This paper presents a new protocol for atomic broadcast in an asynchronous network with a maximal number of Byzantine failures. It guarantees both safety and liveness without making any timing assumptions or using any type of ``failure detector,'' and its amortized message and computational complexity is essentially the same as that of a simple ``Bracha broadcast.''
Under normal circumstances, the protocol runs in an ``optimistic mode,'' with extremely low message and computational complexity --- essentially, just performing a Bracha broadcast for each request. In particular, no ``expensive'' public-key cryptographic operations are used. In rare circumstances, the protocol may briefly switch to a ``pessimistic mode,'' where both the message and computational complexity are significantly higher than in the ``optimistic mode,'' but are still reasonable.
Keywords: Asynchronous Consensus, Byzantine Faults, Atomic Broadcast, State Machine Replication
By: Klaus Kursawe and Victor Shoup
Published in: RZ3344 in 2001
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