Conventional Quantum Key Distribution (QKD) requires the transmission of multiple qubits equivalent to the length of the key. As quantum networks are still in their infancy thus, they are expected to have a limited capacity, necessitating too many qubit transmissions for QKD might limit the effective use of limited network bandwidth of quantum networks. To address this challenge and enhance the practicality of QKD, we propose a Multi-Qubit Greenberger Horne Zeilinger (GHZ) State-based QKD scheme that requires a small number of qubit transmissions. The proposed method transmits one qubit between endpoints and reuses it for the transmission of multiple classical bits with the help of Quantum nondemolition (QND) measurements. We show that one can transfer L-1 classical bits by generating an L-qubit GHZ state and transferring one to the remote party. We further show that the proposed QKD algorithm can be extended to enable multi-party QKD. It can also support QKD between parties with minimal quantum resources. As a result, the proposed scheme offers a quantum network-efficient alternative QKD.

翻译：传统量子密钥分发（QKD）需要传输与密钥长度等量的多个量子比特。由于量子网络仍处于发展初期，其容量预计有限，因此QKD中过多的量子比特传输可能会限制量子网络有限带宽的有效利用。为解决这一挑战并提升QKD的实用性，我们提出了一种基于多量子比特格林伯格-霍恩-泽林（GHZ）态的QKD方案，该方案仅需少量量子比特传输。所提方法在端点间传输一个量子比特，并借助量子非破坏性（QND）测量将其重复用于多个经典比特的传输。我们证明，通过生成L量子比特GHZ态并将其中一个量子比特传输至远程方，可传输L-1个经典比特。进一步研究表明，所提QKD算法可扩展至支持多方QKD，并能在量子资源极少的条件下实现参与方间的QKD。因此，该方案为量子网络提供了一种高效的QKD替代方案。