Trust and Privacy: Informal Ways to Assess Risk on Opportunistic Exchanges

With the astounding number of mobile devices and the increase of wireless capabilities, including the possibilities of direct interactions between them, without the use of a provider, the overall scenario becomes increasingly attractive. Whether on the way to work or out shopping, opportunistic encounters and exchanges of information can take place and render windows of opportunity, given one has the right tools. This work deals with the problem of assessing the risks that users take to interact with each other without a reliable source of information that could assign them a trust level. Informal signs such as periodicity of eventual early encounters are used to assess trust. The trust management system uses an ontology to normalize terms and facilitate the conversation between newly encountered concepts, possibly from other ontologies. A case is implemented to show the system’s possibilities.