Level-based key establishment for multicast communication in mobile ad hoc networks

Many emerging mobile wireless applications use symmetric keys for secure multicast communication. This key has to be changed every time a user decides to leave or join the network. We introduce a novel hierarchical security framework for mobile ad hoc multicast networks in which data encryption is done using a symmetric key and key establishment using symmetric ´level´ keys and asymmetric node keys. Our primary contention is that the tree formation process should be integrated with the key exchange process and should not be treated as an add-on. Our scheme effectively handles the impact of mobility on key establishment while minimizing the number of messages to be exchanged.