Reliable Channels for Systems in the Presence of Byzantine Faults

Department of Computer Engineering, Kuwait University, P.O. Box 5969, Safat 13060 Kuwait

Abstract

Consider a distributed system that delivers each message from a process to its destination if the message transmission does not experience any faults and only delivers those sent by a non-faulty system process. Such a system is referred to as a reliable message passing system. A reliable message passing system requires a reliable channel, a communication channel between a pair of processes that always detects a fault in message transmission and each detected fault is an actual fault, to be implemented. In this paper, we first identify the necessary conditions to detect some restricted form of Byzantine Faults in a message passing system where n disjoint paths exist between each pair of endpoints. We consider Byzantine Faults (BF) whose effect is limited to the modification of a message metadata, omission faults, and message replay. We then present a protocol implementing a reliable channel in message passing systems in the presence of n — 1 Byzantine Faults using n disjoint paths between each pair of communication endpoints where the paths with faults are not known apriori. The proposed protocol detects Byzantine Faults, where each detected fault, an actual fault, authenticates message origins, identifies faulty paths and classifies faults in the presence of multiple messages sent by various system processes.