Trustworthiness management in the IoT: The importance of the feedback

The Internet of Things (IoT) is creating a world where physical objects are seamlessly integrated to provide advanced and intelligent services for human beings in their day-to-day life style. The realization of complex applications comes from the collaboration of groups of objects; in such a network, objects seek other devices that can provide the services they need for the implementation of the applications they are taking part to. Before exploiting the found services, it is important to evaluate to which extent the potential service providers are trustable. In the resulting trustworthiness management model, an important role is taken by the feedback generated by the consumers of the service. In this paper, we focus on the challenge of generating consistent feedback for the trust evaluation in the exchange of services in IoT. We start by discussing how the concept of feedback has been exploited so far in trust management systems; then, we analyze the different aspects of the feedback so that it results to be a multi-dimensional concept.