基于高维单粒子态的双向半量子安全直接通信协议

本文设计了一个基于高维单粒子态的双向半量子安全直接通信协议,该协议包括量子方Alice和经典方Bob,每个参与方可以同时接收和发送秘密信息.协议中的经典方Bob无需具备量子态检测能力,因此该协议在现有技术条件下更易实现.安全性分析表明:在不被合法通信者发现的情况下,截获重发、测量重发、篡改攻击以及纠缠攻击等常见攻击手段均无法获取秘密信息.此外,该协议利用高维单粒子态作为信息传输的载体,这有效提高了秘密信息的传输效率.     

基于单光子态自避错传输的量子安全直接通信协议

量子安全直接通信(Quantum secure direct communication,QSDC)是一种预先不需要建立共享秘钥而直接传输秘密信息的协议.针对信道中联合噪声的存在,提出一种基于单光子态自避错传输的量子安全直接通信协议.研究结果表明,该方案有效地避免了联合噪声对传输信息的影响,使接收方得到原未知量子态的成功率可趋近于100％,大大提高了量子态传输的保真度.该方案实验操作简单,有很高的学术研究和应用价值.     

单个N维量子系统的量子秘密共享

提出了一种单个N维量子系统的量子秘密共享方案.在该方案中，利用对Bennett和Brassard协议(BB84协议)中使用的两基四态扩展到多基多态，分发者对要共享的秘密采用多基多态编码，将被编码的单个N维量子系统发送给他的两个代理人之一，该代理人利用一个N维克隆机对接收到的粒子做幺正操作，然后把粒子发送给另一代理人.在得知最后一个代理人接收到该粒子之后，分发者告知两个代理人他所用的制备基，然后两个代理人分别对自己的系统进行测量并在合作之后获知分发者所发送的粒子的量子态.该方案的安全性基于量子不可克隆定理. 关键词： 量子秘密共享 多基多态编码 N维克隆机 量子不可克隆定理     

基于光量子态避错及容错传输的量子通信

量子通信以量子态为信息载体在远距离的通信各方之间传递信息,因此量子态的传输和远距离共享是量子通信的首要步骤.信道噪声不仅会影响通信效率还可能被窃听者利用从而威胁通信安全,对抗信道噪声是实现安全高效量子通信亟需解决的问题.本文介绍基于光量子态的两类对抗信道噪声的实用方法——量子态的避错传输和容错的量子通信,包括对抗噪声的基本原理和两种方法的代表性方案,并从资源消耗和可操作性的角度分析了方案的实用价值.     

单个N维量子系统的量子秘密共享

提出了一种单个N维量子系统的量子秘密共享方案.在该方案中,利用对Bennett和Brassard协议(BB84协议)中使用的两基四态扩展到多基多态,分发者对要共享的秘密采用多基多态编码,将被编码的单个N维量子系统发送给他的两个代理人之一,该代理人利用一个N维克隆机对接收到的粒子做幺正操作,然后把粒子发送给另一代理人.在得知最后一个代理人接收到该粒子之后,分发者告知两个代理人他所用的制备基,然后两个代理人分别对自己的系统进行测量并在合作之后获知分发者所发送的粒子的量子态.该方案的安全性基于量子不可克隆定理.另外该方案还具有信息量大效率高的特点.最后对该方案从两方扩展到N方进行了讨论.     

基于腔QED的无信息泄露量子对话(英文)

良好的安全性对量子保密通信协议而言是不可或缺的,但信息泄露已成为量子对话的一个严重安全威胁.为了解决信息泄露问题,利用腔QED中原子的演化规律提出一个基于腔QED的无信息泄露量子对话协议,利用腔QED中两个Bell态纠缠交换后的测量相关性来克服信息泄露问题.研究表明:该协议能够通过安全检测探测到外部窃听者的主动攻击,如截获-重发攻击、测量-重发攻击和纠缠-测量攻击;在每轮通信可以安全交换4比特秘密信息;对信息泄露问题和外部窃听者的主动攻击,都具备良好的安全性.     

光子两自由度超并行量子计算与超纠缠态操控

光子系统在量子信息处理和传输过程中有非常重要的应用. 譬如, 利用光子与原子(或人工原子)之间的相互作用, 可以完成信息的安全传输、存储和快速的并行计算处理等任务. 光子系统具有多个自由度, 如极化、空间模式、轨道角动量、时间-能量、频率等自由度. 光子系统的多个自由度可以同时应用于量子信息处理过程. 超并行量子计算利用光子系统多个自由度的光量子态同时进行量子并行计算, 使量子计算具有更强的并行性, 且需要的量子资源少, 更能抵抗光子数损耗等噪声的影响. 多个自由度同时存在纠缠的光子系统量子态称为超纠缠态, 它能够提高量子通信的容量与安全性, 辅助完成一些重要的量子通信任务. 在本综述中, 我们简要介绍了光子系统两自由度量子态在量子信息中的一些新应用, 包括超并行量子计算、超纠缠态分析、超纠缠浓缩和纯化三个部分.     

连续变量两组分非对称EPR导引交换特性

EPR(Einstein-Podolsky-Rosen)导引是一种特殊的量子现象,允许纠缠系统中的一方导引另一方,在单向的安全量子网络通信、量子秘密共享等量子协议中具有潜在的应用价值。基于连续变量两组分纠缠交换方案,对完成纠缠交换的两组分系统通过非对称调制和单端噪声引入两种方式,建立协方差矩阵,对最终输出的两组分纠缠量子态间的EPR导引特性进行分析和比较。研究量子系统中两组分EPR导引特性在两个模式间的变化情况,以及连续变量纠缠交换后两组分EPR导引参数随经典调制因子及噪声大小的变化关系,此理论研究结果为安全量子通信的实现提供了可行性参考。     

基于αη协议的量子数据流加密系统实际安全与性能分析

αη协议是一种利用量子噪声隐藏信息的随机加密协议. 通过求解高斯噪声信道中窃听者获取信息量的计算公式, 推导了该协议实际安全判据. 结果表明, 协议是否安全主要取决于信源量子态的平均光子数和密文符号数. 基于此, 计算了在光束分离攻击下两者的安全取值区间以及协议的有效通信距离.     

基于原子系综四波混频过程的量子信息协议

与经典体系相比,量子信息协议在大幅提高信息处理的安全性、保真度和容量方面具有巨大的优势。各种具有不同功能的量子信息协议已经被提出并实现。介绍了利用铷原子四波混频过程构建一套能兼容多种不同量子信息协议的多功能平台。基于这个平台可以实现并行9通道全光量子隐形传态,部分无实体量子态传输和最优N→M相干态量子克隆协议。更重要的是,部分无实体量子态传输协议可以同时连接全光量子隐形传态协议和最优1→M相干态量子克隆协议。这些量子信息协议在全光量子通信中具有潜在的应用。     

New Secure Quantum Dialogue Protocols over Collective Noisy Channels

Quantum dialogue (QD) belongs to two-way quantum secure direct communication. Particles are usually affected by noise during transmission in the quantum channel. In this paper, we propose three new robust quantum dialogue protocols immune to collective-amplitude-damping noise, collective-rotation noise and collective-dephasing noise, respectively. Based on logical qubits, both parties can communicate with each other directly without being disturbed by quantum channel noise. The security analysis shows that the proposed QD protocols can resist common outsider attacks without information leakage.

     

Information leakage resistant quantum dialogue against collective noise

In this paper,two information leakage resistant quantum dialogue(QD)protocols over a collective-noise channel are proposed.Decoherence-free subspace(DFS)is used to erase the influence from two kinds of collective noise,i.e.,collective-dephasing noise and collective-rotation noise,where each logical qubit is composed of two physical qubits and free from noise.In each of the two proposed protocols,the secret messages are encoded on the initial logical qubits via two composite unitary operations.Moreover,the single-photon measurements rather than the Bell-state measurements or the more complicated measurements are needed for decoding,making the two proposed protocols easier to implement.The initial state of each logical qubit is privately shared between the two authenticated users through the direct transmission of its auxiliary counterpart.Consequently,the information leakage problem is avoided in the two proposed protocols.Moreover,the detailed security analysis also shows that Eve’s several famous active attacks can be effectively overcome,such as the Trojan horse attack,the intercept-resend attack,the measure-resend attack,the entangle-measure attack and the correlation-elicitation(CE)attack.     

Fault tolerant channel-encrypting quantum dialogue against collective noise

In this paper,two fault tolerant channel-encrypting quantum dialogue(QD)protocols against collective noise are presented.One is against collective-dephasing noise,while the other is against collective-rotation noise.The decoherent-free states,each of which is composed of two physical qubits,act as traveling states combating collective noise.Einstein-Podolsky-Rosen pairs,which play the role of private quantum key,are securely shared between two participants over a collective-noise channel in advance.Through encryption and decryption with private quantum key,the initial state of each traveling two-photon logical qubit is privately shared between two participants.Due to quantum encryption sharing of the initial state of each traveling logical qubit,the issue of information leakage is overcome.The private quantum key can be repeatedly used after rotation as long as the rotation angle is properly chosen,making quantum resource economized.As a result,their information-theoretical efficiency is nearly up to 66.7%.The proposed QD protocols only need single-photon measurements rather than two-photon joint measurements for quantum measurements.Security analysis shows that an eavesdropper cannot obtain anything useful about secret messages during the dialogue process without being discovered.Furthermore,the proposed QD protocols can be implemented with current techniques in experiment.     

High-capacity quantum secure direct communication with two-photon six-qubit hyperentangled states

This study proposes the first high-capacity quantum secure direct communication(QSDC) with two-photon six-qubit hyperentangled Bell states in two longitudinal momentum and polarization degrees of freedom(DOFs) of photon pairs, which can be generated using two 0.5 mm-thick type-I β barium borate crystal slabs aligned one behind the other and an eight-hole screen. The secret message can be independently encoded on the photon pairs with 64 unitary operations in all three DOFs. This protocol has a higher capacity than previous QSDC protocols because each photon pair can carry 6 bits of information, not just 2 or 4 bits.Our QSDC protocol decreases the influence of decoherence from environment noise by exploiting the decoy photons to check the security of the transmission of the first photon sequence. Compared with two-way QSDC protocols, our QSDC protocol is immune to an attack by an eavesdropper using Trojan horse attack strategies because it is a one-way quantum communication.The QSDC protocol has good applications in the future quantum communication because of all these features.     

Secure quantum dialogue based on single-photon

In this paper a quantum dialogue scheme is proposed by using N batches of single photons. The same secret message is encoded on each batch of single photons by the sender with two different unitary operations, and then the N batches of single photons are sent to the receiver. After eavesdropping check, the message is encoded on the one remaining batch by the receiver. It is shown that the intercept-and-resend attack and coupling auxiliary modes attack can be resisted more efficiently, because the photons are sent only once in our quantum dialogue scheme.     

A Controller-Independent Quantum Dialogue Protocol with Four-Particle States

Controller-independent quantum dialogue (CIQD) is a significant topic in the research of quantum secure direct communication (QSDC). In this paper, we propose a new CIQD protocol with a special kind of four-particle entangled states. From our security analysis, it can be seen that the information leakage which is a serious problem in many CIQD protocols will be prevented in our protocol. Moreover, the presented protocol can resist many existing attacks, including intercept-and-resend attack, entangle-and-measure attack, fake entangled particles attack.

     

Quantum Dialogue with Authentication Based on Bell States

We propose an authenticated quantum dialogue protocol, which is based on a shared private quantum entangled channel. In this protocol, the EPR pairs are randomly prepared in one of the four Bell states for communication. By performing four Pauli operations on the shared EPR pairs to encode their shared authentication key and secret message, two legitimate users can implement mutual identity authentication and quantum dialogue without the help from the third party authenticator. Furthermore, due to the EPR pairs which are used for secure communication are utilized to implement authentication and the whole authentication process is included in the direct secure communication process, it does not require additional particles to realize authentication in this protocol. The updated authentication key provides the counterparts with a new authentication key for the next authentication and direct communication. Compared with other secure communication with authentication protocols, this one is more secure and efficient owing to the combination of authentication and direct communication. Security analysis shows that it is secure against the eavesdropping attack, the impersonation attack and the man-in-the-middle (MITM) attack.     

Quantum Secure Direct Communication by Using Three-Dimensional Hyperentanglement

We propose two schemes for realizing quantum secure direct communication (QSDC) by using a set of ordered two-photon three-dimensional hyperentangled states entangled in two degrees of freedom (DOFs) as quantum information channels. In the first scheme, the photons from Bob to Alice are transmitted only once. After insuring the security of the quantum channels, Bob encodes the secret message on his photons. Then Alice performs single-photon two-DOF Bell bases measurements on her photons. This scheme has better security than former QSDC protocols. In the second scheme, Bob transmits photons to Alice twice. After insuring the security of the quantum channels, Bob encodes the secret message on his photons. Then Alice performs two-photon Bell bases measurements on each DOF. The scheme has more information capacity than former QSDC protocols.     

Efficient and Secure Authenticated Quantum Dialogue Protocols over Collective-Noise Channels

Based on the deterministic secure quantum communication,we present a novel quantum dialogue protocol without information leakage over the collective noise channel.The logical qubits and four-qubit decoherence-free states are introduced for resisting against collective-dephasing noise,collective-rotation noise and all kinds of unitary collective noise,respectively.Compared with the existing similar protocols,the analyses on security and information-theoretical efficiency show that the proposed protocol is more secure and efficient.     

Cryptanalysis of Controlled Quantum Secure Direct Communication and Authentication Protocol Based on Five-Particle Cluster State and Quantum One-Time Pad

A new attack strategy, the so-called intercept-selectively-measure-resend attack is put forward. It shows that there are some security issues in the controlled quantum secure direct communication (CQSDC) and authentication protocol based on five-particle cluster states and quantum one-time pad. Firstly, an eavesdropper (Eve) can use this attack to eavesdrop on 0.656 bit of every bit of the identity string of the receiver and 1.406 bits of every couple of the corresponding bits of the secret message without being detected. Also, she can eavesdrop on 0.311 bit of every bit of the identity string of the controller. Secondly, the receiver can also take this attack to obtain 1.311 bits of every couple of the corresponding bits of the secret message without the permission of the controller, which is not allowed in the CQSDC protocols. In fact, there is another security issue in this protocol, that is, one half of the information about the secret is leaked out unconsciously. In addition, an alternative attack strategy which is called as the selective-CNOT-operation attack strategy to attack this protocol is discussed.