Efficient quantum private comparison protocol utilizing single photons and rotational encryption

As a branch of quantum secure multiparty computation,quantum private comparison is applied frequently in many fields,such as secret elections,private voting,and identification.A quantum private comparison protocol with higher efficiency and easier implementation is proposed in this paper.The private secrets are encoded as single polarized photons and then encrypted with a homomorphic rotational encryption method.Relying on this method and the circular transmission mode,we implement the multiplexing of photons,raising the efficiency of our protocol to 100%.Our protocol is easy to realize since only single photons,unitary operation,and single-particle measurement are introduced.Meanwhile,the analysis shows that our protocol is also correct and secure.

Efficient quantum private comparison protocol based on one direction discrete quantum walks on the circle

We propose an efficient quantum private comparison protocol firstly based on one direction quantum walks.With the help of one direction quantum walk,we develop a novel method that allows the semi-honest third party to set a flag to judge the comparing result,which improves the qubit efficiency and the maximum quantity of the participants’secret messages.Besides,our protocol can judge the size of the secret messages,not only equality.Furthermore,the quantum walks particle is disentangled in the initial state.It only requires a quantum walks operator to move,making our proposed protocol easy to implement and reducing the quantum resources.Through security analysis,we prove that our protocol can withstand well-known attacks and brute-force attacks.Analyses also reveal that our protocol is correct and practical.

Measure-Resend Semi-Quantum Private Comparison Scheme Using GHZ Class States

Quantum private comparison is an important topic in quantum cryptography.Recently,the idea of semi-quantumness has been often used in designing private comparison protocol,which allows some of the participants to remain classical.In this paper,we propose a semi quantum private comparison scheme based on Greenberge-Horne-Zeilinger(GHZ)class states,which allows two classical participants to compare the equality of their private secret with the help of a quantum third party(server).In the proposed protocol,server is semi-honest who will follow the protocol honestly,but he may try to learn additional information from the protocol execution.The classical participants’activities are restricted to either measuring a quantum state or reflecting it in the classical basis{0,1}.In addition,security and efficiency of the proposed schemes have been discussed.

Linear optical realization of unambiguous quantum state comparison

In this paper, we propose an experimental scheme for unambiguous quantum state comparison assisted by linear optical manipulations, twin-photons produced from parametric down-conversion, and postselection from the coincidence measurement. In this scheme the preparation of the general two mixed qubit states with arbitrary prior probabilities and the realization of the optimal POVMs for unambiguous quantum state comparison are presented. This proposal is feasible by current experimental technology, and may be used in single-qubit quantum fingerprinting.

Quantum private comparison of arbitrary single qubit states based on swap test

By using swap test,a quantum private comparison(QPC) protocol of arbitrary single qubit states with a semi-honest third party is proposed.The semi-honest third party(TP) is required to help two participants perform the comparison.She can record intermediate results and do some calculations in the whole process of the protocol execution,but she cannot conspire with any of participants.In the process of comparison,the TP cannot get two participants’ private information except the comparison results.According to the security analysis,the proposed protocol can resist both outsider attacks and participants’ attacks.Compared with the existing QPC protocols,the proposed one does not require any entanglement swapping technology,but it can compare two participants’ qubits by performing swap test,which is easier to implement with current technology.Meanwhile,the proposed protocol can compare secret integers.It encodes secret integers into the amplitude of quantum state rather than transfer them as binary representations,and the encoded quantum state is compared by performing the swap test.Additionally,the proposed QPC protocol is extended to the QPC of arbitrary single qubit states by using multi-qubit swap test.

New Quantum Private Comparison Using Hyperentangled GHZ State

In this paper,we propose a new protocol designed for quantum private comparison(QPC).This new protocol utilizes the hyperentanglement as the quantum resource and introduces a semi-honest third party(TP)to achieve the objective.This protocol’s quantum carrier is a hyperentangled three-photon GHZ state in 2 degrees of freedom(DOF),which could have 64 combinations.The TP can decide which combination to use based on the shared key information provided from a quantum key distribution(QKD)protocol.By doing so,the security of the protocol can be improved further.Decoy photon technology is also used as another means of security and checks if the transmission in the quantum channel is secure or not before sending the quantum carrier.The proposed protocol is proved to be able to fend off various kinds of eavesdropping attacks.In addition,the new QPC protocol also can compare secret inputs securely and efficiently.

A Comparison of the Concurrence and the Quantum Discord in a Two-Qubit System

The quantum correlation dynamics in an anisotropic Heisenberg XY Z model under decoherence are investigated with the use of concurrence C and quantum discord （QD）. There is a remarkable difference between the time evolution behaviors of these two correlation measures： there is a entanglement-sudden-death phenomenon in the concurrence while there is none in QD, which is valid for all of the initial states of this system, and the interval time of the entanglement death is found to be strongly dependent on the initial states and the parameters B and △. With the long-time limit the steady entanglement （SC） and steady quantum discord （SO, D） can be obtained. The magnitudes of SC and SQD are closely related to the parameters B and △, while the strength of the Dzyaloshinskii-Moriya interaction, D, has no influence. In addition, the effects of the parameters B and △ on SC and SQD display such different and complicated features that one cannot obtain a uniform law about them, thus we give an analytical explanation of this phenomenon. Lastly, it can be noted that the value of SC is not always larger than SQD, which is strongly dependent on the parameters B and △.

Faster than the Speed of Light Is a Quantum Phenomena

Classical Mechanics using Einstein’s theories of relativity places a limit on speed as the speed of light. Quantum Mechanics has no such limitation. To understand space accelerating faster than the speed of light and information being exchanged instantaneously between two entangled electrons separated by huge distances, one uses Planck’s length, Planck’s time, and Planck’s mass to indicate that space and time are discrete and therefore along with masses smaller than Planck’s mass are Quantum Mechanical in nature. Faster than the speed of light c = 3 × 108 m/s is a classical effect only in dimensions of space lower than our 3-D Universe, but it is a Quantum effect in all dimensions of space. Because space can oscillate sending out ripples from the source, it is the medium used for transporting light waves and gravity waves.

基于半量子安全直接通信的量子拍卖协议

针对现有量子密封拍卖协议中存在的报价隐私保护不够、恶意竞标者与第三方共谋等问题,提出了一种基于半量子安全直接通信的量子密封投标拍卖协议。该协议采用半量子安全直接通信,通信时拍卖方仅需拥有测量和反射粒子的能力;通过对投标方报价的保序加密,实现对报价的隐私保护;利用隐私比较,在无第三方参与的情况下,拍卖方也能比较保序加密后的报价信息。理论分析表明面对截获-重发、受控非门(CNOT)、相位反转、共谋等攻击时,所提出协议仍具有较高的安全性,且与同类型量子拍卖协议相比,新协议通信效率不受投标人数的影响。

Efficient error estimation in quantum key distribution

In a quantum key distribution（QKD） system, the error rate needs to be estimated for determining the joint probability distribution between legitimate parties, and for improving the performance of key reconciliation. We propose an efficient error estimation scheme for QKD, which is called parity comparison method（PCM）. In the proposed method, the parity of a group of sifted keys is practically analysed to estimate the quantum bit error rate instead of using the traditional key sampling. From the simulation results, the proposed method evidently improves the accuracy and decreases revealed information in most realistic application situations.

Quantum Key Distribution Scheme with High Efficiency

基于纠纷交换，一个量钥匙分发(QKD ) 计划被建议。在这个计划，秘密钥匙被比较起始的贝尔状态和纠纷交换的结果形成。而且，艾莉斯和鲍勃准备的所有起始的贝尔状态是完全任意的。作为在二个聚会之间交换的古典信息很小，这个 QKD 计划有高效率。另外，以便阻止偷听，圈套粒子被使用。

Relativistic Reduction of the Electron-Nucleus Force in Bohr’s Hydrogen Atom and the Time of Electron Transition between the Neighbouring Quantum Energy Levels

The aim of the paper is to get an insight into the time interval of electron emission done between two neighbouring energy levels of the hydrogen atom. To this purpose, in the first step, the formulae of the special relativity are applied to demonstrate the conditions which can annihilate the electrostatic force acting between the nucleus and electron in the atom. This result is obtained when a suitable electron speed entering the Lorentz transformation is combined with the strength of the magnetic field acting normally to the electron orbit in the atom. In the next step, the Maxwell equation characterizing the electromotive force is applied to calculate the time interval connected with the change of the magnetic field necessary to produce the force. It is shown that the time interval obtained from the Maxwell equation, multiplied by the energy change of two neighbouring energy levels considered in the atom, does satisfy the Joule-Lenz formula associated with the quantum electron energy emission rate between the levels.

双向隐私保护量子投票协议

量子投票协议是利用量子的部分特性设计的电子投票协议.目前的量子投票协议忽略了双向隐私保护,即在保证投票者隐私的前提下,对落选者投票信息的隐私保护.设计了一个六方参与的量子投票协议,应用五粒子纠缠态实现量子代理盲签名,应用半量子秘密比较协议实现票数的秘密比较.前者能够分离投票者身份信息和投票信息以实现对投票者隐私的保护,后者能够秘密比较候选人票数以实现对候选人隐私的保护.设计的量子投票协议以传统量子投票协议为框架,增添了新功能,投票过程安全可靠可监督,协议传统安全性和抗量子性得到了保证,且无过多量子资源的使用,可以实现完整的大基数投票过程.

基于半量子秘密比较的量子拍卖协议

针对量子密封拍卖协议中报价隐私保护不足、第三方不可信、对参与双方量子能力要求较高等情况,提出了一种将高能级单粒子作为信息载体的基于半量子秘密比较的量子密封投标拍卖协议。协议过程无需第三方参与,且采用半量子方式,仅要求拍卖方为强量子能力方,投标方仅需拥有反射粒子及制备单粒子的能力。协议利用半量子秘密比较,实现对投标方报价的隐私保护,拍卖方仅能获得报价之间的大小关系,而无法获取具体报价。文中通过理论分析证明了所提协议具有较高的安全性,能够抵御测量-重发攻击、截获-重发攻击、纠缠攻击、共谋攻击等多种攻击,且协议通信效率较稳定,不受投标人数的影响。

基于四粒子GHZ态的半量子私有比较协议

半量子通信协议允许只具有有限量子能力的参与者进行量子通信,与全量子通信协议相比,减少了量子资源损耗,节约了量子硬件成本。基于半量子模型,以四粒子Greenberger-Horne-Zeilinger(GHZ)态作为量子资源态,提出了一种新型半量子私有比较协议。该协议可以在半诚实第三方的帮助下比较两个经典用户Alice和Bob的信息是否相等,且不泄露他们的秘密信息。安全性分析表明该协议可以抵御内部攻击和外部攻击,与现有的半量子私有比较协议相比,经典用户所需的量子能力更少,只需执行Z基测量和反射接收的粒子,且具有较高的量子比特效率。此外,通过IBM量子云平台进行了仿真实验,验证了所提协议的正确性。

锁定参数与光钟稳定度关系的研究

从量子力学原理出发,结合光钟的锁定算法,分析了光钟输出频率噪声的产生机制;并以钙离子光钟为例,用蒙特卡洛方法在计算机上模拟了光钟运行,获得光钟的稳定度,且在同样参数下,与实验测得的稳定度进行了比较,结果表明两者具有较好的一致性。同时,通过修改光钟运行中的参数,研究了反馈周期内每个频率点探测离子次数N、增益系数g及激光的线性漂移对光钟稳定度的影响。结果表明光钟的秒稳对每个反馈周期内探测离子的次数N不敏感;且在g>0.45时,稳定度开始变差;此外,相对于钟激光的线性漂移,量子投影噪声对稳定度起主导作用。本研究提出的模拟光钟运行的方法能方便地应用到其他离子与原子光钟上,可对不同实验参数下光钟的稳定度进行评估。

基于Bell态纠缠交换的量子私密比较方案

提出了一种新的量子私密比较方案,该方案以Bell态为量子资源,在不泄露用户私密信息的前提下,利用Bell测量和纠缠变换实现对用户的信息相等与否的比对。第三方(TP)制备Bell态和诱饵单光子,在传送粒子过程中,TP插入诱饵单光子,通过经典信道的讨论保证了方案的安全性。用户双方不需要做任何幺正变换,只需执行Bell测量,随后将自己的私密信息加密后发送给第三方。第三方通过简单的计算就可以实现两比特经典信息的比对.整个过程中所涉及到的三方都无法得知他人的私密信息,只能得到比对结果.最后,由TP宣布比较结果。此外,也验证了方案的正确性。

从哥本哈根解释到退相干解释——量子力学解释的建构与比较

量子力学解释是对量子理论的扩展,必须体现量子理论语义上的一致性。正统的哥本哈根解释、最低限度的系综解释、本体论解释、多世界解释、模态解释、退相干解释,它们的解释力强弱与附加性要求不同,从两者之间的张力比较这些解释,既是整体科学知识的需要,也是理论语义上一致性的需要。

量子密钥分发误码协调算法分析

误码消除是量子密钥分发过程的关键技术之一。分析了奇偶-汉明单向函数纠错算法的原理,给出了对原始量子密钥进行误码协调的步骤及表达式,对这种算法的纠错能力进行了理论和实验分析。结果显示,当原始密钥误码率为11%时,利用该纠错技术能够完全消除误码,且最终密钥生成效率与密钥的原始误码率直接相关。

周期性信号之间的相位量子特征及其应用

针对周期性信号之间的普遍规律性,分析了等效鉴相频率和相位量子的概念.周期性信号除自身的变化规律外,周期性信号之间相互作用和联系的基础是相位量子,它揭示了周期性信号普遍联系的本质.实验证明相位量子是相互作用的周期性信号之间不可分割的基本个体,以相位量子为基础的测量、比对和控制能实现任意频率信号之间的直接相位比对.相位量子在主动型氢原子钟锁相环线路改造中简化了传输线路,减少了相位噪声引入,提高了性能。