This work examines the interplay of inter-personal and inter-organizational trust, two distinct but related concepts, through a theoretic inter-organizational trust-based security model for a multi-agent system information-sharing community. A calculus that mathematically models trust building at the inter-organizational level is at the heart of this model. In interorganizational or inter-firm exchange, the role of the boundary spanner, an organizational representative, is important in reducing asymmetries that may exist between the two parties. Trust is a crucial component to the dyadic interaction at the inter-personal or boundary spanner level, and the trust established at this level affects, as well, the overall quality of the relationship at the inter-organizational level. Trust, as an aspect of social control, is thus viewed a more effective mechanism for security in an open, distributed system, like an information-sharing community. The inter-organizational trust-based security...