Formal Definitions for Trust in Trusted Computing

Trust, the most fundamental concept in Trusted Computing, is a pervasive notion and, as such, has been studied thoroughly in a variety of different fields. Based on a survey of trust and security, two formal definitions for trust in Trusted Computing are presented in this paper: one for trust between coequal components (the direct trust) and the other for trust in specialization-employed environment (the recommended trust). Therefore, the rationality of the properties of trust relation has been comprehensively discussed in detail, such as reflexive, symmetric, and conditionally transitive. Finally, several prospective insights are proposed towards modeling a trusted system on basis of those definitions.