Abstract Multi-party quantum key agreement protocols with traveling mode have attracted much attention due to their higher efficiency than protocols with distributing mode. Nevertheless, the structures with traveling mode are generally vulnerable to internal participants, i.e. collusive attack. In order to resist collusive attack, a multi-party quantum key agreement protocol based on nonorthogonal quantum pairs, bell states and their dualities, is proposed. In this paper, we propose the idea of mixed dense encoding on the Pauli operations and the Hadamard operation. The private key sequence of each participant is encoded into a sequence consisting of those single-particle unitary operations which will be performed on the nonorthogonal quantum pairs. In the end, all participants can extract the target common key by comparing the initial states with the final states of the nonorthogonal quantum pairs. The proposed structure has three considerable advantages. Firstly, thanks to the use of nonorthogonal quantum pairs and mixed encoding, the proposed protocol can resist collusive attack from internal participants efficiently. Secondly, the efficiency has been greatly improved. Furthermore, due to the fact that only quantum pairs and simple single-particle unitary transformations are used, the processions of the proposed protocols are simple and can be easily realized in current technology.
Abstract Multi-party quantum key agreement protocols with traveling mode have attracted much attention due to their higher efficiency than protocols with distributing mode. Nevertheless, the structures with traveling mode are generally vulnerable to internal participants, i.e. collusive attack. In order to resist collusive attack, a multi-party quantum key agreement protocol based on nonorthogonal quantum pairs, bell states and their dualities, is proposed. In this paper, we propose the idea of mixed dense encoding on the Pauli operations and the Hadamard operation. The private key sequence of each participant is encoded into a sequence consisting of those single-particle unitary operations which will be performed on the nonorthogonal quantum pairs. In the end, all participants can extract the target common key by comparing the initial states with the final states of the nonorthogonal quantum pairs. The proposed structure has three considerable advantages. Firstly, thanks to the use of nonorthogonal quantum pairs and mixed encoding, the proposed protocol can resist collusive attack from internal participants efficiently. Secondly, the efficiency has been greatly improved. Furthermore, due to the fact that only quantum pairs and simple single-particle unitary transformations are used, the processions of the proposed protocols are simple and can be easily realized in current technology.
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.
In this paper, we discuss in some detail how multiparty quantum key agreement protocols must be carefully designed and present a collusion attack to illustrate this point. Then, a secure circle-type multiparty quantum key agreement with Bell states is proposed. Bell states are used as the information carriers and transmitted among the participants, who embed their secrets into the traveling particles via certain encoding operations. In this way, all participants simultaneously obtain the same agreement key, i.e., the sum of their secret inputs, at the end of the protocol. Here, quantum state discrimination is utilized to design the encoding operations, which ensures that the proposed protocol is correct and secure against the presented collusion attack. Furthermore, it is shown that the proposed protocol satisfies three conditions of a secure quantum key agreement protocol in theory. In addition, these encoding operations consist of some common single-qubit gates, the Hadamard operator and four Pauli operators, which makes the proposed protocol feasible using current technology.
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.
Quantum key agreement (QKA) is to negotiate a final key among several participants fairly and securely. In this paper, we show that some existing travelling-mode multiparty QKA protocols are vulnerable to internal participant's attacks. Dishonest participants can exploit a favorable geographical location or collude with other participants to predetermine the final keys without being discovered. To resist such attacks, we propose a new travelling-mode multiparty QKA protocol based on non-orthogonal Bell states. Theoretical analysis shows that the proposed protocol is secure against both external and internal attacks, and can achieve higher efficiency compared with existing travelling-mode multiparty QKA protocols. Finally we design an optical platform for each participant, and show that our proposed protocol is feasible with current technologies.
Using quantum entanglement resource Bell states and Pauli operations, a universal N-party quantum key agreement protocol is proposed. Pauli operations are performed on part of the Bell state sequence to pass the private key, and the entanglement characteristics of different Bell states are used to realize N-party quantum key agreement. In the N-party quantum key agreement, each participant obtains the XOR secret keys of all participants based on the Bell measurement. Compared with other multi-party quantum key agreement protocols, the proposed N-party quantum key agreement has a feasible qubit efficiency of 1/2N.
In this study, we propose a single-state multi-party quantum key agreement (MQKA) protocol with single-particle measurement. Firstly, a single-state three-party quantum key agreement protocol with single-particle measurement is introduced, followed by a security analysis that validated its capability to resist potential internal and external attacks. Furthermore, we utilize multi-particle entangled states to present a multi-party version of the single-state multi-party quantum key agreement with single-particle measurement. In comparison to previous MQKA protocols, our approach presents the following advantages: it employs one kind of multi-particle entangled state as the quantum resource; eliminates the need for entanglement swapping techniques, unitary operations, or pre-shared keys between participants; uses only the X measurement basis and Z measurement basis; transmits fewer qubits; consumes fewer qubits; and has higher qubit efficiency.