Unmanned Autonomous Systems (UAS) are used nowadays in a wide range of applications ranging from civil to military sector. These systems are characterized by a highly dynamic operation with fast response to critical environments which raises different challenges to ensure safety and security against cyber threats. For instance, Root-of-Trust (RoT) is a set of functions, reliable for the UAS, which becomes the starting point for secure operations. These secure operations normally require high computation resources to respect the real-time constraints of UAS applications. Different pure software implementation has been proposed to reduce the response time required for security operations. However, they may lead to overuse of computational capabilities that could reduce the real-time response performance of UAS during critical operations.