Bounds for key distribution patterns

Abstract

This paper is concerned with the problem of distributing pieces of information to nodes in a network in such a way that any pair of nodes can compute a secure common key but the amount of information stored at each node is small. It has been proposed that a special type of finite incidence structure, called a key distribution pattern (KDP), might provide a good solution to this problem. We give various lower bounds on the information storage of KDPs. Our main result shows that in general KDP schemes necessarily have greater information storage at the nodes than the minimum possible. This minimum is achieved by a scheme not based on KDPs. © 1999 International Association for Cryplologic Research.