Multicast is an important service type in both terrestrial and space communication networks but has security issues because more than one destination node can receive information. Point-to-point quantum key distribution can be achieved end-to-end over long distances by using a quantum satellite (e.g., Micius) as a relay node. Hence, how to provide secret keys for remote multicast services and efficiently distribute secret keys between the source node and multiple destination nodes for long-distance secure multicast services (SMSs) has become a critical problem. In this paper, a quantum satellite network with a special node structure is designed to complete point-to-multipoint key distribution, and a point-to-multipoint satellite relay scheme is proposed. The weight information of the link is dynamically described by the method of auxiliary topology, and a satellite relay tree is constructed. Finally, this paper proposes a satellite relay algorithm for multicast services to route and allocate key resources to solve the problem of long-distance point-to-multipoint key relay and improve the success probability of multicast service requests. Simulation results show that the proposed algorithm can improve the success probability of SMS requests by about 51.32% in a static scenario and 17.33% in a dynamic scenario.
Multicast is an important service type in both terrestrial and space communication networks but has security issues because more than one destination node can receive information. Point-to-point quantum key distribution can be achieved end-to-end over long distances by using a quantum satellite (e.g., Micius) as a relay node. Hence, how to provide secret keys for remote multicast services and efficiently distribute secret keys between the source node and multiple destination nodes for long-distance secure multicast services (SMSs) has become a critical problem. In this paper, a quantum satellite network with a special node structure is designed to complete point-to-multipoint key distribution, and a point-to-multipoint satellite relay scheme is proposed. The weight information of the link is dynamically described by the method of auxiliary topology, and a satellite relay tree is constructed. Finally, this paper proposes a satellite relay algorithm for multicast services to route and allocate key resources to solve the problem of long-distance point-to-multipoint key relay and improve the success probability of multicast service requests. Simulation results show that the proposed algorithm can improve the success probability of SMS requests by about 51.32% in a static scenario and 17.33% in a dynamic scenario.
Secure multicast services (SMSs), such as video conferences and multi-site backup of data centers, need to adopt multicast technology to transmit data among multiple parties with high demand for security. Quantum key distribution (QKD) is a promising technology for distributing information through theoretically secure secret keys. However, up to now, QKD has mainly focused on point-to-point distribution of quantum keys. In this study, what we believe to be a novel node structure is designed to support key multi-relay, and accordingly, a point-to-multipoint key relay scheme is put forward. An auxiliary topology is constructed to dynamically describe the connection and the weight between any two QKD nodes. Based on the auxiliary topology, a key-relay-tree-based routing-and-key assignment (KRT-RKA) algorithm is proposed and evaluated in static and dynamic scenarios. Simulation results show that the proposed algorithm has a higher security probability than the traditional scheme without a KR tree. Moreover, the performance of the KRT-RKA algorithm will be significantly improved as the number of destination nodes increases. In addition, the security of SMSs can be improved by increasing the density of the node distribution when KRT-RKA is applied.
In data center networks (DCNs), secure multicast provisioning services are obtained from data centers and transported to multiple users in a multicast style, which requires a high demand for security. Moreover, these services are usually stored and maintained in multiple geographically dispersed data centers for more reliable and efficient access. Quantum key distribution (QKD) is a state-of-the-art technology employed to unconditionally distribute security keys, based on the principles of quantum physics. Therefore, one should pay more attention to how to efficiently distribute global quantum keys in quantum DCNs in the near future. We investigate the problem of global QKD while leveraging multicast service backups among multiple geographically distributed datacenters for secure service provisioning. A distributed subkey-relay-tree-based, secure multicast scheme is proposed and used as a basis to develop a distributed subkey-relay-tree-based secure multicast-routing and key assignment algorithm. Numerical results show that the latter can achieve higher security probability and lower consumed keys compared with the traditional routing and key assignment scheme and single-key-relay-tree-based secure multicast scheme.
There is a need to ensure unconditionally secure communications between different sites of an organization. We use quantum key distribution (QKD) protocol to provide a continuous stream of secret key bits to each communicating pair for message encryption through one-time-pad (OTP) cryptography. Due to long distance between different sites, trusted nodes are used to relay each service key in a hop-by-hop manner from one end node to another end node of a communicating pair. In a QKD network, routes for key relaying can be affected by availability of relay key bits at trusted nodes. Also, relay key allocation among different routes can impact security. We consider the scenario of supporting multiple communicating pairs, where each pair demands delivery of a certain service key rate across the QKD network, and trusted nodes may not have sufficient relay key rates to perform bitwise encryption to protect the service key. Hence, there is a need to allocate the limited relay key bits to meet all service key delivery demands while considering its effects on security. We propose to perform jointly routing and relay key allocation to minimize attack success probability. We have formulated the joint problem as an optimization and further proposed an efficient algorithm to find the optimal solutions. We have evaluated the proposed algorithm to confirm its ability and efficiency in finding optimal routes and relay key allocations. For the specific network topology that we have adopted, results show that the minimum number of required trusted nodes increases linearly when end nodes are added to the system. Furthermore, we can achieve a higher security level by adding more trusted nodes in a QKD network. But increasing the number of trusted nodes beyond the minimum requirement may not continue to reduce significantly the attack success probability.
Quantum key distribution (QKD) has attracted much attention on secure communications across global networks. QKD over satellite networks can overcome the limitations of terrestrial optical networks, such as large attenuation over long distance fiber channel and difficulty of intercontinental domain communications. Different QKD networks (around the world) can intercommunicate through quantum satellites, leading to a global quantum network in near future. This raises a new resource allocation and management problem of QKD involving multiple satellite layers and distributed ground stations. Using existing schemes, a single satellite cannot perform QKD for ground stations for the whole day. Moreover, the research problem is more challenging due to limitations of satellite coverage: limited cover time of low earth orbit (LEO) satellite, high channel losses of geostationary earth orbit (GEO) satellite, etc. To overcome these limitations, our study proposes a double-layer quantum satellite network (QSN) implemented quantum key pool (QKP) to relay keys for ground stations. We propose a new architecture of trusted-repeater-based double-layer quantum satellite networks, comprising GEO and LEO satellites. We also address the routing and key allocation (RKA) problem for key-relay services over QSNs. We propose a novel joint GEO-LEO routing and key allocation (JGL-RKA) algorithm to solve the RKA problem. Simulative results show that the proposed scheme can increase success probability of key-relay services significantly. We also present the impact of different route selections mechanisms, number of satellite links, satellite node capability, and service granularity on network performance.
Quantum key resources in quantum satellite networks are fundamental to confidential data forwarding, which highly depends on the network topology. In this paper, we propose a network topology construction scheme via formulating the dynamic link establishment among network nodes as an integer linear programming to maximize the number of available quantum keys in the topology. Then we solve this topology optimization problem through subgradient method based on the Lagrange duality theory. Under the optimized topology, we further propose a key-based routing and resource allocation (KRRA) algorithm to forward secret keys for ground stations. The simulation results show that our scheme performs better than the benchmark method with the minimum route distance in terms of the number of quantum keys and the success probability of real-time secret key forwarding service.
Free-space long-distance quantum key distribution (QKD) has the characteristics of low attenuation and wide coverage, which can overcome the limitation of transmission distance based on ground optical fiber QKD networks. Long-distance QKD requests can be relayed by quantum satellites to achieve intercontinental QKD. At present, there is only one quantum satellite in space, quantum satellite network with multiple quantum satellites is necessary to be deployed to cover the global. Thus, how to construct the quantum satellite network becomes a new challenge. In this paper, we propose a centralized and distributed collaborative scheme of quantum satellite network. Low-Earth-orbit (LEO) quantum satellites, as important relay satellites, will affect the performance of the global QKD network. Based on the above architecture, we analyze the influence of the structure of LEO quantum satellite constellation on the QKD performance. Simulation results show that the key relay performance of the constellation is related to the form of inter-satellite link. and the more the number of satellites is, the greater the successful probability of the key relay services will be.