User-Oriented Batch Processing of Individual Rekeying

For a long time multicast security researches have been going on. In multicast security the group key must be changed whenever users join or leave. We called it ´rekeying´. There are so far two main schemes of rekeying. One is individual rekeying and the other is periodic rekeying. However the two schemes have so serious weakness in some environment that they might not be suitable for scalable and efficient multicast security service. So this paper describes what the problems are in the legacy both schemes and in actual world, and suggests the solution, the user-oriented batch processing of individual rekeying, for security and efficiency.