For the security requirements of high-speed and large-capacity transmission, quantum key distribution technology plays an important role in optical networks. In the process of deploying QKD networks in the future, the partially- trusted QKD network will be a more realistic scenario. To solve the QKD with an untrusted relay, MDI-QKD protocol is designed, In MDI-QKD, two QKD nodes send the quantum states to the untrusted relay and the measurement device in the untrusted relay measures the received quantum states. Based on the overall feasibility of QKD-integrated optical networks and the common tree topologies in backbone optical networks, this paper proposes a quantum key distribution method and a routing algorithm in a partially-trusted QKD tree-topology network by combining the trusted relay technology and MDI- QKD protocol and considering the quantum key pool. Simulation results show that the proposed TT-AR algorithm is effective for tree topologies.
For the security requirements of high-speed and large-capacity transmission, quantum key distribution technology plays an important role in optical networks. In the process of deploying QKD networks in the future, the partially- trusted QKD network will be a more realistic scenario. To solve the QKD with an untrusted relay, MDI-QKD protocol is designed, In MDI-QKD, two QKD nodes send the quantum states to the untrusted relay and the measurement device in the untrusted relay measures the received quantum states. Based on the overall feasibility of QKD-integrated optical networks and the common tree topologies in backbone optical networks, this paper proposes a quantum key distribution method and a routing algorithm in a partially-trusted QKD tree-topology network by combining the trusted relay technology and MDI- QKD protocol and considering the quantum key pool. Simulation results show that the proposed TT-AR algorithm is effective for tree topologies.
Quantum Key Distribution (QKD) is a promising technology that provides proven unconditional security based on fundamentals of quantum physics, especially for point-to-point communications. It could be applied in large-scale optical networks for long-distance key provisioning mainly by three relaying methods: quantum-repeater-based QKD, trusted-relay-based QKD, and measurement-device-independent QKD (MDI-QKD). However, quantum-repeater-based QKD is still under study because of the immature technologies such as the preliminary quantum memory. The trusted-relay-based QKD is vulnerable since insecurity of non-ideal single-photon sources and detectors cannot be ignored in practical applications. On the other hand, for MDI-QKD, there exists a limitation on its key rate under long-distance communications. According to these limitations, embedding protocols like MDI-QKD into the existing trusted-relay-based QKD secured optical networks (QKD-ON) with usage of untrusted relays is a promising key-provisioning scheme. In this paper, we study such partially-trusted relay scenarios and focus on its routing of keys in different kinds of typical network topologies. A partially-trusted-relay-based QKD method is described, which can allow a pair of optical nodes sharing secret keys under the coexistence of trusted relays and untrusted relays. The secret-key provisioning with collaborative routing (SKP-CR) algorithm is proposed to search for the optimal key-relay routing path. We perform the simulations with different proportion of trusted relays versus untrusted relays, initial secret keys in the quantum key pools (QKPs), and traffic load. The simulations verify that theSKP-CRalgorithm can significantly outperform the conventional trusted-relay-based scheme in terms of key-distribution success rate with an improvement of up to62%with a mesh topology.
Quantum key distribution (QKD) can protect the exchange process of confidential information between communicating parties. By using the basic principles of quantum mechanics and combined with “one-time pad” cipher encryption, information can be unconditionally secure. The BB84 protocol first describes the method of transmitting information by photon polarization state, and it expounds the transmission process of services between trusted relays. However, due to the defects of real experimental devices, there are security vulnerabilities in QKD in a real system. The birth of measurement-device-independent quantum key distribution (MDI-QKD) protocol solves the problem, providing immunity to hacker attacks at the end of the detector. It can enable both sides of the transmission service to establish a connection and generate secret keys through an untrusted relay node to ensure information security. However, the types and properties of link nodes in quantum key distribution network (QKDN) based on partially trusted relay are more complex, which can easily result in network fault. Therefore, how to prevent the impact of failure on QKDN has become an urgent problem. In this paper, we propose a protection scheme for QKDN with partially trusted relays. The method deals with trusted and untrusted relays differently and constructs the working and protection paths of the secret key for each service. It reduces resource conflict between the protection and working paths by establishing a key protection threshold, which realizes the resource trade-off between the two factors. Simulation results show that the scheme provides effective protection to the services, and it improves the stability and reliability of QKDN based on partially trusted relay.
The long-distance transmission of quantum secret key is a challenge for quantum communication. As far as the current relay technology is concerned, the trusted relay technology is a more practical scheme. However, the trusted relay technology requires every relay node to be trusted, but in practical applications, the security of some relay nodes cannot be guaranteed. How to overcome the security problem of trusted relay technology and realize the security key distribution of remote quantum network has become a new problem. Therefore, in this paper, a method of quantum key distribution in ring network is proposed under the condition of the coexistence of trusted and untrusted repeaters, and proposes a partially-trusted based routing algorithm (PT-RA). This scheme effectively solves the security problem of key distribution in ring backbone network. And simulation results show that PT-RA can significantly improve key distribution success rate compared with the original trusted relay technology.
Quantum key distribution (QKD) has demonstrated a great potential to provide future-proofed security, especially for 5G and beyond communications. As the critical infrastructure for 5G and beyond communications, optical networks can offer a cost-effective solution to QKD deployment utilizing the existing fiber resources. In particular, measurement-device-independent QKD shows its ability to extend the secure distance with the aid of an untrusted relay. Compared to the trusted relay, the untrusted relay has obviously better security, since it does not rely on any assumption on measurement and even allows to be accessed by an eavesdropper. However, it cannot extend QKD to an arbitrary distance like the trusted relay, such that it is expected to be combined with the trusted relay for large-scale QKD deployment. In this work, we study the hybrid trusted/untrusted relay based QKD deployment over optical backbone networks and focus on cost optimization during the deployment phase. A new network architecture of hybrid trusted/untrusted relay based QKD over optical backbone networks is described, where the node structures of the trusted relay and untrusted relay are elaborated. The corresponding network, cost, and security models are formulated. To optimize the deployment cost, an integer linear programming model and a heuristic algorithm are designed. Numerical simulations verify that the cost-optimized design can significantly outperform the benchmark algorithm in terms of deployment cost and security level. Up to 25% cost saving can be achieved by deploying QKD with the hybrid trusted/untrusted relay scheme while keeping much higher security level relative to the conventional point-to-point QKD protocols that are only with the trusted relays.
This study proposes a group key service node placement method for quantum key distribution (QKD) networks based on partially trusted relays, aiming to optimize network structure, improve key distribution efficiency, reduce communication delay, and ensure transmission integrity and confidentiality. Based on graph theory, a key information model for the quantum key distribution network is established, which defines node types, functions, and connectivity. Leveraging the secure transmission protocol of quantum keys, the unconditional security of the key during transmission is ensured. Furthermore, this study proposes a QKD network architecture incorporating partially trusted relays, which combines trusted and untrusted relay technologies. An improved p-median model is introduced and solved using a greedy algorithm to ensure secure quantum key distribution and optimal deployment of group key service nodes. Experimental results demonstrate that the location of group key service nodes in quantum key distribution network ensures the minimum number of key service nodes and minimizes the path length from network demand nodes to group key service nodes. Furthermore, this method significantly improves the key distribution efficiency, success rate, security, energy consumption, resource consumption, network coverage, and blind area of quantum key distribution network.
Quantum Key Distribution (QKD) has demonstrated unique and significant advantages in secure communication. In particular, Measurement-Device-Independent QKD (MDI-QKD), which is independent of measurement devices, increases data transmission distances and addresses the issue of low security in trusted relays. Therefore, in this work, we investigate QKD networks based on trusted and untrusted relays over optical backbone networks, providing a cost-optimal solution for the deployment and implementation of QKD networks. Specifically, this paper describes the QKD network and defines a new cost model, which not only fully considers the diverse impact factors of deployment costs but also meets the requirements for sharing network elements in response to different QKD chain requests. Based on cost model, this paper further proposes a cost-optimal heuristic algorithm for hybrid QKD network deployment, which can provide an economical and secure deployment solution for QKD networks. Extensive simulation experiments are conducted and the experimental results show that the proposed method outperforms current mainstream QKD network deployment algorithms in both deployment cost and security. Moreover, as the network scale increases, the advantages of our algorithm become more pronounced. Compared to mainstream algorithms, our method achieve an improvement of 17.7% -64.3% in cost savings and 1.19 to 3.24 times in security levels.