Towards secure and communication-efficient broadcast encryption systems

Many emerging network applications are based upon a group communication model where security is a critical design issue. We address the broadcast encryption problem of distributing to a group of network entities a confidential cryptographic key, which needs to be updated from session to session. The design goals of such a system essentially include not only security but also communication efficiency concerning the distribution of the session key. We show that there is a disconnect between the essence of broadcast encryption and a scheme proposed very recently. The observation also motivates us to seek for secure and efficient broadcast encryption solutions. Three distinctive constructions, based on the bilinear map, the one-way hash function, and the RSA cryptosystem, respectively, are then presented to demonstrate reasonable tweaks and various tradeoffs when designing practical group-oriented communication systems. These constructions exhibit not only promising security but also impressive communication efficiency, and we also discuss the diverse networking scenarios to which they are applicable.