With the continuous development of quantum computing technology, Quantum Key Distribution (QKD) is an important means of secure communication in the post-quantum era. However, the high cost of trusted routing relays in QKD networks has hindered its widespread adoption in power systems. Reducing costs is the key to the popularization of QKD in large-scale data grid scenarios. Therefore, this paper proposes a routing scheme for QKD network in a hybrid trusted environment. Our scheme is based on SDN architecture, utilizing the characteristics of QKD network in hybrid trusted environment, through prioritizing the selection of trusted paths (composed entirely of trusted quantum nodes) and backup selection of hybrid trusted paths (composed of both trusted and semi-trusted quantum nodes), implementing a unified dynamic routing strategy to obtain the optimal quantum routing path. Furthermore, by collecting topology information and real-time link status of the power grid, a calculation method for the number of paths and link costs is proposed to maximize load balancing in the network. Finally, the simulation results demonstrate that our scheme outperforms routing schemes relying solely on trusted quantum nodes for key distribution, as well as other cooperative routing schemes involving semi-trusted quantum nodes, in terms of success rate of distribution and load balancing.
With the continuous development of quantum computing technology, Quantum Key Distribution (QKD) is an important means of secure communication in the post-quantum era. However, the high cost of trusted routing relays in QKD networks has hindered its widespread adoption in power systems. Reducing costs is the key to the popularization of QKD in large-scale data grid scenarios. Therefore, this paper proposes a routing scheme for QKD network in a hybrid trusted environment. Our scheme is based on SDN architecture, utilizing the characteristics of QKD network in hybrid trusted environment, through prioritizing the selection of trusted paths (composed entirely of trusted quantum nodes) and backup selection of hybrid trusted paths (composed of both trusted and semi-trusted quantum nodes), implementing a unified dynamic routing strategy to obtain the optimal quantum routing path. Furthermore, by collecting topology information and real-time link status of the power grid, a calculation method for the number of paths and link costs is proposed to maximize load balancing in the network. Finally, the simulation results demonstrate that our scheme outperforms routing schemes relying solely on trusted quantum nodes for key distribution, as well as other cooperative routing schemes involving semi-trusted quantum nodes, in terms of success rate of distribution and load balancing.
Since the QKD network can overcome the distance limitation and expand the point-to-point QKD system to a multi-user key distribution system, some testing QKD networks have been built. However, all of this previous research seldom focused on the routing mechanism of QKD network in detail. Therefore, this paper focuses on the routing issue in trust relaying QKD network, builds a model of the trust relaying QKD network and proposes a secret-key-aware routing method. In our method, a dynamic model for the residual local key is proposed to forecast the residual local key quantity of each QKD link more accurately, and the cost of QKD link and relaying path are defined by multiple affecting factors, e.g. the generation, consumption rate and the local key depletion index. The proposed method is implemented and evaluated in a simulation environment. The simulation results show that our routing method can increase the success rate of key exchange, make all the QKD links participate key exchange with almost equal opportunity to achieve load balance, and trade off the local key generation and consumption of each QKD link. Therefore, our proposed method can contribute to effectively improve the holistic performance of the trust relaying QKD network.
With the development of quantum computing and computer science, the risk of traditional cryptographic algorithms being cracked is increasing. Therefore, quantum key distribution (QKD) technology based on quantum physical properties has been developed to ensure the security of information communication. Large-scale QKD networks can be built using trusted relay technology, but the hops encryption and decryption process of trusted relay will consume extra keys, which makes it particularly important to choose a reasonable path to reduce the consumption of extra keys during key distribution. The existing routing algorithms mainly focus on the number of remaining keys and hops, but ignore the congestion information of the network, resulting in a high key exchange failure rate and an increase in key consumption. In view of this background, we propose a load balancing routing (LBR) algorithm, which can realize congestion control in QKD network by dynamically detecting link state with SDN controller. Simulation results show that LBR improves key request success rate by more than 10% and key utilization efficiency by about 5% compared with existing methods.
Hybrid-trusted Quantum Key Distribution (QKD) networks face unique security challenges due to semi-trusted nodes. These nodes may introduce security threats such as man-in-the-middle attacks and key storage side-channel leakage. With the increasing complexity of QKD network architectures and expanding application scenarios, substantial divergences have emerged between user requirements for communication duration and cryptographic security demands. To address security challenges in hybrid-trusted QKD environments and provide differentiated services for users with varying requirements, this paper proposes a Service Requirement-based Hybrid-Trusted QKD Network (SRHT-QKDN) routing scheme. We propose a time-slot allocation model for QKD that employs time-slot resources as substitutes for key-generation resources in resource allocation processes. For sustained key distribution required by prolonged communications, the scheme implements two distinct time slot allocation algorithms: continuous-consistent and discrete-inconsistent allocation, enabling periodic quantum key updates. Concurrently, QKD requests are classified into three security levels, with corresponding routing strategies developed for each tier to achieve security service differentiation while maintaining routing success rates. Simulations conducted under four distinct operational conditions demonstrate that the SRHT-QKDN routing scheme not only effectively fulfills key continuity requirements but also achieves optimal overall performance in request success rate and security assurance, outperforming two benchmark routing schemes.
Quantum Key Distribution (QKD) networks enable unconditionally secure key exchange using quantum mechanical principles. However, routing cryptographic keys across multi-hop quantum networks introduces challenges unique to quantum communication. This survey analyzes and classifies 26 routing strategies proposed between 2013 and 2024 for terrestrial, satellite, and hybrid QKD infrastructures. Dynamic, key-aware routing algorithms have been shown to reduce service rejection rates by 25-40% compared to static shortest-path methods by incorporating real-time key pool availability and link error rates. Multi-path strategies improve resilience against trusted-node compromise by distributing keys across disjoint routes, albeit with an increase in key consumption of 30-60%. SDN-based orchestration frameworks emerge as essential enablers of flexible, QoS-aware routing for hybrid networks integrating terrestrial fibers and intermittent satellite links. Critical research directions include reducing dependence on trusted nodes through quantum repeaters or post-quantum cryptography, developing standardized key management interfaces for interoperability, and adopting AI-driven predictive routing for adapting to fluctuating network states. This comprehensive synthesis of routing algorithms, performance trade-offs, and unresolved issues offers practical guidance for engineering secure, adaptable, and large-scale QKD networks capable of meeting real-world deployment demands.
In this paper, we consider hybrid quantum key distribution (QKD) networks with primarily quantum repeaters and a small number of trusted nodes. While the trusted nodes need to be trusted, the use of such nodes, together with efficient routing algorithms, can significantly improve the key generation rate. We show that when trusted nodes are placed at asymmetric locations relative to Alice and Bob, however, existing routing algorithms can lead to low key rate. To address this issue, we develop dynamic routing strategies that adjust routing decisions based on the current key pool conditions in the network. In addition, we investigate new and existing classical post-processing techniques that complement the dynamic routing strategies. Using extensive simulations, we show that our dynamic routing strategies can significantly outperform static strategies, and the post-processing techniques are beneficial in high noise scenarios. In addition, combining the dynamic routing strategies and post-processing techniques can further improve the overall key rate.
To ensure the security of information exchange in software-defined optical networks, quantum key distribution (QKD) based on quantum mechanics is introduced. However, the slow and valuable process of generating quantum key resources contradicts the high-speed data transmission requirements of optical networks. To address this issue, this paper proposes the CPSR-HQKDN scheme, which takes into account factors such as security requests, key demand, key residual, and key update rates for trusted and untrusted links. This approach improves resource utilization and service efficiency by optimizing the processing order of key requests. Moreover, the routing strategy dynamically adjusts based on the network resource environment, thereby increasing the success rate of key requests. Through simulation experiments comparing the performance of the CPSR-HQKDN routing scheme with existing schemes, it is observed that in high-concurrent scenarios, the CPSR-HQKDN routing scheme can improve the success rate of key requests by at least 5%.