Byzantine consensus with unknown participants

Abstract

Consensus is a fundamental building block used to solve many practical problems that appear on reliable distributed systems. In spite of the fact that consensus is being widely studied in the context of classical networks, few studies have been conducted in order to solve it in the context of dynamic and self-organizing systems characterized by unknown networks. While in a classical network the set of participants is static and known, in a scenario of unknown networks, the set and number of participants are previously unknown. This work goes one step further and studies the problem of Byzantine Fault-Tolerant Consensus with Unknown Participants, namely BFT-CUP. This new problem aims at solving consensus in unknown networks with the additional requirement that participants in the system can behave maliciously. This paper presents a solution for BFT-CUP that does not require digital signatures. The algorithms are shown to be optimal in terms of synchrony and knowledge connectivity among participants in the system. © 2008 Springer Berlin Heidelberg.