2 Search Results for "Sheff, Isaac"

Document
DOI: 10.4230/LIPIcs.OPODIS.2025.8
Weaker Assumptions for Asymmetric Trust

Authors: Ignacio Amores-Sesar, Christian Cachin, Simon Holmgaard Kamp, and Juan Villacis

Published in: LIPIcs, Volume 361, 29th International Conference on Principles of Distributed Systems (OPODIS 2025)

Abstract
In distributed systems with asymmetric trust, each participant is free to make its own trust assumptions about others, captured by an asymmetric quorum system. This contrasts with ordinary, symmetric quorum systems and threshold models, where trust assumptions are uniformly shared among participants. Fundamental problems like reliable broadcast and consensus are unsolvable in the asymmetric model if quorum systems satisfy only the classical properties of consistency and availability. Existing approaches overcome this by introducing stronger assumptions. We show that some of these assumptions are overly restrictive, so much so that they effectively eliminate the benefits of asymmetric trust. To address this, we propose a new approach to characterize asymmetric problems and, building upon it, present algorithms for reliable broadcast and consensus that require weaker assumptions than previous solutions. Our methods are general and can be extended to other core problems in systems with asymmetric trust.
Cite as

Ignacio Amores-Sesar, Christian Cachin, Simon Holmgaard Kamp, and Juan Villacis. Weaker Assumptions for Asymmetric Trust. In 29th International Conference on Principles of Distributed Systems (OPODIS 2025). Leibniz International Proceedings in Informatics (LIPIcs), Volume 361, pp. 8:1-8:18, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2025)

Copy BibTex To Clipboard

@InProceedings{amoressesar_et_al:LIPIcs.OPODIS.2025.8,
  author =	{Amores-Sesar, Ignacio and Cachin, Christian and Kamp, Simon Holmgaard and Villacis, Juan},
  title =	{{Weaker Assumptions for Asymmetric Trust}},
  booktitle =	{29th International Conference on Principles of Distributed Systems (OPODIS 2025)},
  pages =	{8:1--8:18},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-409-3},
  ISSN =	{1868-8969},
  year =	{2026},
  volume =	{361},
  editor =	{Arusoaie, Andrei and Onica, Emanuel and Spear, Michael and Tucci-Piergiovanni, Sara},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.OPODIS.2025.8},
  URN =		{urn:nbn:de:0030-drops-251812},
  doi =		{10.4230/LIPIcs.OPODIS.2025.8},
  annote =	{Keywords: Asymmetric Trust, Quorum Systems, Reliable Broadcast, Consensus}
}
Document
DOI: 10.4230/LIPIcs.OPODIS.2020.5
Heterogeneous Paxos

Authors: Isaac Sheff, Xinwen Wang, Robbert van Renesse, and Andrew C. Myers

Published in: LIPIcs, Volume 184, 24th International Conference on Principles of Distributed Systems (OPODIS 2020)

Abstract
In distributed systems, a group of learners achieve consensus when, by observing the output of some acceptors, they all arrive at the same value. Consensus is crucial for ordering transactions in failure-tolerant systems. Traditional consensus algorithms are homogeneous in three ways: - all learners are treated equally, - all acceptors are treated equally, and - all failures are treated equally. These assumptions, however, are unsuitable for cross-domain applications, including blockchains, where not all acceptors are equally trustworthy, and not all learners have the same assumptions and priorities. We present the first consensus algorithm to be heterogeneous in all three respects. Learners set their own mixed failure tolerances over differently trusted sets of acceptors. We express these assumptions in a novel Learner Graph, and demonstrate sufficient conditions for consensus. We present Heterogeneous Paxos, an extension of Byzantine Paxos. Heterogeneous Paxos achieves consensus for any viable Learner Graph in best-case three message sends, which is optimal. We present a proof-of-concept implementation and demonstrate how tailoring for heterogeneous scenarios can save resources and reduce latency.
Cite as

Isaac Sheff, Xinwen Wang, Robbert van Renesse, and Andrew C. Myers. Heterogeneous Paxos. In 24th International Conference on Principles of Distributed Systems (OPODIS 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 184, pp. 5:1-5:17, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)

Copy BibTex To Clipboard

@InProceedings{sheff_et_al:LIPIcs.OPODIS.2020.5,
  author =	{Sheff, Isaac and Wang, Xinwen and van Renesse, Robbert and Myers, Andrew C.},
  title =	{{Heterogeneous Paxos}},
  booktitle =	{24th International Conference on Principles of Distributed Systems (OPODIS 2020)},
  pages =	{5:1--5:17},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-176-4},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{184},
  editor =	{Bramas, Quentin and Oshman, Rotem and Romano, Paolo},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.OPODIS.2020.5},
  URN =		{urn:nbn:de:0030-drops-134909},
  doi =		{10.4230/LIPIcs.OPODIS.2020.5},
  annote =	{Keywords: Consensus, Trust, Heterogeneous Trust}
}
  • Refine by Type
  • 2 Document/PDF
  • 1 Document/HTML

  • Refine by Publication Year
  • 1 2026
  • 1 2021

  • Refine by Author
  • 1 Amores-Sesar, Ignacio
  • 1 Cachin, Christian
  • 1 Kamp, Simon Holmgaard
  • 1 Myers, Andrew C.
  • 1 Sheff, Isaac
  • Show More...

  • Refine by Series/Journal
  • 2 LIPIcs

  • Refine by Classification
  • 2 Theory of computation → Distributed algorithms
  • 1 Computer systems organization → Availability
  • 1 Computer systems organization → Peer-to-peer architectures
  • 1 Computer systems organization → Redundancy
  • 1 Computer systems organization → Reliability
  • Show More...

  • Refine by Keyword
  • 2 Consensus
  • 1 Asymmetric Trust
  • 1 Heterogeneous Trust
  • 1 Quorum Systems
  • 1 Reliable Broadcast
  • Show More...

Any Issues?
X

Feedback on the Current Page

CAPTCHA

Thanks for your feedback!

Feedback submitted to Dagstuhl Publishing

Could not send message

Please try again later or send an E-mail
© 2023-2026 Schloss Dagstuhl – LZI GmbH Schloss Dagstuhl – LZI GmbH About DROPS Imprint Privacy Contact