  Key management in multicast dynamic groups, where users can leave or join at
their ease is one of the most crucial and essential part of secure
communication. Various efficient management strategies have been proposed
during last decade that aim to decrease encryption costs and transmission
overheads. In this report, two different types of key management schemes are
proposed. First proposed scheme is based on One-way function tree (OFT). The
proposed scheme fulfills the security gaps that have been pointed out in recent
years. Second proposed scheme is based on logical key hierarchy (LKH). This
proposed scheme provides better performance for, rather inflexible and
expensive, LKH scheme.
