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.
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) is a technology that can resist the threat of quantum computers to existing conventional cryptographic protocols. However, due to the stringent requirements of the quantum key generation environment, the generated quantum keys are considered valuable, and the slow key generation rate conflicts with the high-speed data transmission in traditional optical networks. In this paper, for the QKD network with a trusted relay, which is mainly based on point-to-point quantum keys and has complex changes in network resources, we aim to allocate resources reasonably for data packet distribution. Firstly, we formulate a linear programming constraint model for the key resource allocation (KRA) problem based on the time-slot scheduling. Secondly, we propose a new scheduling scheme based on the graded key security requirements (GKSR) and a new micro-log key storage algorithm for effective storage and management of key resources. Finally, we propose a key resource consumption (KRC) routing optimization algorithm to properly allocate time slots, routes, and key resources. Simulation results show that the proposed scheme significantly improves the key distribution success rate and key resource utilization rate, among others.
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%.
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.
As the foundation of quantum secure communication, the quantum key distribution (QKD) network is impossible to construct by using the operation mechanism of traditional networks. In the meantime, most of the existing QKD network routing schemes do not fit some specific quantum key practicality scenarios. Aiming at the special scenario of high concurrency and large differences in application requirements, we propose a new quantum key distribution network routing scheme based on application priority ranking (APR-QKDN). Firstly, the proposed APR-QKDN scheme comprehensively uses the application's priority, the total amount of key requirements, and the key update rate for prioritizing a large number of concurrent requests. The resource utilization and service efficiency of the network are improved by adjusting the processing order of requests. Secondly, the queuing strategy of the request comprehensively considers the current network resource situation. This means the same key request may adopt different evaluation strategies based on different network resource environments. Finally, the performance of the APR-QKDN routing scheme is compared with the existing schemes through simulation experiments. The results show that the success rate of application key requests of the APR-QKDN routing scheme is improved by at least 5% in the scenario of high concurrency.
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.
Currently, with the continuous advancement of network and communication technology, the amount of data carried by the optical network is very huge. The security of high-speed and large-capacity information in optical networks has attracted more and more attention. Quantum key distribution (QKD) provides information-theoretic security based on the laws of quantum mechanics. Introducing QKD into an optical network can greatly improve the security of the optical network. In order to reduce the cost of deployment on QKD infrastructure, quantum signals in QKD and classical signals in optical networks are multiplexed in the same fiber by wavelength-division manner. Moreover, due to the limited wavelength resources in an optical fiber, time-division technology is adopted to construct different kinds of channels in QKD system for efficient utilization of wavelength resources. Under such situation, how to satisfy the security requirements of service requests and complete the efficient scheduling of multi-dimensional resources, i.e., wavelengths and timeslots, is a challenging problem. This paper addresses this problem by considering multi-dimensional routing, wavelength, and timeslot allocation (RWTA) in short-distance quantum key distribution optical networks (QKD-ON), in which any two nodes can directly establish a quantum channel, and the maximum distance between any two nodes is less than the distance that can carry out point-to-point quantum key distribution process. While accommodating services with security requirements in QKD optical networks, to avoid the wavelength time-slot fragmentation caused by the constraints of wavelength consistency and time-slot continuity, we propose a time-window-based security orchestration strategy as well as relative-loss of time continuous compactness based RWTA strategy. We conducted the simulations under various scenarios, e.g., different key updating periods and different distributions on wavelength resources, etc., and the results show that the proposed strategy can achieve better performance compared with the baselines in terms of key success rate, key-updating delay, and blocking probability.