General anonymous key broadcasting via Lagrangian interpolation

The authors presents a key management scheme for broadcast networks, which is a combination of broadcast encryption protocols of different kinds: an exclusion scheme based on Lagrangian interpolation in the exponent and a non-exclusion scheme. The authors show how to combine these techniques into one scheme in such a way that information on who is excluded and when they are excluded is hidden under certain adversary models, and communication overhead is independent of the system dynamics. Thus, the scheme is well suited for the general cases where the maximum number of excluded users is unpredictable.