Paper 2006/048

New Results on Multipartite Access Structures

Javier Herranz and German Saez

Abstract

In a multipartite access structure, the set of players is divided into $K$ different entities, in such a way that all players of the same entity play the same role in the structure. Not many results are known about these structures, when $K \geq 3$. Even if the total characterization of ideal multipartite access structures seems a very ambitious goal, we take a first step in this direction. On the one hand, we detect some conditions that directly imply that a multipartite structure cannot be ideal. On the other hand, we prove that three wide families of multipartite access structures are ideal. We believe that the techniques employed in these proofs are so general that they could be used to prove in the future more general results related to the characterization of ideal multipartite access structures.