FORMALIZING TRUST REQUIREMENTS AND SPECIFICATION IN SERVICE WORKFLOW ENVIRONMENTS

The emergence of advance communication technologies such as Internet has changed the nature of face-to-face towards virtual interactions in the form of services. Proliferation of services has enabled the creation of new value-added services composed of several sub-services in a pre-specified manner, known as service workflows. There are a number of security issues as workflows require disparate services to dynamically collaborate and interact on demand. Trust is an enabling technology serving as an adaptive and platform independent solution that fits in this context. However, the lack of consensus on a unified trust definition and the traditional mindset of treating trust requirements separately pose the difficulty in developing formal specification. This paper provides a formal framework to this problem. The central part of the paper is logic based formalism with algebraic expressions to formally specify trust requirements. A trust definition and three modes of trust are described with algebraic operators to form specification formulae. The contribution of the framework is to allow trust requirements to be formally and uniformly specified by each distributed autonomous service, serving as a core component for automatic compliance checking in service workflows.