Efficient Group Key Management Schemes for Multicast Dynamic   Communication Systems
  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. 
Muhammad Yasir Malik
cs.CR cs.NI