Sliding-window self-healing key distribution

We propose a new method for distributing a common key to a dynamic group over an unreliable channel. In [15], an unconditionally secure "self-healing" protocol that solves this problem and has significant advantages over previous work in this area is presented. However, the protocol suffers from inconsistent robustness, high overhead and expensive maintenance costs. We propose a more practical self-healing protocol that attempts to address these three problems. First, we use a sliding window to make error recovery consistently robust. Second, we significantly reduce overhead. Finally, we give the group manager the ability to spread the cost of personal key distribution over multiple sessions, rather than having to distribute new personal keys to all users at the same time.