P. Toliver, Thomas E. Chapuran, Robert J. Runser, Nicholas A. Peters, Matthew S. Goodman, J. Jackel, Scott R. McNown, Richard Hughes, Charles G. Peterson, Kevin P. McCabe, J. E. Nordholt, K. Tyagi, Danna Rosenberg, N. Dallman
Quantum key distribution offers a unique opportunity in securing next-generation optical networks. Recent advances in the integration of QKD within conventional DWDM network environments will be presented along with guidelines for practical system engineering.
Quantum key distribution (QKD) constitutes a symmetric secret key negotiation protocol capable of maintaining information-theoretic security. Given the recent advances in QKD networks, they have evolved from academic research to some preliminary applications. A QKD network consists of two or more QKD nodes interconnected by optical fiber or free space links. The secret keys are negotiated between any pair of QKD nodes, and then they can be delivered to multiple users in various areas for ensuring long-term protection and forward secrecy. We commence by introducing the QKD basics, followed by reviewing the development of QKD networks and their implementation in practice. Subsequently, we describe the general QKD network architecture, its elements, as well as its interfaces and protocols. Next, we provide an in-depth overview of the associated physical layer and network layer solutions, followed by the standardization efforts as well as the application scenarios associated with QKD networks. Finally, we discuss the potential future research directions and provide design guidelines for QKD networks.
As the limitations of classical cryptographic systems become increasingly evident in the face of advancing quantum algorithms, Quantum Key Distribution (QKD) emerges as a vital paradigm for securing information in next-generation networks. This paper explores the theoretical foundations and protocol architectures underpinning QKD, including BB84, E91, and newer hybrid approaches designed for scalable integration into existing infrastructures. Performance metrics such as key generation rate, error thresholds, and resistance to various attack models are critically examined across both fiber-optic and free-space implementations. Furthermore, the study delves into real-world deployment challenges—ranging from synchronization errors and quantum channel noise to cost-efficiency and interoperability with classical systems. By offering a comparative analysis and proposing optimization strategies, this work aims to pave the way for robust quantum-secure communication protocols suited for large-scale, heterogeneous network environments.
Secure networks composed of optical networks and quantum key distribution (QKD) are considered in this paper. A network layer structure is defined to focus on issues important with respect to the QKD network layer that controls QKD links and supplies a secure key for message transmission. A multiple-user QKD network layer can be constructed with timing synchronization, secure key sharing between indirectly connected nodes with switched QKD systems and key relays, and key management to control the volume of key generation and supply in response to the demand from optical network nodes.
In last decade,many important results on quantum key distribution( QKD) have been achieved. QKD is physically secure in theory,however,it is not easy to realize an ideal QKD system in practice. On the one hand,side channel attack on QKD system will be a main threat which cannot be eliminated in the predictable future. On the other hand,QKD system does not have a full compatibility with conventional network because quantum signal is transmitted by fiber or free-space in point to point mode. Besides,the security of identification and data storage still cannot be solved by QKD. However,an integrated system on how to evaluate the security of QKD systemstill will play an important role in practical QKD system. Especially,new cryptography system is still the key factor toward the bright future of information security.
Increasing incidents of cyber attacks and evolution of quantum computing poses challenges to secure existing information and communication technologies infrastructure. In recent years, quantum key distribution (QKD) is being extensively researched, and is widely accepted as a promising technology to realize secure networks. Optical fiber networks carry a huge amount of information, and are widely deployed around the world in the backbone terrestrial, submarine, metro, and access networks. Thus, instead of using separate dark fibers for quantum communication, integration of QKD with the existing classical optical networks has been proposed as a cost-efficient solution, however, this integration introduces new research challenges. In this paper, we do a comprehensive survey of the state-of-the-art QKD secured optical networks, which is going to shape communication networks in the coming decades. We elucidate the methods and protocols used in QKD secured optical networks, and describe the process of key establishment. Various methods proposed in the literature to address the networking challenges in QKD secured optical networks, specifically, routing, wavelength and time-slot allocation (RWTA), resiliency, trusted repeater node (TRN) placement, QKD for multicast service, and quantum key recycling are described and compared in detail. This survey begins with the introduction to QKD and its advantages over conventional encryption methods. Thereafter, an overview of QKD is given including quantum bits, basic QKD system, QKD schemes and protocol families along with the detailed description of QKD process based on the Bennett and Brassard-84 (BB84) protocol as it is the most widely used QKD protocol in the literature. QKD system are also prone to some specific types of attacks, hence, we describe the types of quantum hacking attacks on the QKD system along with the methods used to prevent them. Subsequently, the process of point-to-point mechanism of QKD over an optical fiber link is described in detail using the BB84 protocol. Different architectures of QKD secured optical networks are described next. Finally, major findings from this comprehensive survey are summarized with highlighting open issues and challenges in QKD secured optical networks.
To face the quantum era and the prospect or threat of quantum computing, especially in a disaggregated network environment, the design and implementation of efficient quantum secure communication systems facilitating their integration in the optical network infrastructure is crucial. Quantum key distribution (QKD) is one of the most promising technologies to ensure long-term security. In particular, continuous-variable QKD results as an efficient solution more compatible and suitable to be integrated with conventional optical systems. In this work, quantum secure systems based on QKD for enabling a smooth and sustainable integration in optical networks are introduced, considering the related challenges, towards future secure 6G networks.