Information-theoretically secure entity authentication in the multi-user setting

Abstract

In this paper, we study unilateral entity authentication protocols and mutual entity authentication protocols with informationtheoretic security in the multi-user setting. To the best of our knowledge, only one paper by Kurosawa studied an entity authentication protocol with information-theoretic security, and an unilateral entity authentication protocol in the two-user setting was considered in his paper. In this paper, we extend the two-user unilateral entity authentication protocol to the multi-user one. In addition, we formally study an informationtheoretically secure mutual entity authentication protocol in the multiuser setting for the first time. Specifically, we formalize a model and security definition, and derive tight lower bounds on size of users’ secretkeys, and we show an optimal direct construction.