We propose a complete architecture for a QKD (Quantum Key Distribution) network, from the physical layer up to the network controller. Our design is based on a centralized approach for Quantum Keys Management to mitigate security risks on the trusted relays. This paper explores the essential components, design principles, and architectural models of QKD networks, which are critical in enabling secure information ex-change amid rising cybersecurity concerns. Security within QKD networks is paramount, encompassing measures to address various threats. This includes the establishment of quantum-safe classical networks, rigorous node authentication, and dynamic eavesdropping countermeasures. Moreover, our architecture accommodates scalability and interoperability to integrate new nodes and technologies seamlessly. All these features are addressed in this paper, with a focus on the centralized Key Management System (KMS) we designed to drive QKD.