In the Internet Age, optical networks are vulnerable to numerous cyberattacks, and conventional key distribution methods suffer from the increased computational power. QKD can distribute information-theoretically secure secret keys between two parties based on the principles of quantum mechanics. Integrating QKD into optical networks can leverage existing fiber infrastructures with wavelength division multiplexing for the practical deployment of secret keys, and accordingly employ the secret keys for optical-layer security enhancement. Then, how to efficiently deploy and employ secret keys over QKD-integrated optical networks are emerging as two challenges. This article proposes a framework of key as a service (KaaS, i.e., providing secret keys as a service in a timely and accurate manner to satisfy the security requirements) to jointly overcome these two challenges. To enable the typical functions (i.e., secret-key deployment and employment) in KaaS, two secret-key virtualization steps, that is, key pool (KP) assembly and virtual key pool (VKP) assembly, are introduced. Also, we illustrate a new QKD-integrated optical network architecture from a holistic view, where the control layer is implemented by software defined networking for efficient network management. A time-shared KP assembly strategy and an on-demand VKP assembly strategy are presented for KaaS implementation. The success probabilities of KP assembly and VKP assembly are defined to evaluate the benefits of KaaS for efficiently deploying and employing secret keys as well as for security enhancement over QKD-integrated optical networks.
In the Internet Age, optical networks are vulnerable to numerous cyberattacks, and conventional key distribution methods suffer from the increased computational power. QKD can distribute information-theoretically secure secret keys between two parties based on the principles of quantum mechanics. Integrating QKD into optical networks can leverage existing fiber infrastructures with wavelength division multiplexing for the practical deployment of secret keys, and accordingly employ the secret keys for optical-layer security enhancement. Then, how to efficiently deploy and employ secret keys over QKD-integrated optical networks are emerging as two challenges. This article proposes a framework of key as a service (KaaS, i.e., providing secret keys as a service in a timely and accurate manner to satisfy the security requirements) to jointly overcome these two challenges. To enable the typical functions (i.e., secret-key deployment and employment) in KaaS, two secret-key virtualization steps, that is, key pool (KP) assembly and virtual key pool (VKP) assembly, are introduced. Also, we illustrate a new QKD-integrated optical network architecture from a holistic view, where the control layer is implemented by software defined networking for efficient network management. A time-shared KP assembly strategy and an on-demand VKP assembly strategy are presented for KaaS implementation. The success probabilities of KP assembly and VKP assembly are defined to evaluate the benefits of KaaS for efficiently deploying and employing secret keys as well as for security enhancement over QKD-integrated optical networks.
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.
Software-defined optical networking (SDON) will become the next generation optical network architecture. However, the optical layer and control layer of SDON are vulnerable to cyberattacks. While, data encryption is an effective method to minimize the negative effects of cyberattacks, secure key interchange is its major challenge which can be addressed by the quantum key distribution (QKD) technique. Hence, in this paper we discuss the integration of QKD with WDM optical networks to secure the SDON architecture by introducing a novel key on demand (KoD) scheme which is enabled by a novel routing, wavelength and key assignment (RWKA) algorithm. The QKD over SDON with KoD model follows two steps to provide security: i) quantum key pools (QKPs) construction for securing the control channels (CChs) and data channels (DChs); ii) the KoD scheme uses RWKA algorithm to allocate and update secret keys for different security requirements. To test our model, we define a security probability index which measures the security gain in CChs and DChs. Simulation results indicate that the security performance of CChs and DChs can be enhanced by provisioning sufficient secret keys in QKPs and performing key-updating considering potential cyberattacks. Also, KoD is beneficial to achieve a positive balance between security requirements and key resource usage.
Data transmission with optical fiber is vulnerable to eavesdropping. Moreover, conventional key distribution technology suffers from increasing computational power and upgraded attack algorithms. To address these issues, quantum key distribution (QKD), a quantum technology that secures secret information (such as a cryptographic key) exchange between two parties, can be used to guarantee secure data transmission. Integrating QKD into existing wavelength division multiplexing optical networks has been verified through a series of experiments, which contribute to ensuring network security and saving fiber resources. This paper addresses the resource assignment problem in QKD-enabled optical networks. First, a QKD-enabled optical network architecture is introduced. A small fraction of wavelength channels are segmented into multiple time slots with optical time division multiplexing technology to construct quantum key channels (QKChs) and measuring-basis channels, and then the remaining wavelengths can construct traditional data channels. Second, a static routing, wavelength, and time-slot assignment (RWTA) strategy is proposed and verified by the integer linear programming formulation and a heuristic algorithm. In the RWTA, QKChs are assigned for service requests according to the security levels specified by relevant key-updating periods. Thus, the secret keys for data encryption can update periodically to enhance security. Simulation results indicate that there is a trade-off between security (i.e., security levels and security-level types) and resource utilization.
It is well known that optical access networks are able to provide high data rates over long distances and to a reasonable number of users. Security and privacy are always a challenge for public accessible network infrastructures. Especially in time-division multiplexing passive optical networks (TDM-PONs), in which the downstream signal is broadcasted to all users connected via the same wavelength channel in a shared fiber link, privacy can be a critical concern. Although encryption at the application layer can provide a high level of security, this can be achieved only if the encryption key distribution is perfectly save. On the other hand, encryption on the physical layer such as quantum cryptography or, more precisely, quantum key distribution (QKD) is a very promising approach to achieve secure communication. However, there remain several issues that have to be solved before the quantum cryptography reaches the maturity level needed for a cost effective implementation in practical networks. In this paper, we address quantum key distribution (QKD) over passive optical access networks, which is an enabling technology required to cost efficiently deploy practical quantum encrypted data communication in the access area. We study different methods to integrate QKD systems in conventional optical access networks and quantitatively evaluate their suitability for a potential implementation.
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.
There is a great attention to quantum technologies in the ICT environment. In particular, when dealing with security matters, the most prominent quantum technology is Quantum Key Distribution (QKD). QKD allows the sharing of symmetric keys with information theoretic security (ITS, i.e. independently of the computational power of the attacker) between two remote network nodes. QKD is the only known method to share a key able to reach ITS. During the last two decades, there has been a tremendous technological progress in QKD research, that has led to the availability of QKD network demonstrators.Software Defined Networks (SDN) enables the automation of service provisioning within network operator infrastructures. With the advent of web-scale services and dynamic network requirements, operators can not anymore deploy their services based on manual intervention or using proprietary vendor solutions. Programmability is key in the next-generation network infrastructure and any new technology must be integrated with this paradigm. Let us highlight that this requirement is even more important with virtual environments, where a Virtual Network Function (VNF) can be deployed in any point-of-presence of the operator. The new 5G deployments will enable operators to have edge computing services supporting different capabilities, thus increasing even more the complexity to deliver services without any automation.In spite of the high potential of QKD, this technology has not yet found its path to wide adoption, commercialization and deployment. QKD is a physical technology that requires the existence of a quantum channel, a physical connection able to transmit quantum bits without perturbation, making hard its integration in networks. The aim of this document is to present how QKD can be deployed in next generation infrastructures, based on realistic scenarios. To do so, this paper describes the technological components of the solutions, as well as the use cases that motivate such effort. These use cases are described from a telecommunication provider's point of view, as they are the actors in charge of deploying QKD systems in their networks.