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.
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.
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 currently being explored as a solution to the threats posed to current cryptographic protocols by the evolution of quantum computers and algorithms. However, single-photon quantum signals used for QKD permit to achieve key rates strongly limited by link performance (e.g., loss and noise) and propagation distance, especially in multi-node QKD networks, making it necessary to design a scheme to efficiently and timely distribute keys to the various nodes. In this work, we introduce the new problem of joint Routing, Channel, Key-rate and Time-slot Assignment (RCKTA), which is addressed with four different network settings, i.e., allowing or not the use of optical bypass (OB) and trusted relay (TR). We first prove the NP-hardness of the RCKTA problem for all network settings and formulate it using a Mixed Integer Linear Programming (MILP) model that combines both quantum channels and quantum key pool (QKP) to provide an optimized solution in terms of number of accepted key rate requests and key storing rate. To deal with problem complexity, we also propose a heuristic algorithm based on an auxiliary graph, and show that it is able to obtain near-optimal solutions in polynomial time. Results show that allowing OB and TR achieves an acceptance ratio of 39% and 14% higher than that of OB and TR, respectively. Remarkably, these acceptance ratios are obtained with up to 46% less QKD modules (transceivers) compared to TR and only few (less than 1 per path) additional QKD modules than OB.
With quantum computing advancing, traditional encryption risks cracking, making quantum key distribution (QKD) crucial for its quantum-physics-based unconditional security. Large-scale QKD networks face high key consumption, uneven allocation, and reduced long-distance generation rates. This paper proposes MTSA, a time slot allocation-based multi-path routing scheme using linear programming and SDN for load balancing, with a two-level cache queue and optimized polling algorithm. Simulations on NSFNET/USNET show MTSA boosts key utilization by 15.565% and distribution success rate by 12.534%, optimizing QKD network performance.
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%.
Quantum secure communication networks based on quantum key distribution (QKD) technology are gradually improving, which can provide remote and networked key services for multiple users. This paper proposes a key distribution solution for latency and resource optimization in trusted relay QKD networks. In this scheme, the key distribution process between trusted relay nodes is presented as a joint optimization problem by considering the constraints of service delay, bandwidth, path resource consumption, quality loss and remaining quantum key quantity. In this paper, we treat key distribution as a bi-objective minimization problem, maintaining a trade-off between service delay and path resource consumption. Specifically, we propose a dynamic key distribution framework based on linear programming and particle swarm optimization. Simulation results show that the key distribution path selection in this scheme can be adjusted according to the service delay, key quality, and path resource consumption. Compared with the Random and customized OSPF policies, this scheme has higher performance. More specifically, the solution reduced average service latency by 27% while reducing path resource consumption by 560%.
Optical network security has attracted extensive attentions recently, data encryption is an effective way to enhance the security. Unlike conventional key distribution methods, Quantum key distribution (QKD) is provably-secure. Integrating QKD into optical networks can provide a new paradigm for secure communications. In a QKD integrated optical network, besides the traditional data channels, two additional channels, called quantum-signal channels and public interaction channels, are required to support secure key. Crucially, how to optimally allocate limited wavelength resources to the three channels is emerging as a novel problem. By introducing wavelength division multiplexing (WDM) network and defining the wavelength occupancy factor, this paper designs a dynamic routing, wavelength and time-slot allocation (DRWTA) algorithm for the wavelength allocation in QKD integrated optical network. The simulation results show wavelength scale factor has an adverse effect on the resource utilization rate and the blocking probability. Furthermore, the DRWTA algorithm provides a strategy to allocate wavelength for three types of channels in QKD-WDM networks. The success probability can be improved by exploiting the DRWTA algorithm.