Reliable and atomic group multicast have been pro-posed as fundamental communication paradigms to sup-port secure distributed computing in systems in which processes may behave maliciously. These protocols en-able messages to be multicast to a group of processes, while ensuring that all honest group members deliver the same messages and, in the case of atomic multi-cast, deliver these messages in the same order. We present new reliable and atomic group multicast pro-tocols for asynchronous distributed systems. We also describe their implementation as part of Rampart, a toolkit for building high-integrily distributed services, i.e., services that remain correct and available despite the corruption of some component servers by an at-tacker. To our knowledge, Rampart is the first system to demonstrate reliable and atomic group multicast in asynchronous systems subject to process corruptions. 1