Efficient multiparty quantum key agreement protocol based on commutative encryption

A secure multiparty quantum key agreement protocol using single-qubit states is proposed. The agreement key is computed by performing exclusive-OR operation on all the participants’ secret keys. Based on the commutative property of the commutative encryption, the exclusive-OR operation can be performed on the plaintext in the encrypted state without decrypting it. Thus, it not only protects the final shared key, but also reduces the complexity of the computation. The efficiency of the proposed protocol, compared with previous multiparty QKA protocols, is also improved. In the presented protocol, entanglement states, joint measurement and even the unitary operations are not needed, and only rotation operations and single-state measurement are required, which are easier to be realized with current technology.     

Multiparty quantum key agreement with single particles

Two conditions must be satisfied in a secure quantum key agreement (QKA) protocol: (1) outside eavesdroppers cannot gain the generated key without introducing any error; (2) the generated key cannot be determined by any non-trivial subset of the participants. That is, a secure QKA protocol can not only prevent the outside attackers from stealing the key, but also resist the attack from inside participants, i.e. some dishonest participants determine the key alone by illegal means. How to resist participant attack is an aporia in the design of QKA protocols, especially the multi-party ones. In this paper we present the first secure multiparty QKA protocol against both outside and participant attacks. Further more, we have proved its security in detail.     

Multiparty quantum key agreement protocol based on locally indistinguishable orthogonal product states

Based on locally indistinguishable orthogonal product states, we propose a novel multiparty quantum key agreement (QKA) protocol. In this protocol, the private key information of each party is encoded as some orthogonal product states that cannot be perfectly distinguished by local operations and classical communications. To ensure the security of the protocol with small amount of decoy particles, the different particles of each product state are transmitted separately. This protocol not only can make each participant fairly negotiate a shared key, but also can avoid information leakage in the maximum extent. We give a detailed security proof of this protocol. From comparison result with the existing QKA protocols, we can know that the new protocol is more efficient.     

基于GHZ态的无酉操作多方量子秘密共享方案

为了简化多方量子秘密共享协议,利用Greenberger-Horne-Zeilinger（GHZ）态和互补基特性,提出了一种简单高效的多方量子秘密共享方案。该方案无需进行任何酉操作,发送方和多个接收方之间只需一次量子通信,并使用互补基进行测量即可完成信道安全检测和秘密共享。除去少量用于检测量子信道安全的粒子,其余每个GHZ态粒子共享一个比特的经典信息。安全性分析表明该方案是安全可靠的。     

Three-party remote state preparation schemes based on entanglement

By exploiting the entanglement correlation in quantum mechanics, two three-party remote state preparation (RSP) schemes are proposed. One is three-party remote preparation of a single-particle quantum state, and the other is three-party remote preparation of a two-particle entangled state. In the proposed schemes, the sender Alice knows the quantum states to be prepared, while the receivers Bob and Charlie do not know the quantum states; Alice performs measurement and unitary operations on her own particles with two three-particle GHZ states as the quantum channel. According to Alice’s measurement results, Bob and Charlie measure their own particles on the corresponding quantum measurement bases and perform unitary operations on the corresponding particles to reconstruct the quantum states, respectively. Compared with multiparty joint remote preparation and two-party RSP of a quantum state, the proposed schemes realize quantum multicast communication successfully, which enables Bob and Charlie to obtain the prepared quantum states simultaneously in the case of just knowing Alice’s measurement results, while Bob and Charlie do not know each other’s prepared quantum states. It is shown that only three classical bits are required for the two proposed RSP schemes when Bob and Alice introduce an auxiliary particle, respectively, and the proposed schemes are secure after the quantum channel authentication.     

Multi-party quantum key agreement protocol secure against collusion attacks

The fairness of a secure multi-party quantum key agreement (MQKA) protocol requires that all involved parties are entirely peer entities and can equally influence the outcome of the protocol to establish a shared key wherein no one can decide the shared key alone. However, it is found that parts of the existing MQKA protocols are sensitive to collusion attacks, i.e., some of the dishonest participants can collaborate to predetermine the final key without being detected. In this paper, a multi-party QKA protocol resisting collusion attacks is proposed. Different from previous QKA protocol resisting \(N-1\) coconspirators or resisting 1 coconspirators, we investigate the general circle-type MQKA protocol which can be secure against t dishonest participants’ cooperation. Here, \(t < N\). We hope the results of the presented paper will be helpful for further research on fair MQKA protocols.     

异构家庭网络中融合量子信息技术的安全通信协议

随着量子信息技术与家庭网络技术日益紧密结合,采用量子密钥确保家庭网络的通信安全已经成为大势所趋.针对目前数字家庭通信网络的安全日益复杂和多样化的问题,提出了异构家庭网络中融合量子信息技术的安全通信协议,智能终端设备、家庭网关、业务管理平台内的服务器共享量子GHZ 态,根据GHZ 三重态的内在特性,从而实现业务管理平台内的服务器对智能终端设备的合法性访问和数据处理.该协议利用现有手段可以实现.     

Multiparty quantum sealed-bid auction using single photons as message carrier

In this study, a novel multiparty quantum sealed-bid auction protocol using the single photons as the message carrier of bids is proposed, followed by an example of three-party auction. Compared with those protocols based on the entangled states (GHZ state, EPR pairs, etc.), the present protocol is more economic and feasible within present technology. In order to guarantee the security and the fairness of the auction, the decoy photon checking technique and an improved post-confirmation mechanism with EPR pairs are introduced, respectively.     

Protocols of quantum key agreement solely using Bell states and Bell measurement

Two protocols of quantum key agreement (QKA) that solely use Bell state and Bell measurement are proposed. The first protocol of QKA proposed here is designed for two-party QKA, whereas the second protocol is designed for multi-party QKA. The proposed protocols are also generalized to implement QKA using a set of multi-partite entangled states (e.g., 4-qubit cluster state and \(\Omega \) state). Security of these protocols arises from the monogamy of entanglement. This is in contrast to the existing protocols of QKA where security arises from the use of non-orthogonal state (non-commutativity principle). Further, it is shown that all the quantum systems that are useful for implementation of quantum dialogue and most of the protocols of secure direct quantum communication can be modified to implement protocols of QKA.     

Cryptanalysis of a multi-party quantum key agreement protocol with single particles

Recently, Sun et al. (Quantum Inf Process 12:3411–3420, 2013) presented an efficient multi-party quantum key agreement (QKA) protocol by employing single particles and unitary operations. The aim of this protocol is to fairly and securely negotiate a secret session key among \(N\) parties with a high qubit efficiency. In addition, the authors claimed that no participant can learn anything more than his/her prescribed output in this protocol, i.e., the sub-secret keys of the participants can be kept secret during the protocol. However, here we point out that the sub-secret of a participant in Sun et al.’s protocol can be eavesdropped by the two participants next to him/her. Moreover, a certain number of dishonest participants can fully determine the final shared key in this protocol. Finally, we discuss the factors that should be considered when designing a really fair and secure QKA protocol.     

基于部分纠缠态的量子安全直接通信协议

提出一种新的带认证的三方量子安全直接通信协议。该方案利用共享的三粒子部分纠缠态和CNOT门来编码和译码,两方可同时向第三方传递秘密消息,共享的部分纠缠态可重复使用。在理想信道下,协议对于非相干攻击是安全的。该方案通过认证可以验证客户端身份的合法性,部分纠缠态在实际中容易制备和保存,能够实现两方同时跟第三方直接通信。     

Threshold quantum secret sharing between multiparty and multiparty using Greenberger–Horne–Zeilinger state

We propose a (t, m)?(s, n) threshold quantum secret sharing protocol between multiparty (m members in group 1) and multiparty (n members in group 2) using a sequence of Greenberger–Horne–Zeilinger (GHZ) states, which is useful and efficient when the parties of communication are not all present. In the protocol, Alice prepares a sequence of GHZ states in one of the eight different states and sends the last two particles to the first agent while other members encode their information on the sequence via unitary transformations. Finally the last member in group 2 measures the qubits. It is shown that this scheme is safe.     

The general theory of three-party quantum secret sharing protocols over phase-damping channels

The general theory of three-party QSS protocols with the noisy quantum channels is discussed. When the particles are transmitted through the noisy quantum channels, the initial pure three-qubit tripartite entangled states would be changed into mixed states. We analyze the security of QSS protocols with the different kinds of three-qubit tripartite entangled states under phase-damping channels and figure out, for different kinds of initial states, the successful probabilities that Alice’s secret can be recovered by legal agents are different. Comparing with one recent QSS protocol based on GHZ states, our scheme is secure, and has a little smaller key rate than that of the recent protocol.     

Two-party quantum key agreement with four-qubit cluster states

Based on four-qubit cluster states, we present a two-party quantum key agreement (QKA) scheme using unitary operations. In this scheme, two participants perform the unitary operation on the different photon of the same cluster state, which guarantees that each party contributes equally to the agreement key. By measuring each cluster state and decoding, these two participants can generate a four-bit classical key without the exchange of classical bits between them. Compared with other existed two-party QKA protocols, our scheme is efficient. Security analysis shows that our protocol is secure against both participant and outsider attack.     

多用户网络量子密码术的改进

针对经典的利用EPR粒子纠缠态互换的量子密钥传输协议存在的问题,它提出了一个在多用户传输网络中,基于3个粒子的最大纠缠态GHZ安全的量子密钥传输协议.改进的量子密钥传输协议在通信节点与控制中心之间通过多个GHZ对完成该密码的安全分配系统.与经典的利用EPR粒子纠缠态互换的量子密钥传输协议相比,在传输网络中,窃听者Eve如果参与了3方的通信,要获得有用信息,必然要不断的引入错误,于是该网络的节点和控制中心将会发现Eve,保证了改进的多用户网络安全性.     

基于广播机制的多方量子远程制备协议

量子态远程制备(RSP)是量子信息过程的一个重要分支。为了解决一个发送者向多个接收者同时制备相同量子态的问题,提出了基于广播机制的1对2三方量子态远程制备协议,并将其拓展到1对N多方量子态远程制备中。该协议使用GHZ态作为量子信道,通过构造两组特殊测量基,发送方进行两次多粒子投影测量,接收方根据测量结果进行幺正操作,最终实现1个发送者向多个接收者同时制备相同的粒子态。经分析,协议的这种广播制备模式可以适用于任意多个接收者的情形。     

Two-party quantum key agreement protocols under collective noise channel

Recently, quantum communication has become a very popular research field. The quantum key agreement (QKA) plays an important role in the field of quantum communication, based on its unconditional security in terms of theory. Among all kinds of QKA protocols, QKA protocols resisting collective noise are widely being studied. In this paper, we propose improved two-party QKA protocols resisting collective noise and present a feasible plan for information reconciliation. Our protocols’ qubit efficiency has achieved 26.67%, which is the best among all the two-party QKA protocols against collective noise, thus showing that our protocol can improve the transmission efficiency of quantum key agreement.     

Cryptanalysis of a multiparty quantum key agreement protocol based on commutative encryption

Recently, Sun et al. (Quantum Inf Process 15(5):2101–2111, 2016) proposed an efficient multiparty quantum key agreement protocol based on commutative encryption. The aim of this protocol is to negotiate a secret shared key among multiple parties with high qubit efficiency as well as security against inside and outside attackers. The shared key is the exclusive-OR of all participants’ secret keys. This is achieved by applying the rotation operation on encrypted photons. For retrieving the final secret key, only measurement on single states is needed. Sun et al. claimed that assuming no mutual trust between participants, the scheme is secure against participant’s attack. In this paper, we show that this is not true. In particular, we demonstrate how a malicious participant in Sun et al.’s protocol can introduce “a” final fake key to target parties of his choice. We further propose an improvement to guard against this attack.     

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。     

Semi-quantum information splitting using GHZ-type states

By using a generalized Greenberger–Horne–Zeilinger (GHZ) state in which is locally unitarily connected with standard GHZ state as a communication channel, semi-quantum key distribution is extended to study semi-quantum information splitting protocols for secret sharing of quantum information. In our scheme, quantum Alice splits arbitrary two, three and N-qubit states with two classical parties, Bob and Charlie, in a way that both parties are sufficient to reconstruct Alice’s original states only under the condition of which she/he obtains the help from another one, but one of them cannot. The presented protocols are helpful for both secure against certain eavesdropping attacks and economical in processing of quantum information.