Secure and Efficient Multicast Content Distribution

This paper proposes a multicast content distribution method over quantum key distribution (QKD) networks that improves delivery latency and resilience to link bandwidth limitations through mesh network design, while also contributing to reduced key consumption. Although QKD ensures information-theoretic security, its limited key generation rate poses challenges for scalable content delivery. To address this, we introduce a mechanism using random linear network coding in mesh topologies, where nodes adaptively collect and forward packets based on network conditions such as bandwidth and link quality. We evaluate the proposed method through numerical simulations on a mid-sized urban-regional network with 51 nodes. The results show that, even on redundant mesh topologies, our method suppresses key consumption by 16% and reduces delivery latency under constrained bandwidth scenarios by 51%, compared to conventional IP multicast over single-tree topologies.