The technological maturity of Quantum Key Distribution (QKD) products have generated high demand for secure key distribution in transmitting sensitive data. To provide this service, long-haul network operators are exploring strategies for network-wide deployment of QKD devices while utilizing existing infrastructure. One approach is to place trusted nodes at existing in-line amplifier huts in the network. In this study, we present a near-optimal fiber span aggregation algorithm, which effectively minimizes the number of trusted nodes between Points-of-Presences (PoPs) in the network. In this study, we evaluate six different topological QKD network deployments and eight different technological QKD network deployments in terms of the total secure key rate, as well as the number of QKD fiber pairs deployed. Our results indicate that the span aggregation algorithm increases the distance between each trusted node by up to 20%, thereby reducing the overall number of trusted nodes. Capacity planning for various topologies and technology deployments on simulated Secure Application Entity (SAE) requests is undertaken. Our proposed capacity planning shows that a baseline deployment with span aggregation using a QKD device with a cut-off distance of 140 km can save up to 3 times the number of QKD deployed fibers as compared to a minimum spanning tree-based low-cost deployment.
The technological maturity of Quantum Key Distribution (QKD) products have generated high demand for secure key distribution in transmitting sensitive data. To provide this service, long-haul network operators are exploring strategies for network-wide deployment of QKD devices while utilizing existing infrastructure. One approach is to place trusted nodes at existing in-line amplifier huts in the network. In this study, we present a near-optimal fiber span aggregation algorithm, which effectively minimizes the number of trusted nodes between Points-of-Presences (PoPs) in the network. In this study, we evaluate six different topological QKD network deployments and eight different technological QKD network deployments in terms of the total secure key rate, as well as the number of QKD fiber pairs deployed. Our results indicate that the span aggregation algorithm increases the distance between each trusted node by up to 20%, thereby reducing the overall number of trusted nodes. Capacity planning for various topologies and technology deployments on simulated Secure Application Entity (SAE) requests is undertaken. Our proposed capacity planning shows that a baseline deployment with span aggregation using a QKD device with a cut-off distance of 140 km can save up to 3 times the number of QKD deployed fibers as compared to a minimum spanning tree-based low-cost deployment.
Quantum key distribution (QKD) has become a promising option for transmitting sensitive data due to the increased maturity of QKD devices and the threat scalable quantum computers imposes on asymmetric public-key cryptosystems. By utilizing existing infrastructure, e.g., amplifier huts and dark fibers, the cost and complexity of deploying QKD networks (QKDNs) can be reduced. In this study, we develop a topology optimization algorithm that minimizes the cost of the QKDN deployment and maximizes the key capacity between any pair of nodes. We present three deployment upgrade strategies for facilitating the encryption of increasing throughput of QKD-secured optical transport networks and enabling a pay-as-you-grow approach. Comparing different strategies in a capacity-planning study allows operators to assess the scalability of deployments and upgrades. Depending on the availability requirements, our results compare the cost of protection measures. We confirm that adding trusted nodes is the most cost-efficient upgrading strategy based on our analysis.
Quantum communication infrastructure (QCI) is gradually becoming a favorable choice for transmitting secure data across the globe. Network operators often prefer to utilize the existing network infrastructure to reduce network setup costs to build a QCI. This implies transforming traditional network nodes to quantum nodes (QNs) by equipping them with quantum processors. Trusted repeater nodes (TRNs) are used to connect distant QNs. However, the network infrastructure cost increases with the number of TRNs due to the usage of dark fibers. Therefore, it is challenging for the network planning to build a QCI that connects all QNs with a minimum number of TRNs to reduce the infrastructure cost. In this work, we construct a minimum cost spanning tree for the QCI to connect all QNs with a minimum number of links and TRNs. The proposed approach considers node distance and attenuation cost of the physical connections. Compared to the traditional spanning tree approach, our proposed approach reduces the cost of QCI deployment by 10.90%.
A quantum key distribution (QKD) network is an infrastructure that allows the realization of the key distribution cryptographic primitive over long distances and at high rates with information-theoretic security.In this work, we consider QKD networks based on trusted repeaters from a topology viewpoint, and present a set of analytical models that can be used to optimize the spatial distribution of QKD devices and nodes in specific network configurations in order to guarantee a certain level of service to network users, at a minimum cost.We give details on new methods and original results regarding such cost minimization arguments applied to QKD networks.These results are likely to become of high importance when the deployment of QKD networks will be addressed by future quantum telecommunication operators.They will therefore have a strong impact on the design and requirements of the next generation of QKD devices.
Quantum key distribution (QKD) revolutionizes secure communication, offering unbreakable cryptography against quantum computers’ rising computational power. This paper explores the placement of trusted nodes to enhance the efficiency of quantum communication networks. Two practical scenarios are investigated: the multi-band (MB) setting, utilizing different wavelength bands for QKD and classical systems, and the multifiber (MF) solution, employing separate fibers for QKD and classical communication. The study optimizes secret key rate (SKR) per quantum transmitter and receiver (Q-TRx) in metro quantum-optical networks. A heuristic algorithm, considering noise sources and fiber attenuation, is proposed for routing, modulation, spectrum, and time assignment. The simulations conducted on various network topologies reveal optimal QKD trusted node distances (QTND) and wavelengths place. The simulation results indicate that the optimal QTND value for the MB-scenario and MF-scenario is 20 and 25 km, respectively. Compared to scenarios without QKD trusted node placement along the 40 km link, both the MB-scenario and MF-scenario exhibit 40% and 15% improvements, respectively, in SKR/QTRx relative to their optimal QTND values.
Quantum Key Distribution (QKD) has demonstrated unique and significant advantages in secure communication. In particular, Measurement-Device-Independent QKD (MDI-QKD), which is independent of measurement devices, increases data transmission distances and addresses the issue of low security in trusted relays. Therefore, in this work, we investigate QKD networks based on trusted and untrusted relays over optical backbone networks, providing a cost-optimal solution for the deployment and implementation of QKD networks. Specifically, this paper describes the QKD network and defines a new cost model, which not only fully considers the diverse impact factors of deployment costs but also meets the requirements for sharing network elements in response to different QKD chain requests. Based on cost model, this paper further proposes a cost-optimal heuristic algorithm for hybrid QKD network deployment, which can provide an economical and secure deployment solution for QKD networks. Extensive simulation experiments are conducted and the experimental results show that the proposed method outperforms current mainstream QKD network deployment algorithms in both deployment cost and security. Moreover, as the network scale increases, the advantages of our algorithm become more pronounced. Compared to mainstream algorithms, our method achieve an improvement of 17.7% -64.3% in cost savings and 1.19 to 3.24 times in security levels.
Quantum key distribution (QKD) has demonstrated a great potential to provide future-proofed security, especially for 5G and beyond communications. As the critical infrastructure for 5G and beyond communications, optical networks can offer a cost-effective solution to QKD deployment utilizing the existing fiber resources. In particular, measurement-device-independent QKD shows its ability to extend the secure distance with the aid of an untrusted relay. Compared to the trusted relay, the untrusted relay has obviously better security, since it does not rely on any assumption on measurement and even allows to be accessed by an eavesdropper. However, it cannot extend QKD to an arbitrary distance like the trusted relay, such that it is expected to be combined with the trusted relay for large-scale QKD deployment. In this work, we study the hybrid trusted/untrusted relay based QKD deployment over optical backbone networks and focus on cost optimization during the deployment phase. A new network architecture of hybrid trusted/untrusted relay based QKD over optical backbone networks is described, where the node structures of the trusted relay and untrusted relay are elaborated. The corresponding network, cost, and security models are formulated. To optimize the deployment cost, an integer linear programming model and a heuristic algorithm are designed. Numerical simulations verify that the cost-optimized design can significantly outperform the benchmark algorithm in terms of deployment cost and security level. Up to 25% cost saving can be achieved by deploying QKD with the hybrid trusted/untrusted relay scheme while keeping much higher security level relative to the conventional point-to-point QKD protocols that are only with the trusted relays.