TY - GEN
T1 - On the complexity of fault-tolerant consensus
AU - Kowalski, Dariusz R.
AU - Mirek, Jarosław
N1 - Funding Information:
Supported by the Polish National Science Center (NCN) grant UMO-2017/25/B/ST6/02553.
Publisher Copyright:
© Springer Nature Switzerland AG 2019.
PY - 2019
Y1 - 2019
N2 - We consider the problem of reaching agreement in a distributed message-passing system prone to crash failures. Crashes are generated by Constrained adversaries - a Weakly-Adaptive adversary, who has to fix, in advance, the set of f crash-prone processes, and a k-Chain-Ordered adversary, who orders all the processes into k disjoint chains and has to follow this order when crashing them. Apart from these constraints, both of them may crash processes in an adaptive way at any time. While commonly used Strongly-Adaptive adversaries model attacks and Non-Adaptive ones - pre-defined faults, Constrained adversaries model more realistic scenarios when there are fault-prone dependent processes, e.g., in hierarchical or dependable software/hardware systems. In this view, our approach helps to understand better the crash-tolerant consensus in more realistic executions. We propose time-efficient consensus algorithms against such adversaries. We complement our algorithmic results with (almost) tight lower bounds, and extend the one for Weakly-Adaptive adversaries to hold also for (syntactically) weaker Non-Adaptive adversaries. Together with the consensus algorithm against Weakly-Adaptive adversaries (which automatically translates to the Non-Adaptive adversaries), these results extend the state-of-the-art of the popular class of Non-Adaptive adversaries, in particular, the result of Chor, Meritt and Shmoys [7], and prove separation gap between Constrained adversaries (including Non-Adaptive ones) and Strongly-Adaptive adversaries, analyzed by Bar-Joseph and Ben-Or [3] and others.
AB - We consider the problem of reaching agreement in a distributed message-passing system prone to crash failures. Crashes are generated by Constrained adversaries - a Weakly-Adaptive adversary, who has to fix, in advance, the set of f crash-prone processes, and a k-Chain-Ordered adversary, who orders all the processes into k disjoint chains and has to follow this order when crashing them. Apart from these constraints, both of them may crash processes in an adaptive way at any time. While commonly used Strongly-Adaptive adversaries model attacks and Non-Adaptive ones - pre-defined faults, Constrained adversaries model more realistic scenarios when there are fault-prone dependent processes, e.g., in hierarchical or dependable software/hardware systems. In this view, our approach helps to understand better the crash-tolerant consensus in more realistic executions. We propose time-efficient consensus algorithms against such adversaries. We complement our algorithmic results with (almost) tight lower bounds, and extend the one for Weakly-Adaptive adversaries to hold also for (syntactically) weaker Non-Adaptive adversaries. Together with the consensus algorithm against Weakly-Adaptive adversaries (which automatically translates to the Non-Adaptive adversaries), these results extend the state-of-the-art of the popular class of Non-Adaptive adversaries, in particular, the result of Chor, Meritt and Shmoys [7], and prove separation gap between Constrained adversaries (including Non-Adaptive ones) and Strongly-Adaptive adversaries, analyzed by Bar-Joseph and Ben-Or [3] and others.
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U2 - 10.1007/978-3-030-31277-0_2
DO - 10.1007/978-3-030-31277-0_2
M3 - Conference contribution
AN - SCOPUS:85075608827
SN - 9783030312763
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 19
EP - 31
BT - Networked Systems - 7th International Conference, NETYS 2019, Revised Selected Papers
A2 - Atig, Mohamed Faouzi
A2 - Schwarzmann, Alexander A.
PB - Springer
T2 - 7th International Conference on Networked Systems, NETYS 2019
Y2 - 19 June 2019 through 21 June 2019
ER -