Abstract
This paper presents the first software-based implementation of a hybrid quantum key distribution protocol designed for multi-user networks. The protocol combines two ways of communicating using quantum mechanics: a Twin-Field QKD approach and a measurement-device-independent phase that is based on the KMB09 model. The combination lets users make safe keys on a distributed network without having to trust a single, central node. Using the Qiskit framework, two independent Python modules were made to replicate each phase. The Twin-Field QKD phase represents coherent-state interference and phase noise. The KMB09-inspired phase, on the other hand, models BB84 state preparation, Bell-state measurements, and key sifting based on parity analysis. The codebase has sophisticated simulation logic, tools for visualizing networks, and tools for analyzing statistical performance. Tests with different amounts of loss, noise, and users show that the hybrid technique is both scalable and more secure against known quantum assaults. The results show that the protocol could be used in real-life quantum-secured communication networks in the future.