Quantum Key Distribution (QKD) holds the promise of a secure exchange of cryptographic material between applications that have access to the same network of QKD nodes, interconnected through fiber optic or satellite links. Worldwide several such networks are being deployed at a metropolitan level, where edge computing is already offered by the telco operators to customers as a viable alternative to both cloud and on-premise hosting of computational resources. In this paper, we investigate the implications of enabling QKD for edge-native applications from a practical perspective of resource allocation in the QKD network and the edge infrastructure. Specifically, we consider the dichotomy between aggregating all the applications on the same source–destination path vs. adopting a more flexible micro-flow approach, inspired from Software Defined Networking (SDN) concepts. Our simulation results show that there is a fundamental trade-off between the efficient use of resources and the signaling overhead, which we managed to diminish with the use of suitable hybrid solutions.
Quantum Key Distribution (QKD) holds the promise of a secure exchange of cryptographic material between applications that have access to the same network of QKD nodes, interconnected through fiber optic or satellite links. Worldwide several such networks are being deployed at a metropolitan level, where edge computing is already offered by the telco operators to customers as a viable alternative to both cloud and on-premise hosting of computational resources. In this paper, we investigate the implications of enabling QKD for edge-native applications from a practical perspective of resource allocation in the QKD network and the edge infrastructure. Specifically, we consider the dichotomy between aggregating all the applications on the same source–destination path vs. adopting a more flexible micro-flow approach, inspired from Software Defined Networking (SDN) concepts. Our simulation results show that there is a fundamental trade-off between the efficient use of resources and the signaling overhead, which we managed to diminish with the use of suitable hybrid solutions.
Quantum Key Distribution (QKD) enables secure communications via the exchange of cryptographic keys exploiting the properties of quantum mechanics. Nowadays the related technology is mature enough for production systems, thus field deployments of QKD networks are expected to appear in the near future, starting from local/metropolitan settings, where edge computing is already a thriving reality. In this paper, we investigate the interplay of resource allocation in the QKD network vs. edge nodes, which creates unique research challenges. After modeling mathematically the problem, we propose practical online policies for admitting edge application requests, which also select the edge node for processing and the path in the QKD network. Our simulation results provide initial insights into this emerging topic and lead the way to upcoming studies on the subject.
The advent of cryptographically relevant quantum computers poses an existential threat to classical public-key infrastructure. Quantum Key Distribution (QKD) addresses this challenge by providing information-theoretic security for key establishment, independently of any computational hardness assumption. In this work, the deployment and experimental validation of a metropolitan-scale quantum-secure network between data centers in Milan is reported. The network operates over installed fiber infrastructure and implements a layered architecture integrating QKD hardware, standards-compliant Key Management (KM), and centralized Software-Defined Networking (SDN) orchestration. Dynamic path reconfiguration via active optical switching and trusted-node routing allow automated fail-over solutions. Application-layer validation across diverse protocols and workloads confirms the seamless interoperability of all system components. These results establish the technical and operational readiness of metropolitan QKD networks for production deployment, and offer a replicable blueprint for building quantum-secure communication infrastructure at metropolitan scale.
Quantum Key Distribution (QKD) is one of the major cryptographic solutions to tackle the security threats associated to future computational advances, in particular those coming from quantum computing. At the most simple level, QKD can be seen as a highly secure source of symmetric secret keys in two separated places. Nonetheless, the lack of standardization and the strong requirements from the physical layer makes this technology very difficult to integrate in existing infrastructure.However, the success of QKD networks radically depends on the degree in which they can be adopted in the existing infrastructure, and it is a must that it happens via standard protocols and interfaces. The flexibility of novel network paradigms, like Software-Defined Networking (SDN), allows for a faster adoption of new concepts, hardware and services in telecommunications networks. This paradigm can be used for quantum communications, allowing for a fast and scalable deployment of quantum technologies and services in the telecommunications network to a degree that was simply impossible in previous schemes, where the different network devices and their connections should be modified, one by one, to create a quantum communications channel.This tutorial provides an introduction to existing QKD technologies and networks, followed by a descriptive explanation on how SDN principles can be utilized to abstract and integrate QKD systems as part of the network management. This will help to reduce the time-to-market for quantum technologies, and also will make quantum cryptography available as a service to be capitalized by the network operators.
The rapid evolution of digital infrastructure has raised significant concerns about the security of data transmission, particularly with the advent of quantum computing. Traditional cryptographic algorithms are vulnerable to attacks, highlighting the need for quantum-resistant solutions. This paper presents the integration of Quantum Key Distribution (QKD) with Software-Defined Networking (SDN) and network slicing to build a secure, programmable, and flexible network architecture. QKD ensures unconditional security based on quantum mechanics by enabling key distribution with the ability to detect eavesdropping through quantum bit error rates (QBER). SDN provides centralized control and real-time traffic management, while network slicing allows isolation, reliability and customization of traffic flows for specific applications such as URLLC, eMBB, and mMTC. When abnormal QBER or decryption failures are detected, mitigation actions such as Quantum key refresh, traffic rerouting, or attacker isolation are triggered and Performance evaluation of the system is based on Latency and throughput Experimental validation using Mininet and Ryu demonstrates secure key distribution, attack detection, and slice-specific threat mitigation. This integrated approach enhances end-to-end security for next-generation networks, with strong applicability to5G/6G, IoT, and mission-critical services.
With the rapid advancement of quantum computing technology, IoT edge devices widely deployed in industrial settings are facing severe threats to their quantum-resistant security. This work focuses on the challenges of adapting Quantum Key Distribution (QKD) and Post-Quantum Cryptography (PQC) for resource-constrained environments. This work systematically identifies four critical obstacles: difficulties in physical integration due to device heterogeneity; constraints imposed by the limited computing power and storage resources of edge nodes on PQC algorithm execution; compatibility gaps between QKD/PQC and existing industrial protocols (such as Modbus and Profinet); and the engineering cost pressures associated with large-scale deployment. To address these issues, the paper proposes three synergistic lightweight countermeasures: (1) a tiered deployment architecture for quantum-safe security that accommodates device heterogeneity, enabling dynamic trade-offs between security strength and resource overhead; (2) middleware for quantum-classical hybrid network protocol coordination, ensuring seamless integration between QKD/PQC and industrial control protocols; and (3) a three-tier distributed key management mechanism (edge node, network proxy, and central system) that offloads computation- and storage-intensive tasks to high-resource nodes, thereby alleviating bottlenecks at the edge. Experimental validation within a smart manufacturing factory's sensor network demonstrates that the proposed scheme maintains post-quantum security capabilities (with QKD integration validated at the proof-of-concept level) while reducing per-node deployment costs by approximately 92.4% compared to pure QKD solutions and by about 32% compared to pure PQC solutions, all while facilitating seamless, non-disruptive upgrades. This study indicates that lightweight algorithm design, hardware-software co-optimization, and tiered architectural deployment constitute a viable pathway for advancing IoT edge security into the quantum-safe era.
Quantum key distribution (QKD) holds the potential of providing long-term integrity and confidentiality for data and communications. Currently, many fiber-based QKD systems have been commercialized and several QKD networks have been deployed. Given the high cost and complexity of QKD network deployment, QKD as a service (QaaS) becomes a promising pattern for future QKD networks. The QaaS concept is that multiple users can apply for QKD services to obtain their required secret-key rates (SKRs) from the same QKD network infrastructure instead of deploying their dedicated QKD networks. Accordingly, how to provide efficient and flexible QaaS for fulfilling the SKR requirements of multiple users over a QKD network infrastructure becomes a new challenge. This study introduces the software defined networking (SDN) technique to overcome this challenge, since SDN can add flexibility together with efficient QKD network management. A new framework of SDN for QaaS (SDQaaS) is proposed, where the QaaS functions are developed in the SDN controller. We present the protocol extension, intercommunication workflow, and routing and SKR assignment strategy for QaaS implementation in the SDQaaS framework. We also establish a SDQaaS experimental testbed and perform the numerical simulation to verify our presented approaches. Experimental results demonstrate that our presented approaches can achieve efficient and flexible QaaS over the QKD network. Moreover, simulation results indicate that the success probability of QKD service requests can be increased via lowering the flexibility of SKR requirements for QKD service creation, sacrificing more cost to produce higher SKR over the QKD network, or gradually reducing SKR requirements with the modification of QKD service.