Practical Cross-Domain Quantum Fair Exchange for Next-Generation Networks via Functional Decoupling

Reconfigurable Quantum Key Distribution

Quantum key distribution (QKD) enables information-theoretically secure key exchange between two remote parties. However, practical implementations often are vulnerable to device imperfections, particularly in the state preparation. In this paper, we propose a reconfigurable QKD scheme based on arbitrary pure states. By reducing the number and accuracy of required quantum states, our approach simplifies implementation while enhancing robustness against practical imperfections. Within this framework, the communicating parties can dynamically reconfigure their system, adaptively selecting a subset of states based on the raw key, to implement various QKD protocols. We prove that the security of the proposed scheme can be reduced to that of standard QKD protocols with MUBs and full quantum state preparation, thereby inheriting the established security proofs of existing QKD protocols. To the best of our knowledge, the proposed scheme imposes the loosest and most straightforward requirements on state preparation, making it the most simplified QKD scheme to date. Notably, this reconfiguration provides greater resilience against state preparation flaws and can be seamlessly integrated into current systems without requiring any hardware modifications. Our work bridges the gap between theoretical security and practical implementation, paving the way for more reliable QKD deployments in real-world scenarios.

Trust-free quantum internet with distributed entanglement and reconfigurable shields

Dynamic Entanglement Distribution for Multi-User and Multi-Protocol Quantum Networking

A metropolitan-scale entanglement-based quantum communication network enabled by a quantum reconfigurable optical add-drop multiplexer (q-ROADM), which dynamically distributes polarisation-entangled photon pairs from a broadband source to six users over deployed campus and metropolitan fibre, is demonstrated.

Advancing the Quantum Internet and the Evolution of Network Technology

This study highlights the gap between theoretical developments and real-world deployment, and outlines future research directions required for building scalable and practical quantum network infrastructures.

GHZ-Equivalent State Distribution in Quantum Networks: Reducing Decoherence and Quantum Resource Consumption

This study proposes a novel scheme for distributing GHZ-equivalent states across repeater-based quantum networks, with particular focus on the analysis and mitigation of decoherence effects during transmission. The proposed scheme enables remote users to share graph states, which can be leveraged to implement various quantum communication protocols, such as quantum key distribution and quantum secret sharing. Compared with existing approaches, the proposed distributed scheme requires only O(N) qubits without introducing redundant entanglement structures. Together with the linear-scaling merging procedure in both controlled gate count and qubit usage, the proposed framework supports more efficient large-scale graph state distribution. To evaluate its feasibility and correctness, this study utilizes the quantum network simulation tool, NetSquid, to implement the proposed scheme. Simulation results demonstrate that the proposed approach is both effective and practical for executing quantum communication protocols within quantum networks.

A Scalable Multi-Protocol Platform for Quantum Key Distribution Simulation with Rigorous Statistical Evaluation

Quantum Key Distribution (QKD) offers information- theoretically secure key establishment grounded in the laws of quantum physics, yet its practical reach is limited by the prohibitive cost of photonic hardware and the fragmented nature of existing simulation tools. Most simulators support only a single protocol and report results from individual stochastic runs, making systematic protocol comparison and reproducible statistical inference difficult. This paper presents a unified QKD simulation platform that implements four foundational protocols BB84, B92, E91, and BBM92 within a single Python/Qiskit engine. A shared impairment model covers fiber attenuation, source and detector losses, po- larization drift, and configurable intercept-resend eavesdropping. The platform is accessible through two independent interfaces that share the same backend: a desktop application (Tkinter, Matplotlib) for local experimentation and a browser-based web client (React, Node.js/Express) for zero-install remote access. All reported results are drawn from repeated-run studies (20 independent runs, 10000 qubits each), with mean, standard deviation, and 95% confidence intervals stated throughout. At a 25 km fiber link, BB84 achieves the highest mean key-rate of 160,045 Hz, followed by BBM92 (80023 Hz), E91 (52815 Hz), and B92 (40011 Hz) ordering that tracks simulation-derived sifting efficiencies precisely. Under the E91 protocol, the CHSH S-statistic averages 2.12 at baseline and falls to 1.58 when an eavesdropper is activated, demonstrating Bell-inequality-based intrusion detection independent of QBER