Secure Access Control Scheme Of Cyber-Physical System

Cyber-Physical Systems (CPS) are integrations of computation with physical processes. Embedded computers and networks monitor and control the physical processes, usually with feedback loops where physical processes affect computations. Cyber-Physical System can be considered as embedded system with wireless or wired networks. It contains three parts of components as sensor, computing control unit and actuator which interactive with each other by the network.On top of the information processing, CPS additionally bring in the concept of physical entity. New challenges as security operation, cooperation between entities, reliability and access control need to be solved. CPS is a fresh research filed resulting many problems should be resolved before deployment.According to the security requirement of the CPS, in this paper, an access control model, namely FEAACS, which is presented for Cyber-Physical Systems, which can not only provide the ability to control access to data in normal situations, but also adaptively assign emergency-role and permissions to specific subjects and inform subjects without explicit access requests to handle emergency situations in a proactive manner. In FEAACS, emergency-group and emergency-dependency are introduced, emergencies are processed in sequence within the group and parallel processed among groups, a priority and dependency model called PD-Action Generation Model is used to select optimal response-action execution path aiming to eliminate all emergencies occurred within the system. Fault-tolerant access control polices are used after the failure of emergency management, alternate permissions and services to the substitute entitiesThe validity of FEAACS is verified by semi-formalized semantics as responsiveness, correctness, security, liveness and non-repudiation. At the end of the paper, a case study of hospital medical care applications is used to illuminate the access control model.