Network-wide Quantum Key Distribution with Onion Routing Relay

Abstract: The advancement of quantum computing threatens classical cryptographic methods, necessitating the development of secure quantum key distribution (QKD) solutions for QKD Networks (QKDN). In this paper, a novel key distribution protocol, Onion Routing Relay (ORR), that integrates onion routing (OR) with post-quantum cryptography (PQC) in a key-relay (KR) model is evaluated for QKDNs. This approach increases the security by enhancing confidentiality, integrity, authenticity, and anonymity in quantum-secure communications. By employing PQC-based encapsulation, ORR pretends to avoid the security risks posed by intermediate malicious nodes and ensures end-to-end security. Results show that the performance of the ORR model, against current key-relay (KR) and trusted-node (TN) approaches, demonstrating its feasibility and applicability in high-security environments maintaining a consistent Quality of Service (QoS). The results show that while ORR incurs higher encryption overhead, it provides substantial security improvements without significantly impacting the overall key distribution time.