Multicast communication is the main mode of communication for a wide range of Internet services such as video broadcasting and multi-party teleconferencing where there are multiple recipients. A secure multicast system allows a group initiator (or a centre) to send message over a multicast channel to a dynamically changing group of users. The main challenge in secure multicasting is efficient group key management. We propose new schemes for user revocation that can be used to establish a common key among subgroups of users. The schemes can be used with static or dynamic group initiator and allow temporary and permanent revocation of users. We also give a method of adding authentication to the proposed schemes. We prove security and compare efficiency of the new schemes.