A novel quantum dialogue protocol using triangle star cluster states for dynamic multiparty communication

Quantum secure direct communication (QSDC) is a key area of research in quantum cryptography, primarily due to its inherent ability to secure communication. However, existing QSDC protocols face notable limitations, particularly in terms of scalability and adaptability. These challenges are most pronounced in scenarios that involve multiparty participation and flexible modification of network topologies. Consequently, there is a pressing need to develop more dynamic and versatile quantum states that can address the complex demands of modern communication networks. In this paper, we introduce a novel cluster state, the triangle star cluster state, which is derived from the linear cluster state. We present a comprehensive method for preparing this state and conduct a detailed analysis of its properties. Due to its central symmetry and the ability to dynamically add or remove elements, we propose that the triangle star cluster state is highly suitable for the design of dynamic multiparty quantum communication protocols. As a specific application, we propose a dynamic point-to-multiparty quantum dialogue protocol. This protocol ensures secure communication and participant identity authentication by utilizing decoy photons and exploiting the unique properties of the triangle star cluster state under X-basis and Z-basis measurements. All participants share a secret ID via quantum key distribution (QKD) for identity authentication and measurement basis selection. Given the intrinsic security of QKD, the Pauli measurement rules, M and M+, established using the shared ID, ensure that any eavesdropping attempt disturbs the quantum states, thereby guaranteeing security. Moreover, the proposed protocol is capable of dynamically adjusting by adding or removing communication channels or participants as necessary. Unlike protocols based on simple Bell states, our approach utilizes the intrinsic graph-state properties to manage network topology through local operations, offering a unified framework for dynamic networks. Our analysis shows that the proposed protocol ensures a secure quantum dialogue with high communication efficiency. The design of this protocol underscores the potential of the triangle star cluster state in quantum communication networks based on star topologies.