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.
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.
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.
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.
With the advent of powerful quantum computers, an emerging quantum-resilient security mechanism within existing networks is crucial. Thus, Quantum Key Distribution (QKD), which generates symmetric secret keys with Information-Theoretical Security (ITS) for secure point-to-point communication, is present as a solution. Despite QKD’s potential, its deployment is challenging due to significant investment and infrastructure requirements. Using state-of-the-art technology, the maximum distance between nodes is limited to hundreds of kilometers, necessitating multiple nodes to relay keys. For now, QKD Network (QKDN) relies on software-defined networking (SDN) and a central orchestrator, but this centralized approach has limitations. Hence, the main challenge is to select an efficient path between key relays to avoid communication failure. To address these challenges, a more distributed approach could be envisioned. In this paper, we propose to leverage one of the distributed routing protocols, OSPF, to redefine and improve the current architecture. We propose a novel QKDN-based OSPF (Open Shortest Path First) architecture for efficient key relay routing, offering a completely different dimension to the overall network management: we modify QKDN architecture to exploit the OSPF networks and present a QKD-enabled OSPF version capable of computing the best path for key relay, offering a cost-effective and scalable solution for widespread QKD adoption.
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), based on the laws of physics rather than the computational \ncomplexity of mathematical problems, provides a secure way of establishing symmetrical binary \nkeys between two geographically distant users. The keys are secure from eavesdropping during \ntransmission and QKD ensures that any third party’s knowledge of the key is reduced to a \nminimum. In recent years, a noticeable progress in the development of quantum equipment has \nbeen reflected through a number of successful demonstrations of QKD technology. While they \nshow the great achievements of QKD, many practical difficulties still need to be resolved, such as \nto provide better service differentiation. These networks are characterized as being multihop in \nnature where the consumption key rate is often higher than the charging key rate, which means that \nthe links are available for a limited period of time only. Such features impose several challenges \non the effective modeling and evaluation of reliability as well as finding appropriate Quality \nof Service (QoS) solution. This thesis focuses on research in the field of QKD for securing \nreal-time communication by supporting QoS in QKD networks including a novel QoS model \nand novel distributed reactive routing protocol to achieve high-level scalability and minimize the \nconsumption of key material used for securing routing data. \nAs research in QKD networks grows larger and more complex, the need for highly accurate and \nscalable simulation technologies becomes important to assess the practical feasibility and foresee \ndifficulties in the practical implementation of theoretical achievements. Due to the specificity of \nQKD link which requires optical/quantum and Internet connection between the network nodes, it \nis very costly to deploy a complete testbed containing multiple network hosts and links to validate \nand verify a certain network algorithm or protocol. The network simulators in these circumstances \nsave a lot of money and time in accomplishing such task. A simulation environment offers the \ncreation of complex network topologies, a high degree of control and repeatable experiments, \nwhich in turn allows researchers to conduct exactly the same experiments and confirm their results. \nThis thesis describes the design and implementation of QKD network simulation module which \nwas developed in the network simulator of version 3 (NS-3). The module supports simulation \nof QKD network in overlay mode or in a single TCP/IP mode. Therefore, it can be used for \nsimulation of other network technologies regardless of QKD. \nImplemented simulation model was used for verification of proposed QoS solution. A number \nof simulations were performed. The obtained data have confirmed the primary thesis of this study, \nthat it is possible to use real-time applications in QKD networks.
Quantum key distribution (QKD) networks can provide information-theoretically secure key distribution between distant end nodes through key relaying. In QKD networks, the key relay protocol is vital since it provides the coordination specifications between nodes for key relaying and thus directly determines the performance, especially as the network scale expands. However, most existing protocols adopt a synchronous contend-and-relay approach, where the contention and consumption of quantum keys occur simultaneously, neglecting the storable nature of quantum keys and presenting significant challenges in reliability and quantum key utilization. To tackle these challenges, in this paper, we propose an asynchronous key relay protocol (AKRP). AKRP considers the storable nature of quantum keys, and adopts a reserve-then-relay approach to achieve lossless and zero-queuing key relaying through precise management of quantum keys and requests. On this basis, to further improve the performance of the proposed AKRP, we design two enhanced mechanisms, i.e., collision detection and resolution mechanism and multipath routing extension. The former enhances the consensus efficiency of AKRP and provides fine-grained key utilization on each link, and the latter utilizes quantum keys on possible relay paths and thus effectively copes with quantum key exhaustion. By conducting extensive experiments on a semi-physical real QKD network platform, results demonstrate that AKRP is superior to existing schemes in terms of end-to-end key throughput, quantum key consumption, and relaying latency.