SDN-Based Hybrid Quantum-Safe Domain Intercommunication within MadQCI

The importance of quantum-key-distribution (QKD) networks is growing rapidly, not only because the underlying QKD protocol is immune against any (known or unknown) attacks but also as these infrastructures can be operated in a hybrid mode, together with emerging quantum safe, or post quantum cryptography (PQC), public key protocols. Hybrid solutions appear to be the most promising remedy against realworld security risks, posed by prospective quantum computers. Simultaneously, telecommunication operators are embracing novel network paradigms, such as software-defined networking (SDN), due to distinct advantages over traditional approaches. SDN-inspired architectures can also be used for QKD and hybrid QKD-PQC networks. These architectures allow a seamless integration of QKD and hybrid QKD-PQC into production networks, significantly increasing the security of the latter. However, there has only been very limited research on optimal strategies for establishing hybrid connectivity across different organizational domains. The present contribution introduces two methods on interconnecting different technological and administrative domains for such networks. The proposed scheme is QKD-vendor independent and relies heavily on standard and open interfaces. It enables a complete end-to-end communication between applications running on nodes in different domains. It can be used for the secure interconnection of different SDN based telecommunication domains with additional QKD / hybrid protection and has been tested within the Madrid QuantumCommunication Infrastructure.