Abstract:
A Key Distribution Center of a network is a server who generates and distributes secret keys to groups of users for secure communication. A Distributed Key Distribution Center is a set of servers that jointly realizes a Key Distribution Center. In this paper we describe in terms of information theory a model for distributed key distribution centers, and we present lower bounds holding in the model for the main resources needed to set up and manage a distributed center, i.e., memory storage, randomness, and bandwidth. Then, we show that a previously proposed protocol which uses a bidimensional extension of Shamir's secret sharing scheme meets the bounds and it is, hence, optimal.