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arXiv · 2002.03437

Network-Agnostic State Machine Replication

Erica Blum·Jonathan Katz·Julian Loss
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Abstract

We study the problem of state machine replication (SMR)---the underlying problem addressed by blockchain protocols---in the presence of a malicious adversary who can corrupt some fraction of the parties running the protocol. Existing protocols for this task assume either a synchronous network (where all messages are delivered within some known time $Δ$) or an asynchronous network (where messages can be delayed arbitrarily). Although protocols for the latter case give seemingly stronger guarantees, this is not the case since they (inherently) tolerate a lower fraction of corrupted parties. We design an SMR protocol that is network-agnostic in the following sense: if it is run in a synchronous network, it tolerates $t_s$ corrupted parties; if the network happens to be asynchronous it is resilient to $t_a \leq t_s$ faults. Our protocol achieves optimal tradeoffs between $t_s$ and $t_a$.

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Erica Blum, Jonathan Katz, Julian Loss. 2020-03-27. Network-Agnostic State Machine Replication. https://arxiv.org/abs/2002.03437

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