As quantum computers advance, they pose a growing threat to traditional encryption methods that protect sensitive information. Quantum Key Distribution (QKD) offers a secure alternative by using quantum mechanics to create shared secret keys whose interception can be detected. Integrating this technology into existing networks is essential to enable quantum-safe communications without requiring new infrastructure. This dissertation explores how Continuous-Variable Quantum Key Distribution (CV-QKD) systems can be integrated into current network infrastructures. It discusses relevant models, architectures, and standards that support this integration, focusing on how the SoftwareDefined Networking (SDN) model can standardize and simplify communication between QKD systems and traditional networks.
As quantum computers advance, they pose a growing threat to traditional encryption methods that protect sensitive information. Quantum Key Distribution (QKD) offers a secure alternative by using quantum mechanics to create shared secret keys whose interception can be detected. Integrating this technology into existing networks is essential to enable quantum-safe communications without requiring new infrastructure. This dissertation explores how Continuous-Variable Quantum Key Distribution (CV-QKD) systems can be integrated into current network infrastructures. It discusses relevant models, architectures, and standards that support this integration, focusing on how the SoftwareDefined Networking (SDN) model can standardize and simplify communication between QKD systems and traditional networks.
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.
Several technological challenges are currently posed by future 6G networks to support ultra-high capacity and dynamic connectivity, while ensuring environmental and societal sustainability, scalability, and reliability. Among them, security is a crucial aspect, particularly considering open and disaggregated networks. Continuous variable quantum key distribution (CV -QKD) is proposed as an appealing solution to ensure long-term security, while facilitating the coexistence with conventional optical communications for a sustainable integration of QKD technology in future 6G networks. In this work, the adoption of CV -QKD in future optical networks is discussed, focusing on the network resources and infrastructure sharing, exploring advanced features, flexibility and programmability, further enabled by software defined networking (SDN).
Software-Defined Networking (SDN) is an emerging networking paradigm that decouples the control and data plane in order to enable programmable and flexible networks, optimizing its applications and advancing computer systems. It does so through its architecture, a key part of which is a centralized network management through open interfaces that revolutionizes the way in which networks are designed and makes them more agile and versatile to the evolving needs of modern and future applications services. This also means, however, that there is now a centralized point of attack that is a major vulnerability, threatening the security of the entire network. With such an advanced network paradigm, it requires a security system that will mitigate these risks and warrant long-term security. In attempts to allow secure communications within the network, this research proposes the implementation of Quantum Key Distribution (QKD), leveraging quantum mechanics to secure the network against any computational advancements in the future. QKD is a recent cryptographic system that includes a traditional-computational channel and a physical-quantum channel to generate and distribute keys between parties. It uses the principles of quantum mechanics including entanglement and superposition to ensure that the physical layer cannot be compromised computationally. QKD provides confidentiality and privacy of information and communication. Moreover, it is resistant to technological advancements. The implications of QKD significantly enhance SDN security through its protection against attacks, efficient key distribution, reliable network orchestration, and data integrity, creating an architecture that establishes stable communication channels that are resistant to cyber threats.
To face the challenges of open and disaggregated 6G networks and the prospect/threat of quantum computing, we propose to adopt continuous-variable QKD (CV-QKD), as a promising technology compatible and suitable to be integrated with conventional optical systems, in combination with software defined networking (SDN). In this work, we present our most recent advances on SDN-enabled flexible CV-QKD for future secure communications. We describe the proposed network architecture, identifying the relevant parameters and interfaces. We consider and analyze a Gaussian-modulated coherent state CV-QKD system, reporting recent experimental results at the varying of the QKD system wavelength, as relevant adaptable parameter, that can be configured by the SDN controller, for distributing highly secure keys in metropolitan networks. The capabilities and potentialities of our proposed approach for future secure communications in open and disaggregated 6G networks are also discussed.
The growing dependence on digital communications underscores the need to protect data as it travels through the network. Internet Protocol Security (IPsec) plays a central role, providing a robust framework to ensure the confidentiality, integrity, and authenticity of transmitted data. However, advances in Quantum Computing pose a significant threat to current public-key cryptographic schemes by enabling efficient solutions to factoring and discrete logarithm problems. A promising solution also arises from the quantum domain. Quantum Key Distribution (QKD) provides a security layer immune to any computational attacks, whether quantum or classical. While the rapid adoption of quantum-safe technologies is highly desirable, it is equally important to ensure the resilience of existing trusted infrastructures, as the introduction of novel technologies may also entail unforeseen challenges. Enabling an evolutionary path that brings our current security infrastructure to a quantum-safe one, protected against both present and future threats, is thus very important. This work proposes a solution that integrates emerging quantum technologies into the existing security and communications infrastructure to ensure long-term protection. We focus on IPsec —one of the most widely deployed security protocols— and combine it with Software-Defined Networking (SDN) and QKD to construct a novel network security infrastructure that is resilient against both classical and quantum computational threats. Building upon recent standardization initiatives and operational tools for QKD integration, we demonstrate advanced capabilities -including rekeying and secure key transport- on a field deployed QKD network operating within a shared quantum-classical production infrastructure.