Optimization of Cryptographic Key Routing in Complex Multi-Domain QKD Networks

The QRO-Route project addresses a critical research problem in quantum communication — the efficient and secure routing of cryptographic keys within multi-domain Quantum Key Distribution (QKD) networks. Multi-domain QKD networks refer to the networks of different EU member states that will, in the future, need to communicate and exchange cryptographic keys with one another. These networks differ in their implementation approaches, the technologies used across the layers of the QKD architecture, the protocols employed, and other characteristics that affect the speed, security and efficiency of key exchange — and therefore the selection of the optimal route.

These networks form the backbone of the emerging EuroQCI initiative, which aims to establish a pan-European quantum communication infrastructure to secure sensitive data against threats posed by quantum computing. Despite the strategic importance of QKD systems, significant challenges remain in ensuring optimal resource usage, routing security, and interoperability across networks of varying architectures.

The main objective is to design and validate a dynamic routing algorithm that facilitates the secure and efficient exchange of quantum-generated cryptographic keys across heterogeneous QKD networks. The project begins by identifying the key parameters and architectural features that impact performance. These insights inform the design of an innovative routing algorithm, implemented in a purpose-built simulation environment that models realistic network topologies and scenarios for performance validation under controlled conditions.

Results are disseminated through high-impact scientific publications, presentations at international conferences, and the release of publicly available datasets. The work aligns with ongoing standardization efforts in the EuroQCI initiative, ensuring the results are practically applicable and in line with EU strategic priorities — supporting Croatia's role in the European quantum ecosystem.