Toward Modeling Trust Cyber-Physical Systems: A Model-based System Engineering Method

Abstract

Developing trust in cyber-physical systems (CPSs) is a challenging task. Trust in CPS is needed for carrying out their intended duties and is reasonably safe from misuse and intrusion; it also enforces the applicable security policy. As an example, medical smart devices, many researches have found that trust is a key factor in explaining the relationship between individual beliefs about technological attributes and their acceptance behavior; and have associated medical device failures with severe patient injuries and deaths. The cyber-physical system is considered a trust system if the principles of security and safety, confidentiality, integrity, availability, and other attributes are assured. However, a lack of sufficient analysis of such systems, as well as appropriate explanation of relevant trust assumptions, may result in systems that fail to completely realize their functionality. The existing research does not provide suitable guidance for a systematic procedure or modeling language to support such trust-based analysis. The most pressing difficulties are achieving trust by design in CPS and systematically incorporating trust engineering into system development from the start of the system life cycle. Still, there is a need for a strategy or standard model to aid in the creation of a safe, secure, and trustworthy CPS. Model-based system engineering (MBSE) approaches for trust cyber-physical systems are a means to address system trustworthiness design challenges. This work proposes a practical and efficient MBSE method for constructing trust CPS, which provides guidance for the process of trustworthiness analysis. The SysML-based profile is supplied, together with recommendations on which approach is required at each process phase. The MBSE method is proven by expanding the autonomous car SysML and UML diagrams, and we show how trust considerations are integrated into the system development life cycle.