An efficient circle-type multiparty quantum key agreement protocol utilizing two non-orthogonal bases single particles is proposed. In our protocol, each participant performs one of two simple unitary operations to encode and additional unitary operations to protect his privacy. Both outside attacks and participant attacks can be perfectly resisted. Moreover, our protocol has a high efficiency up to [Formula: see text], where [Formula: see text] is the number of the participants, and it can be easily implemented with current quantum technologies as it needs only single particle measurements.
An efficient circle-type multiparty quantum key agreement protocol utilizing two non-orthogonal bases single particles is proposed. In our protocol, each participant performs one of two simple unitary operations to encode and additional unitary operations to protect his privacy. Both outside attacks and participant attacks can be perfectly resisted. Moreover, our protocol has a high efficiency up to [Formula: see text], where [Formula: see text] is the number of the participants, and it can be easily implemented with current quantum technologies as it needs only single particle measurements.
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.
A new efficient two-party semi-quantum key agreement protocol is proposed with high-dimensional single-particle states. Different from the previous semi-quantum key agreement protocols based on the two-level quantum system, the propounded protocol makes use of the advantage of the high-dimensional quantum system, which possesses higher efficiency and better robustness against eavesdropping. Besides, the protocol allows the classical participant to encode the secret key with qudit shifting operations without involving any quantum measurement abilities. The designed semi-quantum key agreement protocol could resist both participant attacks and outsider attacks. Meanwhile, the conjoint analysis of security and efficiency provides an appropriate choice for reference on the dimension of single-particle states and the number of decoy states.
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.
This paper introduces the design process of a multiparty quantum key agreement protocol based on the Greenberger-Horne-Zeilinger state in detail. Building on the traditional circle-type quantum key agreement protocol, we introduce a star structure, which significantly improves the speed and efficiency of key agreement. To facilitate the reader’s understanding, we provide an example of a four participants quantum key agreement protocol. In the process of quantum state transmission, we perform operations using the Pauli matrix and the Hadamard matrix to ensure that the quantum state remains in one of the four basis states. This significantly enhances the security of the protocol. After rigorous security analysis, we find that the protocol can effectively resist intercept-resend attack, entangle-measure attack, collective attack, and dishonest participant attack. Under a collective attack, if the first particle is subjected to bit-flipping noise, then p<0.2430 only guarantees r>0.2 when a=1 . Additionally, we conduct a fairness analysis and evaluate the practical performance of the proposed protocol. In an ideal depolarization noise-free environment, the protocol can achieve a positive key rate only when the global detection efficiency exceeds 0.9636. Finally, we conduct a comprehensive comparative analysis of the protocols. The results show that our proposed protocol is superior to other existing schemes in terms of efficiency and running time.
As a burgeoning branch of quantum cryptography, quantum key agreement is a kind of key establishing processes where the security and fairness of the established common key should be guaranteed simultaneously. However, the difficulty on designing a qualified quantum key agreement protocol increases significantly with the increase of the number of the involved participants. Thus far, only few of the existing multiparty quantum key agreement (MQKA) protocols can really achieve security and fairness. Nevertheless, these qualified MQKA protocols are either too inefficient or too impractical. In this paper, an MQKA protocol is proposed with single photons in travelling mode. Since only one eavesdropping detection is needed in the proposed protocol, the qubit efficiency and measurement efficiency of it are higher than those of the existing ones in theory. Compared with the protocols which make use of the entangled states or multi-particle measurements, the proposed protocol is more feasible with the current technologies. Security and fairness analysis shows that the proposed protocol is not only immune to the attacks from external eavesdroppers, but also free from the attacks from internal betrayers.
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.