluation and successfully implementing the atmospheric CV-MDI-QKD in the future field operation environment under different weather conditions. 相似文献
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Simultaneous two-way classical and quantum (STCQ) communication combines both continuous classical coherent optical communication and continuous-variable quantum key distribution (CV-QKD), which eliminates all detection-related imperfections by being measurement-device-independent (MDI). In this paper, we propose a protocol relying on STCQ communication on the oceanic quantum channel, in which the superposition-modulation-based coherent states depend on the information bits of both the secret key and the classical communication ciphertext. We analyse the encoding combination in classical communication and consider the probability distribution transmittance under seawater turbulence with various interference factors. Our numerical simulations of various practical scenarios demonstrate that the proposed protocol can simultaneously enable two-way classical communication and CV-MDI QKD with just a slight performance degradation transmission distance compared to the original CV-MDI QKD scheme. Moreover, the asymmetric situation outperforms the symmetric case in terms of transmission distance and optical modulation variance. We further take into consideration the impact of finite-size effects to illustrate the applicability of the proposed scheme in practical scenarios. The results show the feasibility of the underwater STCQ scheme, which contributes toward developing a global quantum communication network in free space. 相似文献
18.
量子保密通信包括量子密钥分发、量子安全直接通信和量子秘密共享等主要形式.在量子密钥分发和秘密共享中,传输的是随机数而不是信息,要再经过一次经典通信才能完成信息的传输.在量子信道直接传输信息的量子通信形式是量子安全直接通信.基于量子隐形传态的量子通信(简称量子隐形传态通信)是否属于量子安全直接通信尚需解释.构造了一个量子隐形传态通信方案,给出了具体的操作步骤.与一般的量子隐形传态不同,量子隐形传态通信所传输的量子态是计算基矢态,大大简化了贝尔基测量和单粒子操作.分析结果表明,量子隐形传态通信等价于包含了全用型量子密钥分发和经典通信的复合过程,不是量子安全直接通信,其传输受到中间介质和距离的影响,所以不比量子密钥分发更有优势.将该方案与量子密钥分发、量子安全直接通信和经典一次性便笺密码方案进行对比,通过几个通信参数的比较给出各个方案的特点,还特别讨论了各方案在空间量子通信方面的特点. 相似文献
19.
We propose a new counterfactual quantum cryptography protocol concerning about distributing a deterministic key.By adding a controlled blocking operation module to the original protocol [T.G.Noh,Phys.Rev.Lett.103(2009) 230501],the correlation between the polarizations of the two parties,Alice and Bob,is extended,therefore,one can distribute both deterministic keys and random ones using our protocol.We have also given a simple proof of the security of our protocol using the technique we ever applied to the original protocol.Most importantly,our analysis produces a bound tighter than the existing ones. 相似文献
20.
We propose a discrete-modulated continuous-variable measurement-device-independent quantum key distribution protocol over a fiber-to-water channel. Different from optical fibers, the underwater channel has more severe optical attenuation because of optical absorption and scattering, which reduces the maximum communication distance. To enhance the performance of the protocol, the photon subtraction operation is implemented at the modulator side. We carry out a performance simulation in two different kinds of seawater channel, and the result shows that the scheme with photon subtraction has a longer secure communication distance under certain conditions. 相似文献