Secure Group Communications with Hierarchical Access Control

Abstract

Secure group communication (SGC) with hierarchical access control (HAC) refers to a scenario in which a group of members is divided into a number of subgroups located at different privilege levels and a high-level subgroup can receive and decrypt messages within any of its descendant lower-level subgroups, while the reverse is not allowed. HAC is generally enforced using cryptography based techniques [Birget et al., 2001] ie, cryptographic keys play a primary role in the control of access rights. If the members of a higher level subgroup possess or can derive the key of a lower level subgroup, they have the right to access all messages within the lower level subgroup. In this chapter, we discuss several typical SGC schemes with HAC.