Semi-quantum protocol for deterministic secure quantum communication using Bell states

Based on Bell states, this paper proposes a semi-quantum protocol enabling the limited semi-quantum or “classical” user Bob to transmit the secret message to a fully quantum Alice directly. A classical user is restricted to measure, prepare, reorder and send quantum states only in the classical basis \( \{ \left| 0 \right\rangle ,\left| 1 \right\rangle \} \). The protocol must rely on the quantum Alice to produce Bell states, perform Bell basis measurement and store qubits, but the classical party Bob does not require quantum memory. Security and efficiency of the proposed schemes have been discussed. The analysis results show that the protocol is secure against some eavesdropping attacks and the qubit efficiency of the protocol is higher than the other related semi-quantum protocols.     

Hierarchical quantum information splitting with eight-qubit cluster states

In the paper, a scheme is proposed for hierarchical quantum information splitting with an unknown eight-qubit cluster state. The Boss Alice wants to distribute a quantum secret to seven distant agents who are divided into two grades. Three agents are in the upper grade and four agents are in the lower grade. Every agent of the upper grade only needs the collaboration of three of the other six agents to get the secret, but all the agents of the lower grade need the collaboration of all the other six agents. In other words, different agents in different grades have different authorities to recover Boss’ secret. And the agent in upper grade is more powerful than the one in the lower grades which needs more information to recover the secret.     

Joint remote state preparation of arbitrary two-particle states via GHZ-type states

The protocols for joint remote preparation of an arbitrary two-particle pure state from a spatially separated multi-sender to one receiver are presented in this paper. We first consider the situation of two sender and demonstrate a flexible deterministic joint remote state preparation compared with previous probabilistic schemes. And then generalize the protocol to multi-sender and show that by only adding some classical communication the success probability of preparation can be increased to four times. Finally, using a proper positive operator-valued measure instead of usual projective measurement, we present a new scheme via two non-maximally entangled states. It is shown that our schemes are generalizations of the usual standard joint remote state preparation scheme and more suitable for real experiments with requirements of only Pauli operations.     

Quantum information splitting of an arbitrary three-qubit state by using two four-qubit cluster states

A new application of the four-qubit cluster state is investigated for quantum information splitting (QIS) of an arbitrary three-qubit state. Muralidharan and Panigrahi (Phys Rev A 78:062333, 2008) argued that a four-qubit cluster state is impossible for QIS of an arbitrary two-qubit state. In this paper, we demonstrate that two four-qubit cluster states can be used to realize the deterministic QIS of an arbitrary three-qubit state by performing only the Bell-state measurements. Our scheme considered here is secure against certain eavesdropping attacks.     

基于W态的高效量子信息拆分方案

为提高基于W态的量子通信方案的效率,提出了一种新的基于W态的量子信息拆分(QIS)方案。该方案中,秘密分发者通过局域操作将经典信息编码在量子比特上,并在分发的量子比特中随机插入非正交态粒子进行检测窃听,参与者只需进行3粒子投影测量即可恢复秘密。方案使参与者能够利用1个W态直接共享2比特经典信息,并能够抵御截获-测量、截获-重发和纠缠附加粒子攻击,安全性得以保证。该方案效率较高, 理论上其量子比特效率为67%。     

属性频率划分和信息熵离散化的决策树算法

决策树是数据挖掘任务中分类的常用方法。在构造决策树的过程中,节点划分属性选择的度量直接影响决策树分类的效果。基于粗糙集的属性频率函数方法度量属性重要性,并用于分枝划分属性的选择和决策树的预剪枝,提出一种决策树学习算法。同时,为了能处理数值型属性,利用数据集的统计性质为启发式知识,提出了一种改进的数值型属性信息熵离散化算法。实验结果表明,新的离散化方法计算效率有明显提高,新的决策树算法与基于信息熵的决策树算法相比较,结构简单,且能有效提高分类效果。     

Multi-qudit information splitting with multiple controllers

In this paper, we first present a five-party scheme for sharing a single-qutrit state by using GHZ states as the quantum channel. Any one of the agents has the access to reconstruct the original state if other controlling agents cooperate with him. We also sketch the generation of five-party scheme to the case of multi-qudit states and multiple participants by a composite channel composed of generalized Bell states and GHZ states. In our scheme, the physical operations, especially for the controllers and the final receiver, are considerably reduced. It also demonstrates a high degree of symmetry and provides a useful inspiration for implementing hierarchical quantum information splitting.     

Beam splitting and entanglement generation: excited coherent states

We study the mathematical properties of the excited coherent states, which are obtained through actions of a photon creation operator of the mode optical field on its corresponding coherent state, by analyzing the minimal set of Klauder’s coherent states. Using linear entropy as a measure of entanglement, we investigate in detail the entanglement generated via a beam splitter when an excited coherent state is injected on one input mode and vacuum state is injected on the other one. Finally, we examine the physical properties of the excited coherent states through the Mandel’s parameter and the Wehrl entropy and we give the correlation between these parameters and the entanglement of the output state.     

Efficient quantum dialogue using entangled states and entanglement swapping without information leakage

We propose a novel quantum dialogue protocol by using the generalized Bell states and entanglement swapping. In the protocol, a sequence of ordered two-qutrit entangled states acts as quantum information channel for exchanging secret messages directly and simultaneously. Besides, a secret key string is shared between the communicants to overcome information leakage. Different from those previous information leakage-resistant quantum dialogue protocols, the particles, composed of one of each pair of entangled states, are transmitted only one time in the proposed protocol. Security analysis shows that our protocol can overcome information leakage and resist several well-known attacks. Moreover, the efficiency of our scheme is acceptable.     

基于量子信息拆分的多人验证签名方案

提出了一种利用W态实现的对经典信息的多人验证签名方案。协议基于量子信息拆分原理,将签名信息拆分成两部分,由一次一密算法和量子单向函数加密签名信息,两个验证人验证签名。方案满足经典安全性要求的不可伪造性和不可否认性,同时也能够抵御量子攻击策略当中的截获重发攻击和纠缠附加粒子攻击,相较其他量子签名方案,效率和安全性都有所提高。     

Quantum state sharing of an arbitrary four-qubit GHZ-type state by using a four-qubit cluster state

We demonstrate that a four-qubit cluster state can be used to realize the deterministic quantum state sharing (QSTS) of an arbitrary four-qubit GHZ-type state among three parties by introducing three ancillary qubits and performing three controlled-NOT operations. In our scheme, any one of the two agents has the ability to reconstruct the original state if he/she collaborates with the other one, whilst individual agent obtains no information.     

基于量子委托计算模式的半量子密钥协商

为降低量子设备的成本,更好地执行量子计算,提出基于量子委托计算模式的多方半量子密钥协商协议。引入量子委托计算模式,将酉操作、Bell测量等复杂量子操作委托到量子中心进行,而参与者仅需具备访问量子信道与制备单光子的简单能力。为防止密钥信息被量子中心以及外部窃听者窃取,采用在目标量子态中插入混淆单光子的混淆策略来保证目标量子态的隐私性。分析结果表明,与其他量子密钥协商协议相比,参与者所需的量子能力显著降低,从而提升了协议的实际可行性。     

An optimized quantum information splitting scheme with multiple controllers

We propose an efficient scheme for splitting multi-qudit information with cooperative control of multiple agents. Each controller is assigned one controlling qudit, and he can monitor the state sharing of all multi-qudit information. Compared with the existing schemes, our scheme requires less resource consumption and approaches higher communication efficiency. In addition, our proposal involves only generalized Bell-state measurement, single-qudit measurement, one-qudit gates and a unitary-reduction operation, which makes it flexible and achievable for physical implementation.     

基于贝尔态的半量子安全直接通信协议

针对量子通信网络构建成本昂贵且效率低下的问题,基于贝尔态粒子和半量子理论,提出了一种易于实现的量子安全直接通信模型。首先,量子态的制备、Bell基测量等复杂操作交由拥有全部量子能力的服务端完成,用户端只需完成投影测量或者直接反射两种简单操作;其次,通信双方传输秘密信息前建立的量子信道以及提前共享的安全密钥,可以严格保障秘密信息不被泄露;最后,通过设计的编码规则,使得协议只使用较少量子资源就完成高效的秘密信息直接传输。通过计算可得,提出的量子安全直接通信模型粒子传输效率达到7.69%,安全模型分析表明了提出的通信模型在各种常见的攻击策略下都是安全可靠的。     

Quantum information splitting of an arbitrary three-qubit state by using a genuinely entangled five-qubit state and a Bell-state

A new application of the genuinely entangled five-qubit state introduced by Brown et al. (J Phys A 38(5), 1119–1131, 2005) is investigated for quantum information splitting (QIS) of an arbitrary three-qubit state. We demonstrate that such a genuine five-qubit entangled state and a Bell-state can be used to realize the deterministic QIS of an arbitrary three-qubit state by performing the Bell-state measurements and single qubit measurement. The presented protocol is showed to be secure against certain eavesdropping attacks.     

Cryptographic techniques of strategic data splitting and secure information management

This publication presents techniques for classifying strategic information, namely financial figures which make it possible to determine the standing of an enterprise or an organisation. These techniques of classifying (hiding) strategic information will be presented based on their application to problems of securely storing data of special significance, i.e. cryptographic information sharing protocols. What will be innovative will be the use of cryptographic information sharing protocols in cognitive systems for data analysis. This class of systems will be discussed based on systems for the semantic analysis of ratio data used to analyse liquidity indicators.     

Cryptanalysis and improvement of efficient quantum dialogue using entangled states and entanglement swapping without information leakage

The novel quantum dialogue (QD) protocol by using the three-dimensional Bell states and entanglement swapping (Wang et al. in Quantum Inf Process 15(6):2593–2603, 2016) is analyzed. It is shown that there is the information leakage problem in this QD protocol. To be specific, one quarter information of the secret messages exchanged is leaked out unconsciously. Afterward, it is improved to a truly secure one without information leakage. Besides, the security of the improved QD protocol is analyzed in detail. It is shown that the improved QD protocol has some obvious features compared with the original one.     

Entropy defect and information for two quantum states

An explicit formula is obtained for the entropy defect and the (maximum) information for an ensemble of two pure quantum states; an optimal basis is found, that is, an optimal measurement procedure which enables one to obtain the maximum information. Some results are also presented for the case of two mixed states, described by second-order density matrices (for example, spin polarization matrices). It is shown that in the case of two states the optimal measurement is a direct von Neumann measurement performed in the subspace of the two states.     

使用新的码字分割方法的快速LBG算法

针对LBG算法中初始码书生成存在盲目性的问题,提出了一种基于训练向量集合分量之间的相关性进行码向量分割的方法。在迭代过程,记录每一个码向量所映射的训练向量子集;生成新的初始码书时,首先计算被分割码向量所映射的训练子集的第一个分量与其他各分量之间的协方差;根据协方差来分割相应的码向量。实验表明,应用新的码向量分割机制后,LBG算法中的迭代次数和运行时间减少了约10%左右。     

Classification using information

Let be a set of functions. A classifier for is a way of telling, given a function f, if f is in . We will define this notion formally. We will then modify our definition in three ways: (1) allow the classifier to ask questions to an oracle A (thus increasing the classifiers computational power), (2) allow the classifier to ask questions about f (thus increasing the classifiers information access), and (3) restrict the number of times the classifier can change its mind (thus decreasing the classifiers information access). By varying these parameters we will gain a better understanding of the contrast between computational power and informational access. We have determined exactly (1) which sets are classifiable (theorem 3.6), (2) which sets are classifiable with queries to some oracle (theorem 3.2), (3) which sets are classifiable with queries to some oracle and queries about f (theorem 5.2), and (4) which sets are classifiable with queries to some oracle, queries about f and a bounded number of mindchanges (theorem 5.2). The last two items involve the Borel hierarchy. This revised version was published online in June 2006 with corrections to the Cover Date.