Exploiting usage control for implementation and enforcement of security by contract

The widespread adoption of IoT-based smart home technologies has transformed how people interact with their living spaces, offering greater control over everyday tasks. However, this increased connectivity introduces significant security challenges, particularly in managing applications that can control devices within the smart home. Users need effective ways to define and enforce security policies that permit or deny specific behaviors of these applications. Such policies should allow users to control what actions applications can perform, ensuring that they comply with security and privacy preferences. This paper proposes a hybrid framework that combines Security by Contract (S$\times$C) and Usage Control (UCON) to address these challenges and provide a comprehensive security solution with low impact on system performance. S$\times$C ensures verification of the application behavior, described formally as a contract, against predefined XACML-based policies. UCON enables continuous monitoring and enforcement of security policies during application execution. The theoretical foundations of the methodology combining these frameworks are based on labeled state/transition systems and their model-checking-based verification. Through experimental validation on a real testbed, we explore the feasibility of the proposed approach by evaluating its performance across various test campaigns, offering insights into its ability to manage policy enforcement and revocation processes with low overhead.