A Hybrid Quantum Key Distribution Algorithm Integrating BB84 and Twin-Field QKD for Enhanced Security and Efficiency

Quantum Key Distribution (QKD) represents a revolutionary advancement in secure communication. It leverages principles of quantum mechanics to establish cryptographic keys between parties with theoretically unbreakable security. Among the various QKD protocols, BB84 (Bennett and Brassard, 1984) and Twin-Field QKD are prominent due to their foundational simplicity and advanced key generation efficiency, respectively. The BB84 protocol, as the first QKD protocol, uses quantum bits (qubits) in different bases to securely generate shared keys, while Twin-Field QKD enhances the key generation rate by exploiting quantum interference between distant entangled states, making it more suitable for long-distance communication. This work explores the integration of BB84 and Twin-Field QKD into a hybrid algorithm, aiming at combining the robustness of BB84 with the high key generation rate and entropy of Twin-Field QKD. The hybrid algorithm alternates between the two protocols, leveraging their individual strengths to optimize key generation performance. Simulation results indicate that the hybrid algorithm can effectively balance the robustness and simplicity of BB84 with the high efficiency and entropy of Twin-Field QKD. Specifically, the hybrid algorithm demonstrated an error rate of 8.9%, a key generation rate of 50%, and an entropy of 0.999 bits, which outperforms the compared algorithms.