Reviewing trust from societal to digital to build unified trust model

Trust plays an important role in every individual’s life and on daily basis. Trust models aim to capture the computation, transmission and perception of types of trust in a computational setting. The concept of trust varies from person to person without any unified definition; however, the most common types of trust are reliability trust, defined as subjective probability by which an entity expects that another entity perform a given action; and decision trust, defined as one entity is depending on another entity in a given condition with a feeling of relative security, even with the possibility of negative consequences. This paper reviews trust from a societal perspective and, then, gives an overview of digital trust in some domains of computer science and shows how it is related to cyber security and privacy. This review paper shows that unified trust model is one of the most important human requirements in the digital globalization era and reviewing digital trust is key to unify trust in models.