As an emerging technology, Quantum Key Distribution (QKD) can provide information-theoretically secure keys for cryptographic purposes and it attracts worldwide attention. To extend its service capabilities from point-to-point communication to arbitrary remote communication parties, large-scale QKD network construction is underway. However, the dynamic and limited available resources of QKD networks remain a major obstacle to routing design. Numerous studies aim at designing routing schemes to maximize the overall network performance. While these routing schemes efficiently support end-to-end key relaying, their effectiveness diminishes when addressing diverse Quality of Service (QoS) requirements. In this paper, we propose an on-demand routing scheme with QoS provisioning to enhance end-to-end key relaying rates. Our scheme operates in two phases: an on-demand resource probing phase to dynamically update global network resource information and a routing decision phase that leverages a maximum flow model to optimize key relaying while satisfying rate-demand constraints. Simulation results on the SimQN platform demonstrate that the proposed scheme significantly improves end-to-end key relaying through-put and delay, providing effective QoS support for rate-demand QKD applications.
As an emerging technology, Quantum Key Distribution (QKD) can provide information-theoretically secure keys for cryptographic purposes and it attracts worldwide attention. To extend its service capabilities from point-to-point communication to arbitrary remote communication parties, large-scale QKD network construction is underway. However, the dynamic and limited available resources of QKD networks remain a major obstacle to routing design. Numerous studies aim at designing routing schemes to maximize the overall network performance. While these routing schemes efficiently support end-to-end key relaying, their effectiveness diminishes when addressing diverse Quality of Service (QoS) requirements. In this paper, we propose an on-demand routing scheme with QoS provisioning to enhance end-to-end key relaying rates. Our scheme operates in two phases: an on-demand resource probing phase to dynamically update global network resource information and a routing decision phase that leverages a maximum flow model to optimize key relaying while satisfying rate-demand constraints. Simulation results on the SimQN platform demonstrate that the proposed scheme significantly improves end-to-end key relaying through-put and delay, providing effective QoS support for rate-demand QKD applications.
Nowadays, Quantum Key Distribution (QKD) has garnered widespread attention due to its ability to provide symmetric secret keys with information-theoretic security in point-to-point communication. Additionally, key relay technology has been introduced to complete end-to-end key distribution between remote parties by consuming keys in the intermediate links. The routing problem of selecting paths for key relay technology becomes crucial as it directly impacts the network's performance. In this paper, we focus on addressing the routing problem for a specific scenario to serve applications with real-time requirements. Real-time is a critical necessity for supporting various applications, such as video chatting and calling. To satisfy real-time requirements and achieve Quality of Service (QoS) provision to guarantee the completion time, we introduce a distributed routing protocol called Distributed Routing Protocol Based on Key Reservation (Q-RoKR). It reserves keys in advance along the selected path, thereby satisfying real-time requirements. We also propose a priority-awareness mechanism to address resource competition and make efficient use of keys in links. Extensive experiments demonstrate that our protocol effectively meets the real-time requirements and significantly improves throughput. Furthermore, our key efficiency approaches the optimal bound when compared to other comparison schemes.
Quantum key distribution (QKD) is a symmetric key exchange mechanism designed to enhance the security of current communication systems. Although QKD provides unconditional security, it also comes with deployment challenges. One challenge is the distance limitation between the transmitter and receiver, which restricts the large-scale adoption of QKD. To overcome this, trusted relays are used as intermediate nodes, allowing QKD to evolve from distance-limited point-to-point connections to unlimited QKD networks (QKDN). With an increasing deployment of QKD and a growing number of applications requesting keys, quality of service (QoS) constraints must be set for efficient key resource management to alleviate the risk of rejecting application requests. In this work, we integrate key delivery delay and maximum requested key size as QoS constraints in a novel key allocation algorithm built on three QKDN layers – quantum, key management and service. Moreover, we design key relaying using quantum key pools and virtual quantum key pools as storage mechanisms. We use static and dynamic weights for relay path computation and evaluate their impact on the proposed key allocation strategies with QoS constraints and find that static weights show a good overall performance for QKDN, while performance with dynamic weights varies based on historical key consumption data.
As a technology of providing different service qualities to the different applications/users, QoS is a research hotspot in communication field. For quantum key distribution (QKD) networks which provide unconditional security for distribution of cryptographic keys, its unique characteristics, like extreme quantum key resource constraint and the different time requirements of secure key distribution, pose unprecedented challenges for the QoS support in QKD networks. In this paper, a service model is presented firstly, which includes three service classes with different distribution time requirements: key-guaranteed service, key-prioritized service and key-best-effort service. Then, a QoS-supported scheme is proposed to support this service model. Particularly, Quantum Key Reservation Approach (QKRA) is designed to reserve quantum keys for the key-guaranteed service. The simulation is conducted to investigate the performance of this QoS-supported scheme.
Quantum key distribution (QKD) can provide point-to-point information-theoretic secure key services for two connected users. In fact, the development of QKD networks needs more focus from the scientific community in order to broaden the service scale of QKD technology to deliver end-to-end secure key services. Of course, some recent efforts have been made to develop secure communication protocols based on QKD. However, due to the limited key generation capability of QKD devices, high quantum secure key utilization is the major concern for QKD networks. Since traditional routing techniques do not account for the state of quantum secure keys on links, applying them in QKD networks directly will result in underutilization of quantum secure keys. Therefore, an efficient routing protocol for QKD networks, especially for large-scale QKD networks, is desperately needed. In this study, an efficient routing protocol based on optimized link-state routing, namely QOLSR, is proposed for QKD networks. QOLSR considerably improves quantum key utilization in QKD networks through link-state awareness and path optimization. Simulation results demonstrate the validity and efficiency of the proposed QOLSR routing protocol. Most importantly, with the growth of communication traffic, the benefit becomes even more apparent.
In recent years, noticeable progress has been made in the development of quantum equipment, reflected through the number of successful demonstrations of Quantum Key Distribution (QKD) technology. Although they showcase the great achievements of QKD, many practical difficulties still need to be resolved. Inspired by the significant similarity between mobile ad-hoc networks and QKD technology, we propose a novel quality of service (QoS) model including new metrics for determining the states of public and quantum channels as well as a comprehensive metric of the QKD link. We also propose a novel routing protocol to achieve high-level scalability and minimize consumption of cryptographic keys. Given the limited mobility of nodes in QKD networks, our routing protocol uses the geographical distance and calculated link states to determine the optimal route. It also benefits from a caching mechanism and detection of returning loops to provide effective forwarding while minimizing key consumption and achieving the desired utilization of network links. Simulation results are presented to demonstrate the validity and accuracy of the proposed solutions.
ABSTRACT Quantum key relay over trusted relay nodes is a practical approach to overcoming the distance limitation of quantum key distribution (QKD) protocols in quantum-secured networking. However, the processing delay incurred by the quantum key relay function increases the quantum key response delay (KRD) which serves as a representative quality-of-service (QoS) metric for quantum-secured services. This QoS degradation becomes more pronounced in large-scale quantum-secured networks. To address this issue, we investigate a proactive quantum key relay algorithm that relays and prepares quantum keys for pairs of QKD nodes prior to requests for quantum-secured services. By jointly considering the length of the relay path, the available quantity of quantum keys, and the remaining lifetimes of the quantum keys, the proposed algorithm selects a pair of QKD nodes and performs proactive quantum key relay to establish a quantum key for the selected pair. The proposed algorithm enables more flexible operation by sequentially dividing the proactive quantum key relay algorithm into two parts: one for a relatively short distance pair of QKD nodes and the other for a long-distance pair of QKD nodes. The simulation results demonstrate that, compared with the on-demand quantum key relay algorithm, the proposed algorithm achieves a relative reduction of up to 89.7% in the modeled KRD, accompanied by a corresponding relative decrease of 13.9% in the provisioning ratio of quantum-secured service. Overall, these findings confirm the effectiveness of the proposed proactive quantum key relay algorithm in achieving short-latency quantum-secured networking.