The Functional Dependence Relation on Hypergraphs of Secrets

The paper considers interdependencies between secrets in a multiparty system. Each secret is assumed to be known only to a certain fixed set of parties. These sets can be viewed as edges of a hypergraph whose vertices are the parties of the system. In previous work, the authors investigated properties of interdependencies that are expressible through a multi-argument relation called independence, which is a generalization of a binary relation also known as nondeducibility. This work studies properties expressible through functional dependence. The main result is a complete and decidable logical system that describes interdependencies on a fixed hypergraph.