Abstract:
Self-healing key distribution schemes allow group managers to broadcas session keys to large and dynamic groups of users over unreliable chan Roughly speaking, even if during a certain session some broadcast messages are lost due to network faults, the self-healing property of the scheme enables each group member to recover the key from the broadcast messages he/she has received before and after that session. Such schemes are quite suitable in supporting secure communication in wireless networks and mobile wireless ad-hoc networks. Recent papers have focused on self-healing key distribution, and have provided definitions, stated in terms of the entropy function, and some constructions. The contribution of this paper is the following:
- We analyse current definitions of self-healing key distribution and, for two of them, we show that no protocol can achieve the definition.
- We show that a lower bound on the size of the broadcast message, previously derived, does not hold.
- We propose a new definition of self-healing key distribution, and we show that it can be achieved by concrete schemes.
- We give some lower bounds on the resources required for implementing such schemes i.e., user memory storage and communication complexity. We prove that the bounds are tight.