多跳环形量子网络密钥共享协议的研究

为有效解决量子网络的安全问题,提出了多跳环形量子网络的量子密钥共享协议.该协议在由2N+1个量子节点组成的环形网络中通过EPR对传输密钥.量子节点t0利用CONT门、H门操作,将密钥通过t1传递给t2,再多跳的依次传递给量子节点t4,…,t2通过t3…t2N-1,最终将共享信息传递给最后的量子节点.该协议利用现有的手段可以实现.     

基于Bell态的量子秘密共享协议

为提高效率,提出了一种直接共享经典信息的量子秘密共享协议。协议利用Pauli矩阵的特殊性质将经典信息编码在Bell态上实现秘密共享,为了检测是否存在窃听者,通过随机插入诱骗光子的方法确保传输的安全。分析表明该协议是安全的,效率可以达到1个Be11态共享2 bit经典信息。     

9-量子团簇态信道的非对称双向量子信息传输

利用一个9-量子团簇态为信道,分别提出了三个关于二量子态和三量子态的双向量子信息传输协议。在第一个协议中,Alice能把三量子a1、a2和a3的未知态传送给Bob,Bob能把二量子b1和b2的未知态传送给Alice。Alice采用特殊三粒子态测量基,使得方案简化了一半。在第二个协议中,Alice在远方的Bob处制备三粒子a1、a2和a3的已知态,同时Bob也能在Alice处制备二量子b1和b2的已知态。由于他们充分利用了前馈测量策略,制备任务能够完美完成。在第三个协议中,利用前两个协议的优点,Alice能成功将三量子a1、a2和a3的未知态传送给Bob,Bob也完美地在Alice处制备二量子b1和b2的已知态。     

一种量子密钥分发中的身份认证协议

假设两通信用户共享一初始比特串K,提出一种新的思想,即共享的K不直接用来认证,而是先经过一个简单算法将其转换为一个较长的K′,在对K′作适当处理后再用来认证。在此基础上几乎所有的量子密钥分发协议都可以同时进行身份认证。作为例证,还提出一个新的基于非正交纠缠态的量子身份认证(QKA)协议,该协议能同时进行量子密钥分发(QKD),分析表明此协议比传统的QKD协议更简单、安全。     

基于团簇态的量子秘密共享方案

提出了一个基于团簇态的量子秘密共享方案,发送者通过Pauli操作将经典秘密信息编码在团簇态上进行分发,接收者通过联合测量实现秘密共享。协议插入EPR对作为诱骗态以防止窃听,通过安全性分析证明本协议是安全的,可以抵抗截获-测量、截获-重发和纠缠-测量攻击。此外,协议传输一个四粒子团簇态可以共享四个经典比特信息,量子比特效率达到100%。     

一种基于物理-社交感知和支付激励的D2D多播内容共享策略

面向大规模用户的多媒体业务尤其是在线视频业务正呈现爆炸式发展的态势,D2D(Device-to-Device)多播内容共享技术被认为是一种可以有效应对大规模用户海量数据分发的关键技术。但目前关于D2D多播内容共享的研究多集中在如何提高系统的能量有效性上,对于系统数据速率和的研究不多,而系统数据速率和是反映系统能否高效分发内容的一个重要指标。为了建立一个贴近实际场景的用户模型并实现高效内容分发以减轻基站负担并提高资源(频谱和能量)利用效率,文中提出一种基于物理-社交感知和支付激励的D2D多播内容共享策略。首先,根据实际场景的限制对D2D多播通信进行建模,把模型的应用场景扩大到人流集中的高速内容共享的“热点”地区和不利于基站直接传输数据(如抗震救灾时)的大规模搜救行动的“盲点”地区。随后,以有效降低基站负载和应对海量数据分发为目标,提出以多约束条件下系统等效数据速率和为目标函数的优化问题,通过引入支付机制激励用户作为簇头为其他用户提供共享内容,通过引入基于兴趣相似度的社交关系来提高资源利用效率并降低用户支付代价。最后,提出簇头选择-簇形成算法来求解上述问题。在簇头选择算法中,在考虑用户数据速率阈值限制的同时,引入基于用户兴趣相似度的社交关系;在簇形成算法中,采用了一种增益定义与“联盟”内涵高度契合的集中控制式的联盟形成博弈模型。仿真结果表明,与相关同类策略相比,所提策略在等效数据速率和与实际数据速率和两项指标上的性能得到了显著提高,同时证明了该策略适合大规模用户的网络。     

一种无线网络量子密钥分配协议

论文在BB84协议基础上提出了一个无线网络量子密钥协议,该协议利用一条具有回路的量子信道传送信息并设计一种新的编码方式,使光子利用效率达到100％,密钥分配效率是BB84量子密钥分配协议的两倍或更高,并且该协议不需要容易被攻击的经典信道,更适用于无线网络.该协议通过预共享密钥方法进行身份认证,避免了攻击者跳过身份认证直接发送密钥的弊端,采用消息摘要的方法验证消息是否被篡改或窃听,由于消息摘要使用了预共享密钥进行一次一密加密,攻击者无法篡改,从而保证安全.     

认知无线电网络MAC层协议研究

认知网络按照一定的准则划分为若干个簇,簇内共享一条信道用于交换控制信息,这种以分簇的方式实现按区域共享信道是认知无线电MAC层频谱共享问题的解决方法之一.为了使分簇结构更加有效的工作,本文提出了一种针对分簇结构的MAC层协议.在该协议中,信道接入时间被划分成一系列的超级帧,超级帧的各个时段均对应簇节点的具体操作,以此支撑簇结构稳健地应对主用户行为.仿真结果表明,本文提出的MAC协议在中高网络负载情况下能获得较高的网络吞吐量以及较低的传输时延.     

三态纠缠的可控的量子秘密共享协议

提出由3个节点组成的星型量子网络中,基于三态纠缠的可控的量子秘密共享协议。在协议中,3个节点S₁、S₂、S₃共享2N个GHZ-like states,发送编码序列,利用可控制的状态参量α,将测量结果的联合计算共享密钥。理论分析证明,该协议对于外在的窃听者Eve和内在的窃听者都具有很高的安全性。如果存在窃听者,则必然发现,从而保证了共享量子密钥的安全性。     

能量搜集充电的设备到设备通信功率分配方案

主要研究多个能量搜集充电的设备到设备(D2D)用户非正交复用一个蜂窝用户信道资源时的功率分配问题。在保障蜂窝用户的服务质量前提下,建立了一个最大化能量搜集充电的D2D用户的传输速率问题。由于该问题是一个非凸规划问题,提出一种低复杂度的凸近似算法,并得到该问题的一个紧下界可行解。最后,通过仿真分析得出该算法能够逼近最优传输速率,为多个能量搜集充电的D2D对与一个蜂窝用户共享链路的场景提供有效的功率分配方案。     

Quantum authencryption: one-step authenticated quantum secure direct communications for off-line communicants

This work proposes a new direction in quantum cryptography called quantum authencryption. Quantum authencryption (QA), a new term to distinguish from authenticated quantum secure direct communications, is used to describe the technique of combining quantum encryption and quantum authentication into one process for off-line communicants. QA provides a new way of quantum communications without the presence of a receiver on line, and thus makes many applications depending on secure one-way quantum communications, such as quantum E-mail systems, possible. An example protocol using single photons and one-way hash functions is presented to realize the requirements on QA.     

An economic and feasible Quantum Sealed-bid Auction protocol

We present an economic and feasible Quantum Sealed-bid Auction protocol using quantum secure direct communication based on single photons in both the polarization and the spatial-mode degrees of freedom, where each single photon can carry two bits of classical information. Compared with previous protocols, our protocol has higher efficiency. In addition, we propose a secure post-confirmation mechanism without quantum entanglement to guarantee the security and the fairness of the auction.     

VENUS: A Geometrical Representation for Quantum State Visualization

Visualizations have played a crucial role in helping quantum computing users explore quantum states in various quantum computing applications. Among them, Bloch Sphere is the widely-used visualization for showing quantum states, which leverages angles to represent quantum amplitudes. However, it cannot support the visualization of quantum entanglement and superposition, the two essential properties of quantum computing. To address this issue, we propose VENUS, a novel visualization for quantum state representation. By explicitly correlating 2D geometric shapes based on the math foundation of quantum computing characteristics, VENUS effectively represents quantum amplitudes of both the single qubit and two qubits for quantum entanglement. Also, we use multiple coordinated semicircles to naturally encode probability distribution, making the quantum superposition intuitive to analyze. We conducted two well-designed case studies and an in-depth expert interview to evaluate the usefulness and effectiveness of VENUS. The result shows that VENUS can effectively facilitate the exploration of quantum states for the single qubit and two qubits.     

基于GHZ的多用户量子网络密钥传输协议

提出了在一个多用户量子网络中，基于3个粒子最大纠缠态GHZ的密钥传输协议。这个量子密钥传输协议在通信节点和控制中心之间通过多个GHZ对构建安全的密码分配系统。与经典的量子密码术相比，理论分析证明，如果存在窃听者Eve，则他为获得有用的信息会不断向网络引入错误。该网络的节点和控制中心必然发现Eve，从而保证了网络密钥的安全性。     

基于Smolin states量子网络安全线路评估

提出在由4个节点组成的量子网络中,基于Smolin state的量子网络安全线路评估传输协议。在量子网络中,有一个主节点、三个从节点,共享Smolin state态,随机的发送编码序列,利用测量结果的联合计算,来保证协议的安全性。理论分析证明,该协议对于三个窃听者、两个窃听者、一个窃听者都具有很高的安全性。如果存在窃听者存在,必然发现,从而保证了量子网络线路的安全性。     

Bidirectional controlled quantum teleportation and secure direct communication using five-qubit entangled state

A scheme is presented to implement bidirectional controlled quantum teleportation (QT) by using a five-qubit entangled state as a quantum channel, where Alice may transmit an arbitrary single qubit state called qubit A to Bob and at the same time, Bob may also transmit an arbitrary single qubit state called qubit B to Alice via the control of the supervisor Charlie. Based on our channel, we explicitly show how the bidirectional controlled QT protocol works. By using this bidirectional controlled teleportation, espcially, a bidirectional controlled quantum secure direct communication (QSDC) protocol, i.e., the so-called controlled quantum dialogue, is further investigated. Under the situation of insuring the security of the quantum channel, Alice (Bob) encodes a secret message directly on a sequence of qubit states and transmits them to Bob (Alice) supervised by Charlie. Especially, the qubits carrying the secret message do not need to be transmitted in quantum channel. At last, we show this QSDC scheme may be determinate and secure.     

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.     

Quantum network coding for multi-unicast problem based on 2D and 3D cluster states

We mainly consider quantum multi-unicast problem over directed acyclic network, where each source wishes to transmit an independent message to its target via bottleneck channel. Taking the advantage of global entanglement state 2D and 3D cluster states, these problems can be solved efficiently. At first, a universal scheme for the generation of resource states among distant communication nodes is provided. The corresponding between cluster and bigraph leads to a constant temporal resource cost. Furthermore, a new approach based on stabilizer formalism to analyze the solvability of several underlying quantum multi-unicast networks is presented. It is found that the solvability closely depends on the choice of stabilizer generators for a given cluster state. And then, with the designed measurement basis and parallel measurement on intermediate nodes, we propose optimal protocols for these multi-unicast sessions. Also, the analysis reveals that the resource consumption involving spatial resources, operational resources and temporal resources mostly reach the lower bounds.