Quantum Key Distribution (QKD) provides unconditional peer-to-peer security based on the principles of quantum physics. By utilizing relay nodes, the security of QKD can be extended over longer distances. However, the introduction of relay nodes brings both security and communication success rates issues. To tackle those issues we propose an enhanced multi-path scheme. The key features of our proposal are as follows: 1. By taking the reliability of relay nodes as one of the algorithm inputs,making the scheme more suitable for partially trusted QKD (PTQKD) networks. 2. By using Multi-Segment Multi-Path approach increases the difficulty for attackers to obtain complete key information and improves the security of PTQKD. 3. The adaptive routing algorithm generates a sufficient number of diverse paths based on node contribution rate, key freshness, and reliability. We conducted a theoretical analysis of the algorithm,and simulation results on PTQKD demonstrate that our method outperforms traditional QKD methods in terms of security and transmission success rate. This advancement has the potential to enhance the adoption of QKD networks.
Quantum Key Distribution (QKD) provides unconditional peer-to-peer security based on the principles of quantum physics. By utilizing relay nodes, the security of QKD can be extended over longer distances. However, the introduction of relay nodes brings both security and communication success rates issues. To tackle those issues we propose an enhanced multi-path scheme. The key features of our proposal are as follows: 1. By taking the reliability of relay nodes as one of the algorithm inputs,making the scheme more suitable for partially trusted QKD (PTQKD) networks. 2. By using Multi-Segment Multi-Path approach increases the difficulty for attackers to obtain complete key information and improves the security of PTQKD. 3. The adaptive routing algorithm generates a sufficient number of diverse paths based on node contribution rate, key freshness, and reliability. We conducted a theoretical analysis of the algorithm,and simulation results on PTQKD demonstrate that our method outperforms traditional QKD methods in terms of security and transmission success rate. This advancement has the potential to enhance the adoption of QKD networks.
Quantum key distribution (QKD), a key application of quantum information technology and “one-time pad” (OTP) encryption, enables secure key exchange with information-theoretic security, meaning its security is grounded in the laws of physics rather than computational assumptions. However, in QKD networks, achieving long-distance communication often requires trusted relays to mitigate channel losses. This reliance introduces significant challenges, including vulnerabilities to compromised relays and the high costs of infrastructure, which hinder widespread deployment. To address these limitations, we propose a zero-trust spatiotemporal diversification framework for multipath–multi-key distribution. The proposed approach enhances the security of end-to-end key distribution by dynamically shuffling key exchange routes, enabling secure multipath key distribution. Furthermore, it incorporates a dynamic adaptive path recovery mechanism that leverages a recursive penalty model to identify and exclude suspicious or compromised relay nodes. To validate this framework, we conducted extensive simulations and compared its performance against established multipath QKD methods. The results demonstrate that the proposed approach achieves a 97.22% lower attack success rate with 20% attacker pervasiveness and a 91.42% reduction in the attack success rate for single key transmission. The total security percentage improves by 35% under 20% attacker pervasiveness, and security enhancement reaches 79.6% when increasing QKD pairs. Additionally, the proposed scheme exhibits an 86.04% improvement in defense against interception and nearly doubles the key distribution success rate compared to traditional methods. The results demonstrate that the proposed approach significantly improves both security robustness and efficiency, underscoring its potential to advance the practical deployment of QKD networks.
As a promising application of quantum information technology, Quantum Key Distribution (QKD) can provide information-theoretically secure key exchange for adjacent communication parties. To achieve long-distance secure communication and scale expansion against inherent channel loss, trusted relays, which are assumed to be absolutely secure, are introduced into QKD networks. However, in practice, trusted relays may be compromised by attacks from ubiquitous eavesdroppers even protected by powerful hardware. Thus, how to ensure the security of end-to-end key distribution in partially-trusted relay QKD networks with the coexistence of trusted relays and untrusted relays becomes a challenging but urgent problem to be solved. To address this critical problem, in this article, we design a segment-based multipath key distribution method. The basic idea of the method is to maximize the security of the end-to-end key distribution through the segment-based multipath key distribution. Under the premise of security level requirements, we further propose a flexible key reconstruction scheme to improve the efficiency of key distribution and obtain available secret keys as many as possible. The extensive simulations are conducted and the results reveal that our method significantly outperforms the traditional multipath QKD method in terms of both security and efficiency.
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) protocols generate a same secret key at two nodes which are at different locations. Such key is used to encrypt and decrypt messages for unconditionally secure communications through a classical channel. Originally, QKD protocols are designed to work between two nodes which are directly connected through a point-to-point quantum channel. Currently, commercial QKD systems have limited range and key rate. To increase key rate and extend range, the key generated by QKD at one end node is relayed hop-by-hop to the other end node through multiple trusted nodes. In a QKD network with multiple pairs of communicating nodes, routing deals with the issue of deciding for each pair, which trusted nodes are used to form a path connecting the end nodes. This paper presents an overview of QKD and highlights the differences between QKD routing as compared to classical routing. The challenges of QKD routing are presented. Existing works dealing with the challenges are surveyed. This paper ends with a discussion on remaining research issues.
Quantum key distribution (QKD) provides information-theoretic security based on quantum mechanics, and as quantum key distribution becomes increasingly practical, questions of how to employ it effectively over largescale networks and large distances becomes increasingly important. In this work, we investigate the B92 entanglement based QKD protocol and a five-layer QKD network architecture consisting of trusted relay nodes. Previous research seldom focused on the ground routing mechanism of QKD networks in detail. Since no intersecting links are beneficial to reducing the key consumption rate and improving link security, combined with the core idea of reducing the number of link relay hops, we propose a minimum path cost multi-path routing algorithm for no intersecting links in quantum key distribution networks. By analyzing the security of the link, we effectively reduce the number of relay nodes and the number of relay links that pass through and give priority to the routing scheme with the minimum number of hops in the number of relay hops, which avoids the congestion and waste caused by the existence of interleaved multi-path in traditional multi-path routing. Meanwhile, the scheme effectively improves the quality of service index, avoids the generation and consumption of redundant keys, and reduces the waste of quantum key resources.
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.