Quantum key agreement is a promising key establishing protocol that can play a significant role in securing 5G/6G communication networks. Recently, Liu et al. (Quantum Information Processing 18(8):1-10, 2019) proposed a multi-party quantum key agreement protocol based on four-qubit cluster states was proposed. The aim of their protocol is to agree on a shared secret key among multiple remote participants. Liu et al. employed four-qubit cluster states to be the quantum resources and the X operation to securely share a secret key. In addition, Liu et al.'s protocol guarantees that each participant makes an equal contribution to the final key. The authors also claimed that the proposed protocol is secure against participant attack and dishonest participants cannot generate the final shared key alone. However, we show here that Liu et al. protocol is insecure against a collusive attack, where dishonest participants can retrieve the private inputs of a trustworthy participant without being caught. Additionally, the corresponding modifications are presented to address these security flaws in Liu et al.'s protocol.
Quantum key agreement is a promising key establishing protocol that can play a significant role in securing 5G/6G communication networks. Recently, Liu et al. (Quantum Information Processing 18(8):1-10, 2019) proposed a multi-party quantum key agreement protocol based on four-qubit cluster states was proposed. The aim of their protocol is to agree on a shared secret key among multiple remote participants. Liu et al. employed four-qubit cluster states to be the quantum resources and the X operation to securely share a secret key. In addition, Liu et al.'s protocol guarantees that each participant makes an equal contribution to the final key. The authors also claimed that the proposed protocol is secure against participant attack and dishonest participants cannot generate the final shared key alone. However, we show here that Liu et al. protocol is insecure against a collusive attack, where dishonest participants can retrieve the private inputs of a trustworthy participant without being caught. Additionally, the corresponding modifications are presented to address these security flaws in Liu et al.'s protocol.
With the emergence of the multi-party quantum key agreement, the participant attack has attracted great attention, since it is a destructive attack which is easier to obtain the effective information than the external attack. In this paper, a new multi-party quantum key agreement protocol with six-qubit cluster states which has the verification function is put forward. At first, a verifiable distributor is introduced to distribute the remaining information of six-qubit cluster states to any two adjacent participants after preserving a part. Next, once the participants verify the correctness of the received information with the properties of six-qubit cluster states under the X-basis, the cluster states are used as the quantum resource to perform the X operation in the participant operation phase. Finally, it can not only verify the correctness of the recovered shared key, but also guarantee its simultaneity through the trusted design combiner and homomorphic hash function. Furthermore, the security analysis shows that the new protocol can resist the external and internal attacks. And it's proved that our protocol is meaningful through the comparation analysis.
Fairness is an important standard needed to be considered in a secure quantum key agreement (QKA) protocol. However, it found that most of the quantum key agreement protocols in the travelling model are not fair, i.e., some of the dishonest participants can collaborate to predetermine the final key without being detected. Thus, how to construct a fair and secure key agreement protocol has obtained much attention. In this paper, a new fair multiparty QKA protocol that can resist the collusive attack is proposed. More specifically, we show that in a client-server scenario, it is possible for the clients to share a key and reveal nothing about what key has been agreed upon to the server. The server prepares quantum states for clients to encode messages to avoid the participants' collusive attack. This construction improves on previous work, which requires either preparing multiple quantum resources by clients or two-way quantum communication. It is proven that the protocol does not reveal to any eavesdropper, including the server, what key has been agreed upon, and the dishonest participants can be prevented from collaborating to predetermine the final key.
Abstract Quantum key agreement (QKA) is an important cryptographic primitive that plays a pivotal role in private communications. Authenticated QKA plays an important role in QKA. In this paper, we propose an authenticated multiparty QKA scheme based on 4-qubit cluster states entanglement swapping. The scheme is divided into two parts, the first part is the quantum identity authentication stage, and the second part is the QKA stage. In the quantum identity authentication stage, the participants determine that the participant communicating with them is the claimed person through mutual authentication, which can avoid the impersonation attack of the eavesdropper Eve. In the QKA phase, the participants adopt a bidirectional transmission structure with the participation of a semi-trusted third party, and based on the entanglement swapping property of the 4-qubit cluster state, the QKA is finally realized. Detailed security analysis shows that the protocol can resist a variety of internal and external attacks, such as participants attack, entangle-measure attack, and so on.
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.
Although there are many quantum key agreement protocols currently in existence, they cannot be merged in terms of resource utilisation, efficiency, security, and other aspects, and there are also significant differences in the nature of two and more parties. Therefore, it is necessary to design a quantum key agreement protocol that can balance efficiency and security and is suitable for multiple participants. In view of this, this paper proposes a multi-party quantum key agreement protocol based on a new coding mode of bell state: temporary session keys are negotiated between adjacent participants, and then shared keys for all participants are negotiated through the exchange, conversion, and computation of quantum resources. During the implementation of the protocol, not only can the identity of the participants be authenticated, but also the quantum resources used are single, and the quantum operations performed are simple. Moreover, efficiency is fixed and does not decrease due to the increase of participants or quantum resources. In addition, the protocol also allows participants to dynamically join and leave. In terms of security, the protocol can resist most common quantum attacks. Under the existing quantum technology, this protocol is completely feasible.
Although there are many quantum key agreement protocols currently in existence, they cannot be merged in terms of resource utilisation, efficiency, security, and other aspects, and there are also significant differences in the nature of two and more parties. Therefore, it is necessary to design a quantum key agreement protocol that can balance efficiency and security and is suitable for multiple participants. In view of this, this paper proposes a multi-party quantum key agreement protocol based on a new coding mode of bell state: temporary session keys are negotiated between adjacent participants, and then shared keys for all participants are negotiated through the exchange, conversion, and computation of quantum resources. During the implementation of the protocol, not only can the identity of the participants be authenticated, but also the quantum resources used are single, and the quantum operations performed are simple. Moreover, efficiency is fixed and does not decrease due to the increase of participants or quantum resources. In addition, the protocol also allows participants to dynamically join and leave. In terms of security, the protocol can resist most common quantum attacks. Under the existing quantum technology, this protocol is completely feasible.