Quantum Key Distribution in "softwarised" infrastructures

Quantum computing is one of the main concerns of information security in recent years, due to its capability of breaking in polynomial time asymmetric algorithms, that are the foundation of the most used security protocols. Quantum Key Distribution (QKD) is a promising approach to mitigate the issue which leverages the quantum physics phenomena to introduce cryptographic information-theoretical secure key exchanges even in the presence of powerful quantum computers, but its adoption is still at the early stage and a lot of works focused on the physical aspects and devices instead of the implementation issues. Today's infrastructures are shifting to distributed scenarios where servers are hosted in data centers often shared among several customers and spread over different locations; cloud computing is becoming a fundamental block in the deployment of applications and hence cryptographic protocols of the future must be compatible with these architectures. This work proposes a complete software stack, the Quantum Key Server (QKS), to handle key exchanges and to serve keys to applications, independently from the quantum protocol or the physical device used, compliant with the ETSI standard to guarantee large interoperability. The server architecture embraces the microservices pattern to provide a cloud-native solution highly scalable, that can be easily integrated into an already deployed scenario and that can be easily extended in the future. Despite a previous version of this stack has been proposed by the TORSEC group, this new version solves its performance issues providing a server able to manage several clients at a time and to support communications over QKD networks where not all nodes pairs could be directly connected by quantum channels, bringing classical routing techniques into QKD. The stack can be deployed into Kubernetes, which is the most used orchestrator for the management of containerized applications, and this work proposes an operator to simplify the initialization procedure and the key retrieving process.