Constraints Visualization and Specification for Activity-centric Access Control

With the advancement of the technologies in networking, communication, automation engineering and artificial intelligence (AI), our society is evolving as a smart and connected community. Involving less human intervention, the devices in smart ecosystems often perform prolonged operations based on the system requirements, and environmental conditions. To control these long-lived operations (referred as activities) performed by devices, an Activity-Centric Access Control (ACAC) model was proposed. While the policies for static dependencies between activities have been recently specified, research is needed for dependencies in dynamically changing scenarios such as dynamic separation of activities. Further, these ACAC specifications lack the discussion about the properties of the activities such as usage count and duration, cardinality of sources and objects, and if there is any connection between the changing environmental conditions and these properties in terms of activity control. To effectively address these requirements, it is essential to analyze and specify the static and dynamic factors as constraints on activity execution to enhance the security and safety of the systems.In this paper, we define and specify the constraints for ACAC model. We present a conceptual class diagram template using Unified Modeling Language (UML) for ACAC components and their relations. Further, we specify the ACAC constraints using Object Constraint Language (OCL). For the visualization of the constraints and understanding of the OCL expressions, we show the violation patterns for each constraint using UML object diagram templates. The paper also identifies conflicts in a smart farming use case scenario which violates the constraints while satisfying the system security policies. The constraint violation patterns presented in this paper help in the identification of the conflicts in the policies. It shows the importance of the visualization of the constraint violation patterns that could occur in real time applications.