Secure agreement protocols

Reliable and atomic group multicast have been proposed as fundamental communication paradigms to support secure distributed computing in systems in which processes may behave maliciously. These protocols enable 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 multicast, deliver these messages in the same order. We present new reliable and atomic group multicast protocols for asynchronous distributed systems. We also describe their implementation as part of Rampart, a toolkit for building high-integrity distributed services, i.e., services that remain correct and available despite the corruption of some component servers by an attacker. To our knowledge, Rampart is the first system to demonstrate reliable and atomic group multicast in asynchronous systems subject to process corruptions.