Secure group communications and hierarchical access control

‘Secure group communications’ (SGC) refers to a scenario in which a group of participants can receive and send messages to group members, in a way that outsiders are unable to glean any information even when they are able to intercept the messages. Secure group communications rely on the protocols and the fast developing theoretical tools of modern cryptology. With the exponential growth in modern communications, SGC is becoming an extremely important research area because of the need to provide privacy and authenticity in communications. Many applications that require SGC are now widely practiced, such as teleconferencing, tele-medicine, real-time information services, distributed interactive simulations, collaborative work and the deployment of VPN (Virtual Private Network). We investigate burst behavior in secure group communications and propose two efficient schemes to deal with burst operations. Hierarchical access control is a general and important problem in distributed computing environments and a particular problem in secure group communications. There is a gap between real applications of access control and the existing solutions for access control, i.e., in real applications there are two hierarchies: user hierarchy and resource hierarchy. On the other hand, existing solutions assume that there is a single hierarchy. We formalize the access control problem and bridge this gap by proposing a unifying algorithm to combine two hierarchies into a single hierarchy. In general, the dynamical distributed access control problem is very difficult and does not have easy solutions. We provide solutions by limiting the problem\u27s domain and propose two simple, yet efficient dynamic hierarchical access control schemes: (i) an Index based hierarchical access control scheme for tree structures, and (ii) a Chinese Remainder Theorem based hierarchical access scheme for secure group communications