Chinese Remainder Theorem Based Hierarchical Access Control for Secure Group Communication

Secure group communication with hierarchical access control refers to a scenario where 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; but the converse is not allowed. In this paper, we propose a new scheme CRTHACS, which is based on the Chinese Remainder Theorem. The scheme not only enables secure hierarchical control but also provides the following properties: hiding of hierarchy and receivers, authentication of both senders and messages, and a mechanism for the receiver to directly derive the key of a message.