Bounds and constructions for unconditionally secure distributed key distribution schemes for general access structures

Abstract

In this paper we investigate the issues concerning the use of a single server across a network, the key distribution center (KDC) to enable private communications within groups of users. After providing several motivations, showing the advantages related to the distribution of the task accomplished by this server, we describe a model for such a distribution, and present bounds on the amount of resources required in a real-world implementation: random bits, memory storage, and messages to be exchanged. Moreover, we introduce a linear algebraic approach to design optimal schemes distributing a KDC, and we point out that some previous constructions belong to the proposed framework.