Proof of the insecurity of quantum secret sharing based on the Smolin bound entangled states

This paper reconsiders carefully the possibility of using the Smolin bound entangled states as the carrier for sharing quantum secret. It finds that the process of quantum secret sharing based on Smolin states has insecurity though the Smolin state was reported to violate maximally the two-setting Bell-inequlity. The general proof is given.

Three-party quantum secret sharing of secure direct communication based on χ-type entangled states

Based on x-type entangled states and the two-step protocol [Deng F G, Long G L and Liu X S 2003 Phys. Rev. A 68 042317], a quantum secret sharing protocol of secure direct communication based on x-type entangled states ｜X00〉3214 is proposed. Using some interesting entanglement properties of this state, the agent entirety can directly obtain the secret message from the message sender only if they collaborate together. The security of the scheme is also discussed.

Cryptanalysis and improvement of a quantum secret sharing scheme based on χ-type entangled states

In the paper [2010 Chin. Phys. B 19 050306], Yang et al. put forward a novel three-party quantum secret sharing protocol of secure direct communication based on x-type entangled states, they claimed that the scheme is secure. However, in this paper, we study the security of the protocol and find that it is insecure. Applying intercept and resend attack, the agent Bob can obtain Alice＇s secret without the help from the other agent Charlie. In the end, we give our effective modification for its improvement.

Multiparty Quantum Secret Sharing via Introducing Auxiliary Particles Using a Pure Entangled State

We propose a new multiparty quantum secret sharing protocol via introducing auxiliary particles using a non-maximally entangled （pure） two-particle state without a Bell measurement. The communication parties utilize decoy particles tO check eavesdropping. After ensuring the security of the quantum channel, the sender encodes the secret message and transmits it to the receiver by using controlled-NOT operation and von Neumann measurement. If and only if all the agents agree to collaborate, they can read out the secret message.

Efficient quantum secret sharing scheme with two-particle entangled states

This paper proposes a protocol for multi-party quantum secret sharing utilizing four non-orthogonal two-particle entangled states following some ideas in the schemes proposed by Liu et al. （2006 Chin. Phys. Lett. 23 3148） and Zhang et al. （2009 Chin. Phys. B 18 2149） respectively. The theoretical efficiency for qubits of the new protocol is improved from 50% to approaching 100%. All the entangled states can be used for generating the private key except those used for the eavesdropping check. The validity of a probable attack called opaque cheat attack to this kind of protocols is considered in the paper for the first time.

Participant attack on quantum secret sharing based on entanglement swapping

The security of quantum secret sharing based on entanglement swapping is revisited and a participant attack is presented. In this attack two dishonest agents together can illegally recover the secret quantum state without the help of any other controller, and it will not be detected by any other users. Furthermore, by modifying the distribution process of particles and adding a detection step after each distribution process, we propose an improved protocol which can resist this kind of attack.

Eavesdropping on the Orderly-Encrypting Multiparty Quantum Secret Sharing Protocols

We discuss the security of the kind of multiparty quantum secret sharing protocols encrypting in series. It is secure against the eavesdroppers outside. However it is weak to withstand the attack of insider with a fake signal and cheating. An idiographic attack strategy is given based on the protocol. Furthermore, we conclude the key leak of the protocols and present a possible way to prevent the dishonest agents from stealing the secret.

A novel and efficient multiparty quantum secret sharing scheme using entangled states

We proposed a novel and efficient multiparty quantum secret sharing scheme using entangled state which in that the number of parties can be arbitrary large.The state which we used,has special properties that make our scheme simple and safe.The operations which are needed to recover secret message,are only exclusive-or addition and complement operation.Moreover it is shown that this scheme is secure against eavesdropping.Also this scheme provides the best quantum bit efficiency compared with some famous quantum secret sharing schemes.

Scheme for sharing classical information via tripartite entangled states

We investigate schemes for quantum secret sharing and quantum dense coding via tripartite entangled states. We present a scheme for sharing classical information via entanglement swapping using two tripartite entangled GHZ states. In order to throw light upon the security affairs of the quantum dense coding protocol, we also suggest a secure quantum dense coding scheme via W state by analogy with the theory of sharing information among involved users.

Probabilistic quantum teleportation of shared quantum secret

Very recently,Lee et al.proposed a secure quantum teleportation protocol to transfer shared quantum secret between multiple parties in a network[Phys.Rev.Lett.124060501(2020)].This quantum network is encoded with a maximally entangled GHZ state.In this paper,we consider a partially entangled GHZ state as the entanglement channel,where it can achieve,probabilistically,unity fidelity transfer of the state.Two kinds of strategies are given.One arises when an auxiliary particle is introduced and a general evolution at any receiver's location is then adopted.The other one involves performing a single generalized Bell-state measurement at the location of any sender.This could allow the receivers to recover the transmitted state with a certain probability,in which only the local Pauli operators are performed,instead of introducing an auxiliary particle.In addition,the successful probability is provided,which is determined by the degree of entanglement of the partially multipartite entangled state.Moreover,the proposed protocol is robust against the bit and phase flip noise.

利用N粒子纠缠态的量子秘密共享

为了高效实现多方之间的量子秘密共享,引入了一种纠缠度较高的N粒子纠缠态,并提出了利用该N粒子纠缠态在一方与(N-1)方之间形成共享秘密位串的方案.该方案在建立秘密位串的过程中,Alice对发送的粒子随机选择么正操作I和σx,并选择一部分粒子用于检测信道的安全;之后Alice根据(N-1)方选择的操作又选择了一部分粒子用于对参与者诚实度检测及信道安全检测.通过多次对窃听者的检测,很好地保证了信道的安全性及产生的秘密位串的可用性.最终在Alice及另外(N-1)方之间可形成n[1-(N-1)/2N-1]/6个共享秘密位.

两个基于四粒子纠缠态的量子秘密共享方案

分别基于四粒子Cluster态和一个非对称的四粒子纠缠态,提出两个量子秘密共享的方案,其中共享的秘密是未知的单粒子态。秘密的发送者需要对手中的粒子进行Bell基测量,协助者需要对手中的粒子进行测量或者实施幺正操作,最后接收者通过对手中的粒子进行相应的幺正变换或者受控非门操作,就可以重构原始秘密。通过分析表明,任何一个代理者在其他两方协助下是可以恢复秘密的,所以提出的方案是高效且安全可靠的。

利用最大真纠缠六方态共享经典秘密信息

纠缠是一种重要的量子信息资源,Bell态、GHZ态等纠缠态被广泛用于量子秘密共享中。Borras等人发现的最大真六方纠缠态在任意的双方割之间具有最大的纠缠值,已经被证明可用于量子隐形传态,并表现良好的性质。通过分析Borras态的结构,利用广义Schmidt分解工具,构造了一个具体的量子秘密共享协议:事先在Alice和4个代理之间共享一个Borras纠缠态,Alice拥有其中2个qubit,代理们分别拥有它的1个qubit,则Alice可在代理间共享2bit经典信息。

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。

可认证的多方量子秘密共享协议

利用Bell态的特性,提出一个可认证多方量子秘密共享协议.在协议中,秘密消息分发者通过局域幺正操作将两比特的经典秘密消息编码到量子载体中,并利用量子纠缠将其分割传输给n个代理人.每个代理人对手中的粒子进行Bell测量,以获得各自的子秘密.在消息重构过程中,当且仅当这n个代理人协作才能恢复出共享的秘密消息.同时,结合经典Hash函数对分发者和代理人的身份进行认证,实现双向认证的功能.最后,对协议的安全性和认证性进行了详细的讨论,表明所提方案在理论上是安全的.此外,本方案的实现只涉及到Bell态的制备和测量,这在现有的技术条件下是可行的.

基于四粒子cluster态的N位量子态秘密共享方案

为了实现N位量子态秘密共享,提出利用四粒子cluster态作为量子信道,cluster态虽然不是最大的纠缠态,但是有比最大纠缠态更强健的性质,通信者Alice通过添加辅助粒子,并对量子态进行五粒子联合测量,Bob(Charlie)对手中的粒子进行单粒子测量,并把结果和恢复量子态需要进行的操作告知Charlie(Bob),Charlie(Bob)按照从Bob(Charlie)处得到的信息对手中的粒子进行相应的操作,最后再根据需要,把量子态通过相应的量子线路得到所需要共享的量子态。安全性分析证明此方案是安全的。

基于Bell态的高效量子秘密共享

为提高协议在实验中的可操作性,提出了一个利用二粒子最大纠缠Bell态的量子秘密共享协议,其中发送方利用随机插入的正交单量子位,不仅可以有效地检测窃听行为,而且可以减少用于检测安全性的纠缠粒子,进而提高了纠缠粒子的利用率及产生密钥的效率;而接收方Bob和Charlie必须执行联合测量才能获得密钥,单独一方无法获得秘密信息.

基于四粒子纠缠态的量子秘密共享方案

基于两个不同的四粒子纠缠态分别提出了三方、四方量子秘密共享方案,其中采用的秘密信息是一个相同的未知两粒子纠缠态.在量子秘密共享方案中发送者对所拥有的粒子实施适当的Bell态(或GHZ态)测量,发送者和合作者通过经典通讯把测量结果告知信息接收者,接收者在其他合作者的协助下通过实施相应的量子操作完成对初始量子态信息的重构.对所提出的两个方案的安全性进行了讨论和比较,发现四方量子秘密共享方案更可靠。

基于纠缠交换(n-1，n)门限量子秘密共享方案

利用量子纠缠交换的思想,给出了一个(n-1,n)门限量子秘密共享方案(QSS).发送方利用局域幺正操作和纠缠交换,将子秘密分发给每个参与者.双方通过随机非对称使用消息模式和控制模式保证量子信道的安全.研究表明本方案是安全的.与采用Greenberger-Horne-Zeilinger(GHZ)纠缠态的量子秘密共享方案相比,本方案具有较高的效率;同时,其实现只涉及Bell态,在现有技术基础上是可行的.

一种无纠缠态的量子秘密共享协议

秘密共享是指将一个秘密按适当的方式进行隐藏或拆分,只有若干个参与者一同协作才能恢复该秘密,该技术在云计算领域中能够确保信息安全和数据保密。提出了一种不使用纠缠态的量子秘密共享协议,通过使用量子密码算法确保系统的安全性。相比其他的秘密共享协议,该协议具有以下优点:与传统的基于数论的秘密共享协议相比,本协议由于使用量子通信的技术,从而能够有效抵抗Shor算法攻击;相比其他的量子秘密共享协议,由于本协议没有使用量子纠缠态,在技术程度上更容易实现;如果存在攻击者或恶意的参与者,该协议能够在秘密恢复过程中迅速发现,避免恢复错误的秘密。