Quantum Key Distribution (QKD) enables secure key exchange by leveraging quantum mechanics to provide theoretically unbreakable security. However, practical deployment of QKD networks is limited due to high costs, lack of interoperability of existing commercial products, and complex physical requirements. To address these challenges, digital twins of QKD networks provide an accessible and adaptable solution for testing and experimentation in emulated environments. This work presents the design of a digital twin model that emulates a QKD network under eavesdropping, allowing for realistic analysis of network behavior in the presence of security threats. As an initial stage, an emulation service of a QKD link with an eavesdropper has been implemented using the NetSquid simulator, offering a practical tool for testing QKD security. This model offers a versatile framework that can be adapted for use in different platforms and applications, providing not only a means to understand this threat and assess countermeasure effectiveness but also a method to analyze how attacks impact exchanged keys and the timing of key distribution.
Quantum Key Distribution (QKD) enables secure key exchange by leveraging quantum mechanics to provide theoretically unbreakable security. However, practical deployment of QKD networks is limited due to high costs, lack of interoperability of existing commercial products, and complex physical requirements. To address these challenges, digital twins of QKD networks provide an accessible and adaptable solution for testing and experimentation in emulated environments. This work presents the design of a digital twin model that emulates a QKD network under eavesdropping, allowing for realistic analysis of network behavior in the presence of security threats. As an initial stage, an emulation service of a QKD link with an eavesdropper has been implemented using the NetSquid simulator, offering a practical tool for testing QKD security. This model offers a versatile framework that can be adapted for use in different platforms and applications, providing not only a means to understand this threat and assess countermeasure effectiveness but also a method to analyze how attacks impact exchanged keys and the timing of key distribution.
Quantum technologies promise major advances in different areas. From computation to sensing or telecommunications, quantum implementations could bring significant improvements to these fields, arousing the interest of researchers, companies, and governments. In particular, the deployment of Quantum Key Distribution (QKD) networks, which enable the secure dissemination of cryptographic keys to remote application entities following Quantum Mechanics Principles, appears to be one of the most attractive and relevant use cases. Quantum devices and equipment are still in a development phase, making their availability low and their price high, hindering the deployment of physical QKD networks and, therefore, the research and experimentation activities related to this field. In this context, this paper focuses on providing research stakeholders with an open-access testbed where it is feasible to emulate the deployment of QKD networks, thus enabling the execution of experiments and trials, where even potential network attacks can be analyzed, without the quantum physical equipment requirement, nor compromising the integrity of an already built QKD network. The designed solution allows users to automatically deploy, configure, and run a digital twin environment of a QKD network, offering cost-effectiveness and great flexibility in the study of the integration of quantum communications in the current network infrastructures. This solution is aligned with the European Telecommunications Standard Institute (ETSI) standardized application interface for QKD, and is built upon open-source technologies. The feasibility of this solution has been validated throughout several functional trials carried out in the 5G Telefónica Open Network Innovation Centre (5TONIC), verifying the service performance in terms of speed and discarded qubits when generating the quantum keys.
Quantum technologies promise to boost ICT further by extending its limits, even by promising more effective and secure communications due to the benefits of quantum physics. This leads to Quantum Key Distribution (QKD), a cryptographic primitive for securely exchanging a secret key between distant endpoints, leveraging an insecure communication channel due to potential eavesdroppers. The literature on QKD started with the BB84 protocol proposed in 1984 and continued with other protocols, each with its pros and cons. Still, they have been chiefly designed for static scenarios and do not consider the needs of dynamic networks. This paper presents a QKD solution for dynamic networks combining adaptive key management techniques and fault-tolerant routing, ensuring high security and efficiency even in variable network topologies. Using MDI-QKD (Measurement Device Independent QKD) and simulations with NetSquid, we provide a preliminary assessment of this solution's robustness against dynamic attacks and the improvement in quantum resource management. The work also compares the protocol's effectiveness with existing solutions, highlighting the advantages and potential practical applications.
This paper investigates the increasing concerns related to the vulnerability of contemporary security solutions in the face of quantum-based attacks, which pose significant challenges to existing cryptographic methods. Most current Quantum Key Distribution (QKD) protocols are designed with a focus on point-to-point communication, limiting their application in broader network environments where multiple users need to exchange information securely. To address this limitation, a thorough analysis of twin-field-based algorithms is conducted, emphasizing their distinct characteristics and evaluating their performance in practical scenarios in Sections II, III, and IV. By synthesizing insights from these analyses, integrating cutting-edge advancements in Quantum Communication technologies, and drawing on proven methodologies from established point-to-point protocols, this study introduces a novel concept for a Hybrid Twin-Field QKD protocol in Section IV. This network-oriented approach is designed to facilitate secure communication in networks involving multiple users, offering a practical and scalable solution. The proposed protocol aims to reduce resource consumption while maintaining high-security standards, thereby making it a viable option for real-world quantum communication networks. This work contributes to the development of more resilient and efficient quantum networks capable of withstanding future quantum-based threats.
Quantum Key Distribution (QKD) offers information-theoretic security by leveraging quantum mechanics, yet the cost and complexity of dedicated hardware and fiber infrastructure have so far limited large-scale deployment and experimentation. In this paper, we introduce Quditto, an automated open-access emulation platform that combines high-fidelity quantum-channel modeling with a standardized key-delivery API, enabling users to interact with the emulated network exactly as they would with real QKD hardware. Quditto modular design supports pluggable protocol implementations, complex key management schemes and detailed channel models, including variable attenuation and decoherence. We validate Quditto by deploying networks of various sizes and demonstrate its flexibility through two proof-of-concept scenarios featuring eavesdropper attacks and heterogeneous channel conditions.
As concerns about the robustness of current security solutions against quantum-based attacks continue to escalate, the limitations of existing Quantum Key Distribution (QKD) protocols, which are predominantly designed for point-to-point communication scenarios, become increasingly apparent. This paper addresses these limitations by conducting a comprehensive analysis of contemporary twin-field-based algorithms, examining their individual characteristics and overall performance metrics. By synthesizing insights from Twin-Field QKD protocols, cutting-edge advancements in Quantum Communication technologies, and well-established point-to-point solutions, a novel network-oriented concept for a Hybrid Twin-Field QKD protocol is proposed. This innovative approach aims to facilitate secure quantum communication among multiple users within a network, offering a practical and resource-efficient alternative to traditional point-to-point methods. The proposed Hybrid Twin-Field QKD protocol seeks to address the need for scalable and robust security solutions in the face of evolving quantum threats, thereby enhancing the effectiveness, applicability, and efficiency of quantum key distribution systems in multi-user network environments.
The increasing number of cyber threats and the approaching development of quantum computing demand a critical review of existing cryptographic approaches. The goal of this work is to evaluate the security and practicality of utilizing Quantum Key Distribution for secure communications. QKD utilizes the laws of quantum mechanics to provide a secure and unbreakable method for exchanging information. Protocols like BB84 are resistant to threatening attacks from both classical and quantum adversaries. The methodology utilizes simulated models and quantum communication toolkits to study critical characteristics such as key generation speed, QBER, latency and scalability. Performance of QKD is compared to that of classical schemes such as RSA-2048, ECC-256 and AES-256. Results reveal that although QKD provides unparalleled theoretical security, its deployment has notable obstacles such as intricate infrastructure, restrictions on distance and elevated latency. Our study reveals that optimizing the interplay between security and practicality in QKD deployment can yield a highly effective safeguard for next-generation communication networks.