Modeling trust relationships for developing trustworthy Information systems

Developing a trustworthy information system is a challenging task. The overall trustworthiness of an information system depends on trust relationships that are generally assumed without adequate justification. However, lack of appropriate analysis of such relationships and of appropriate justification of relevant trust assumptions might lead to systems that fail to fully achieve their functionalities. Existing literature does not provide adequate guidelines for a systematic process or an appropriate modeling language to support such trust-focused analysis. This paper fills this gap by introducing a process that allows developers to capture possible trust relationships and to reason about them. The process is supported by a modeling language based on a set of concepts relating to trust and control and a CASE tool. An illustrative example from the UK health care domain is used to demonstrate the applicability and usefulness of the approach.