In this paper, we introduce a novel modification to the BB84 Quantum Key Distribution (QKD) protocol, aimed at enhancing its efficiency through the use of quantum memory and delayed measurement. In the standard BB84 protocol, the receiver immediately measures the qubits sent by the sender using randomly chosen bases. Due to mismatches between the sender and receiver's bases, a significant portion of the qubits are discarded, reducing the overall key generation rate. Our proposed protocol allows the receiver to store the received qubits in quantum memory and defer measurement until after the sender reveals her basis choices, effectively eliminating the need to discard mismatched qubits. This modification improves the key generation efficiency while maintaining the core security features of the standard BB84 protocol. By avoiding the unnecessary loss of qubits, our protocol achieves a higher secret key rate without introducing additional vulnerabilities. We present a detailed step-by-step explanation of the delayed measurement process. Although this approach does not alter the security guarantees of BB84, it represents a significant improvement in efficiency, making the protocol more viable for large-scale quantum communication networks.

翻译：本文提出一种对BB84量子密钥分发协议的新颖改进方案，旨在通过量子存储器与延迟测量提升协议效率。在标准BB84协议中，接收方需立即使用随机选择的基矢对发送方传输的量子比特进行测量。由于收发双方基矢选择不匹配，相当比例的量子比特被丢弃，导致整体密钥生成率降低。我们提出的协议允许接收方将接收到的量子比特存储于量子存储器中，待发送方公布其基矢选择后再进行测量，从而有效避免了不匹配量子比特的丢弃。该改进方案在保持标准BB84协议核心安全特性的同时，显著提升了密钥生成效率。通过避免量子比特的不必要损耗，本协议在未引入额外安全漏洞的前提下实现了更高的密钥生成率。文中对延迟测量过程进行了逐步详尽的阐释。虽然该方法未改变BB84协议的安全保障机制，但其效率的显著提升使得该协议更适用于大规模量子通信网络。