The paper addresses the development of quantum networks (QNs) with entanglementbased Quantum Key Distribution (QKD) protocols.The entanglement (the correlation among the quantum states of several particles) is an essential principle of quantum mechanics.This property has a major impact on the fields of application of QKD systems, the secured cryptographic key exchange and passive attack detection, while it can also be applied in quantum teleportation.Starting from the existing achievements in Europe (a QN for connecting several cities in Randstad, one of the main metropolitan regions in the Netherlands), a case study for a simulated entanglement-based QN is presented, including an ideal scenario (with noiseless QKD) and a nonideal one (with noisy QKD).The experimental settings are differentiated through the link and node fidelity.The simulation process produces general statistics, sender statistics, receiver statistics, the QBER (Quantum Bit Error Rate) and also the raw keys as generated by the entanglement-based protocol.No post-processing (non-quantic) phase is considered for the analyzed setting.Such simulations are useful for properly adjusting the design of a QN while taking into account its expected performance with respect to the non-ideal use-cases with errors that could be caused by an imperfect hardware or by potential eavesdropping actions.
The paper addresses the development of quantum networks (QNs) with entanglementbased Quantum Key Distribution (QKD) protocols.The entanglement (the correlation among the quantum states of several particles) is an essential principle of quantum mechanics.This property has a major impact on the fields of application of QKD systems, the secured cryptographic key exchange and passive attack detection, while it can also be applied in quantum teleportation.Starting from the existing achievements in Europe (a QN for connecting several cities in Randstad, one of the main metropolitan regions in the Netherlands), a case study for a simulated entanglement-based QN is presented, including an ideal scenario (with noiseless QKD) and a nonideal one (with noisy QKD).The experimental settings are differentiated through the link and node fidelity.The simulation process produces general statistics, sender statistics, receiver statistics, the QBER (Quantum Bit Error Rate) and also the raw keys as generated by the entanglement-based protocol.No post-processing (non-quantic) phase is considered for the analyzed setting.Such simulations are useful for properly adjusting the design of a QN while taking into account its expected performance with respect to the non-ideal use-cases with errors that could be caused by an imperfect hardware or by potential eavesdropping actions.
The paper addresses the Quantum Networks (QN) performance with Quantum Key Distribution (QKD) protocols.The focus is on networks with multi-hop paths (multiple QKD links with intermediate nodes).QKD emerged as a promising technology to ensure unconditioned communications security by exploiting the Quantum Computing (QC) and quantum principles.While the Point-to-Point (P2P) QKD links are well understood for several QKD protocols, the challenges concern the development of QN with multiple intermediate nodes and links.The deployment of quantum-secure communication systems over very large distances requires multi-hop QN.This paper presents a simulation-based case study for multi-hop QKD networks, focusing on the performance evaluation and the Cyber Security implications.The framework could be used to evaluate end-to-end key generation rates, latency, and resilience under various network topologies and link conditions.This methodology will allow to properly investigate how the network-level security policies can be integrated with QKD protocols to detect and mitigate both passive and active attacks.One could find out the trade-offs between hop count, security margins, and throughput, providing insights into the design of robust and scalable quantumsecure communication infrastructures.This study will support the research about the integration of the QKD with the classical network management, conventional security mechanisms and advanced Cyber defense strategies.
Abstract Since the 80 s when it was first proposed, Quantum Key Distribution (QKD) elicited great interest in the field of cryptography as a unique procedure for key generation that could in principle guarantee unconditionally secure communication “by the laws of Physics”. In the last fifteen years commercial solutions have started appearing on the market, showing that practical implementations of the protocol were not only possible but also competitive in terms of security and achievable secret-key rate. In this work we describe a simulation of the historical QKD protocol E91 on the IBM Quantum platform, making use of the qubit formalism to represent the quantum states received by two communicating nodes. Having implemented also the post-processing steps for the error correction and the privacy amplification, this model can represent a simple stand-alone tool to study the performance not only of one-to-one communication but of more complex systems that rely on QKD for security, one above all QKD networks.
Traditional cryptographic methods are becoming more and more vulnerable when facing the computing power delivered by the quantum algorithm in the era of digitalization heading towards quantum computing. The realization of a quantum computer is a growing menace that has promoted the development of Quantum Key Distribution (QKD), a completely secure key exchange protocol based on the principles of quantum mechanics. This work studies QKD protocol creation and use for secure data transfer in hybrid networks including both classical and quantum computing nodes over geographically separated environments. The paper provides a scalable scheme to integrate QKD with current classical communication networks, with the emphasis on interoperability, key synchronization, secure routing among the mixed nodes. At the core of the model are quantum channels for key exchange and classical channels for data, governed by a quantum-safe control protocol. The security of QKD—the feature of resistance against eavesdropping according to the no-cloning theorem and disturbance of measurement—is investigated taking into account actual implementation aspects, such as noise, restriction in a transmission distance, and quantum memory. To test the model, simulation, and prototype testing are performed over different networking topologies, considering various parameters such as QBER, key generation rate, latency and system robustness under different attacks such as man-in-the-middle as well as photon-number-splitting attacks. We also investigate the interworking between QKD and post-quantum cryptography (PQC) to reduce the risk for hybrid systems with enhanced security and to be backward compatible to classical systems. Findings show that, when well combined with classical and quantum computing nodes, QKD is able to bring the cybersecurity of today communication infrastructures to a greater extent. This research is a step towards building the quantum internet, providing a solid foundation for applications in cybersecurity and potentially well beyond — finance, defense, health care and more — where data privacy truly matters.
Quantum entanglement is a fundamental and intriguing phenomenon in quantum mechanics, wherein two or more particles become correlated in such a way that the state of one instantaneously influences the state of the other, regardless of the distance separating them. This research delves into the theoretical foundation of quantum entanglement, exploring its mathematical formulation, key experimental validations, and implications for emerging technologies. A primary focus is placed on its application in secure communication, particularly in Quantum Key Distribution (QKD), where entanglement enables fundamentally secure cryptographic protocols resistant to eavesdropping. We present an in-depth analysis of various QKD protocols, including BB84, E91, and decoy-state methods, assessing their security, efficiency, and practical feasibility. Recent experimental advancements in entanglement-based cryptography are examined, alongside real-world implementations and their technical challenges, such as photon loss, decoherence, and scalability in long-distance quantum communication networks. Additionally, we provide comparative insights into the efficiency of different QKD protocols using a bar chart, while figures and tables illustrate core quantum principles and experimental setups. By addressing both theoretical and practical aspects, this study contributes to a comprehensive understanding of quantum entanglement’s role in secure communication and highlights future directions for overcoming existing technological limitations.
Secure communication is crucial for intelligent infrastructure networks, especially in the field of vehicle-to-everything (V2X) communication. Real-time information ex change between vehicles is the cornerstone of traffic safety and intelligent decision making. However, existing V2X communication systems primarily rely on classical cryptographic security mechanisms, while the rapid development of quantum com puting fundamentally threatens their security guarantees. Quantum key distribu tion (QKD), based on the no-cloning principle of quantum mechanics, is considered a promising technology against quantum attacks. However, most existing studies focus on theoretical security analysis or static fiber optic transmission scenarios, lacking systematic evaluation of the complete QKD protocol workflow in highly dynamic V2X environments. To fill research gaps, this thesis constructs a vehicle-to-vehicle quantum key distribution (V2V-QKD) framework based on the Veins simulation platform, integrated with OMNeT++ and SUMO. The framework implements qubit preparation and trans mission, measurement, quantum bit error rate (QBER) estimation, error correction, and privacy amplification, aiming to evaluate the feasibility and robustness of QKD in dynamic V2V communication scenarios. This thesis designs two sets of experiments. The first set of experiments evaluates parameter robustness by varying the number of qubits transmitted in a single session and analyzing its impact on quantum error rate (QBER), final key length, and key generation rate. Experimental results show that when 𝑁raw = 800, the system achieves a favorable balance between QBER estimation stability and key generation reliability. The second set of experiments compares the performance of BB84 and SARG04 under gradually increasing eavesdropping and attack intensity. Results show that under no eavesdropping conditions, BB84 can stably generate longer keys, but its performance degrades significantly under attacks; while SARG04 generates shorter keys under ideal conditions, but remains relatively stable under increased attack interference. Comprehensive results demonstrate that, under optimized configuration, QKD can provide stable and secure key generation for V2V communication. Furthermore, an adaptive protocol selection strategy enhances system-level security resilience. This thesis verifies the feasibility of QKD in vehicular network environments and provides an experimental foundation and design reference for secure vehicular communication systems capable of withstanding quantum-era threats.
Abstract Quantum key distribution (QKD) is believed to represent a viable solution to achieve theoretically unconditionally secure key generation. However, the available optical systems for experimental QKD, based on photon transmission, are flawed by non-idealities that ultimately limit the achievable performance. Classical simulation of the optical hardware employed in these systems may take on a determining role in engineering future QKD networks. In this article, attempts for developing a QKD simulator based on low-computational-cost models of the employed hardware are presented. In particular, the simulation infrastructure targets polarization-based QKD setups with faint laser sources, whose behaviour can be described by semiclassical coherent states and Mean Photon Number (MPN) per beam. The effects of passive optical components on the photonic qubit evolution are described by Jones matrices, whose coefficients, for some commercial devices, are stored in anad-hoclibrary. Realistic eavesdropping attacks and non-idealities, such as optical losses, fibre attenuation, polarization misalignment and limited efficiency of single-photon detectors, are also taken into account. The infrastructure allows the user to describe the desired QKD configuration and it provides in output the MPN at the receiver and two fiducial performance parameters: Quantum Bit Error Rate (QBER) and secure key rate. The comparison of the simulation results with experimental data in the state-of-the-art literature highlights that this work is a step forward towards the definition of compact models for the hardware-dependent simulation of quantum-assisted communication networks.