| Nowadays,safeguarding network information security has become an important strategic task related to national economic development,social stability and even national security.Quantum key distribution(QKD)is an essential branch of quantum communication,which is of great significance to promote the development of strategic emerging industries and enhance national security power.QKD network is a new network paradigm centered on QKD technology,which has opened up a new path for ensuring network information security.This thesis focuses on the pivotal technologies of QKD networking and application,which carries out research from four perspectives:key storage,key relay,key supply,and key service.Aiming at the four core challenges of "flexibility,economy,efficiency,and intelligence" for QKD networking and application,this thesis mainly accomplishes four technical innovations on "flexible key pool construction technique,cost-optimized relay deployment technique,efficient multi-tenant provisioning technique,and software-defined intelligent service technique" of QKD networks.The scientific issue of "optimal adaptation between low bit rate key resources and multi-service key requirements" has been tackled,offering theoretical support for the scalable,highly flexible and low latency applications of QKD networks,bridging the research shortcomings in this field,as well as enhancing the intelligence level of QKD networks.The major works and innovations are summarized as follows:First,from the perspective of "key storage",how to facilitate the flexible construction of key pools in a QKD network,in order to improve the flexibility of key storage and increase the success probability of key pool construction?The QKD network flexible key pool construction technique has been studied,where a time-scheduled quantum key pool(QKP)construction method is proposed.By dividing the wavelength/fiber channel resources into finer time/wavelength/fiber channel resources through the slicing manner,the flexible construction of QKPs over optical fiber networks is realized.An integer linear programming model and a joint path/link-based routing,wavelength and time-slot allocation algorithm are designed for time-scheduled QKP construction.The problems of fixed/flexible key consumption,uniform/non-uniform time-slot allocation,etc.,are analyzed.Moreover,the correlation between the QKP construction success probability and multiple parameters is explored,enabling the flexible improvement of QKP construction success probability up to 100%.Second,from the perspective of "key relay",how to perform the cost optimization for multi-relay deployment of QKD networks,in order to reduce the cost of key relay and enhance the network security level?The QKD network cost-optimized relay deployment technique has been studied,where the QKD networking schemes are proposed for the cost optimization of trusted relay deployment and hybrid relay deployment.For the trusted relay networking scenario,by formulating the cost model of trusted relay-based networks,as well as designing the integer linear programming model and the heuristic algorithm,the cost optimization strategy for trusted relay-based QKD networks is proposed.The optimal deployment of trusted relays with 31%cost saving relative to the benchmark algorithm(i.e.,random routing and channel allocation)can be achieved.For the hybrid relay networking scenario,by formulating the cost and security models of hybrid relay-based networks,as well as designing the heuristic algorithm,the cost optimization strategy for hybrid relay-based QKD networks is proposed.Compared to the trusted relay scheme,the hybrid relay scheme can achieve up to 25%cost saving and 115%security level enhancement.Third,from the perspective of "key supply",how to achieve efficient provisioning of multiple tenants in a QKD network,in order to increase the efficiency of key supply and reduce the tenant-request blocking probability?The QKD network efficient multi-tenant provisioning technique has been studied,where the strategies for efficient provisioning of offline multi-tenancy and online multi-tenancy are pioneered.For the offline multi-tenancy scenario,the offline multi-tenant key rate sharing scheme is designed,while an offline multi-tenant key assignment algorithm is proposed.The joint improvement mechanism of the offline tenant-request success probability and network-wide key resource utilization is revealed,achieving a high balance between key resource supply and offline multi-tenant key demand.For the online multi-tenancy scenario,the random,fit,and best-fit based online multi-tenant provisioning algorithms are designed.Moreover,a reinforcement learning-based efficient online multi-tenant provisioning solution is proposed,which can achieve up to 60%reduction in online tenant-request blocking probability,and 8.96%improvement in network-wide key resource utilization compared to the three heuristics.Fourth,from the perspective of "key service",how to accomplish the on-demand customization of QKD network services,in order to enhance the intelligence of key service and reduce the control latency of QKD services?The QKD network software-defined intelligent service technique has been studied,where a software-defined QKD as a service(QaaS)architecture is proposed.More specifically,a control framework for software-defined QaaS is devised,while the protocol extension,cross-layer interaction flow,as well as routing and key allocation strategy are presented for software-defined QaaS implementation.A software-defined QaaS network experimental testbed is established,which tests and verifies that the software-defined control technique is beneficial to improve the intelligence level of key service,while the control latency of QKD services has been reduced from second level to millisecond level.This work realizes the intelligent creation,modification,and deletion of QKD services with software-defined control technique,laying the foundation for QKD intelligent networking and low latency applications. |
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