###### Abstract  
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. q 2025 9 76  
Academic Editor: [PERSON]  
31 December 2024  
Revised: 12 March 2025  
Accepted: 17 March 2025  
Published: 26 March 2025  
**Citation:** [PERSON]; [PERSON]; [PERSON] A Quantum Key Distribution Routing Scheme for a Zero-Trust QKD Network System:  
A Moving Target Defense Approach. Big Data Cog  
mechanics, such as the no-cloning theorem, which prevents the undetected replication of quantum states [3]. Qubits, employed in QKD, are typically transmitted by photons across distances of up to 833 km using protocols like BB84 and BBM92 through optical fibers or free space [4,5]. Despite QKD's theoretical security, it encounters practical challenges, especially over long distances. Photon loss and decoherence limit its effective range. To address these limitations, technologies such as quantum repeaters, trusted relays, and satellite-based solutions have been developed [6,7]. Quantum repeaters improve communication distances by segmenting the channel into shorter links, facilitating entanglement swapping and purification [8]. Trusted relays, using one-time pad (OTP) encryption, extend QKD's reach by enhancing its scalability and flexibility [5,9,10]. Alternatively, satellite-based QKD circumvents terrestrial limitations by enabling global key distribution. However, these advancements come with their own set of vulnerabilities. For example, photon sources and detector imperfections can be exploited through side-channel and Trojan horse attacks [11], while satellite-based systems are particularly vulnerable to signal jamming and denial-of-service attacks [12]. Advanced quantum hacking techniques, such as photon number splitting (PNS) attacks, exploit multiphoton emissions to extract information without detection [13]. Moreover, the assumption that relays are secure poses risks in real-world applications, as classical components of QKD networks remain susceptible to data tampering and replay attacks [14]. Therefore, enhanced security measures are necessary to protect QKD networks.