Obligations in Trust Negotiation

Trust negotiation frameworks allow communicating parties to incrementally establish trust in one another to achieve security goals. The goals we focus on deal with sharing sensitive information that is protected by a disclosure policy. Traditionally, such policies are satisfied through the use of signed credentials that express role memberships or attributes. The requirements in these policies are known as provisions, and represent past and present state. Although useful, provisions can sometimes prove too rigid, are susceptible to schema-matching problems, and cannot provide assurances on how information is used once it has been shared. In this paper, we propose a means of augmenting trust negotiation frameworks to support obligations, which are commitment-based requirements to perform certain actions in the future. We provide a metamodel for such a framework along with a method of converting provisions into sets of obligations. We analyze the complexity of this conversion, and then provide a study of obligation optimality during the negotiation.