4 Search Results for "Freitas, Luciano"


Document
Distributed Randomness from Approximate Agreement

Authors: Luciano Freitas, Petr Kuznetsov, and Andrei Tonkikh

Published in: LIPIcs, Volume 246, 36th International Symposium on Distributed Computing (DISC 2022)


Abstract
Randomisation is a critical tool in designing distributed systems. The common coin primitive, enabling the system members to agree on an unpredictable random number, has proven to be particularly useful. We observe, however, that it is impossible to implement a truly random common coin protocol in a fault-prone asynchronous system. To circumvent this impossibility, we introduce two relaxations of the perfect common coin: (1) approximate common coin generating random numbers that are close to each other; and (2) Monte Carlo common coin generating a common random number with an arbitrarily small, but non-zero, probability of failure. Building atop the approximate agreement primitive, we obtain efficient asynchronous implementations of the two abstractions, tolerating up to one third of Byzantine processes. Our protocols do not assume trusted setup or public key infrastructure and converge to the perfect coin exponentially fast in the protocol running time. By plugging one of our protocols for Monte Carlo common coin in a well-known consensus algorithm, we manage to get a binary Byzantine agreement protocol with O(n³ log n) communication complexity, resilient against an adaptive adversary, and tolerating the optimal number f < n/3 of failures without trusted setup or PKI. To the best of our knowledge, the best communication complexity for binary Byzantine agreement achieved so far in this setting is O(n⁴). We also show how the approximate common coin, combined with a variant of Gray code, can be used to solve an interesting problem of Intersecting Random Subsets, which we introduce in this paper.

Cite as

Luciano Freitas, Petr Kuznetsov, and Andrei Tonkikh. Distributed Randomness from Approximate Agreement. In 36th International Symposium on Distributed Computing (DISC 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 246, pp. 24:1-24:21, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)


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@InProceedings{freitas_et_al:LIPIcs.DISC.2022.24,
  author =	{Freitas, Luciano and Kuznetsov, Petr and Tonkikh, Andrei},
  title =	{{Distributed Randomness from Approximate Agreement}},
  booktitle =	{36th International Symposium on Distributed Computing (DISC 2022)},
  pages =	{24:1--24:21},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-255-6},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{246},
  editor =	{Scheideler, Christian},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.DISC.2022.24},
  URN =		{urn:nbn:de:0030-drops-172157},
  doi =		{10.4230/LIPIcs.DISC.2022.24},
  annote =	{Keywords: Asynchronous, approximate agreement, weak common coin, consensus, Byzantine agreement}
}
Document
RandSolomon: Optimally Resilient Random Number Generator with Deterministic Termination

Authors: Luciano Freitas de Souza, Andrei Tonkikh, Sara Tucci-Piergiovanni, Renaud Sirdey, Oana Stan, Nicolas Quero, and Petr Kuznetsov

Published in: LIPIcs, Volume 217, 25th International Conference on Principles of Distributed Systems (OPODIS 2021)


Abstract
Multi-party random number generation is a key building-block in many practical protocols. While straightforward to solve when all parties are trusted to behave correctly, the problem becomes much more difficult in the presence of faults. This paper presents RandSolomon, a partially synchronous protocol that allows a system of N processes to produce an unpredictable common random number shared by correct participants. The protocol is optimally resilient, as it allows up to f = ⌊(N-1)/3⌋ of the processes to behave arbitrarily, ensures deterministic termination and, contrary to prior solutions, does not, at any point, expect faulty processes to be responsive.

Cite as

Luciano Freitas de Souza, Andrei Tonkikh, Sara Tucci-Piergiovanni, Renaud Sirdey, Oana Stan, Nicolas Quero, and Petr Kuznetsov. RandSolomon: Optimally Resilient Random Number Generator with Deterministic Termination. In 25th International Conference on Principles of Distributed Systems (OPODIS 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 217, pp. 23:1-23:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)


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@InProceedings{freitasdesouza_et_al:LIPIcs.OPODIS.2021.23,
  author =	{Freitas de Souza, Luciano and Tonkikh, Andrei and Tucci-Piergiovanni, Sara and Sirdey, Renaud and Stan, Oana and Quero, Nicolas and Kuznetsov, Petr},
  title =	{{RandSolomon: Optimally Resilient Random Number Generator with Deterministic Termination}},
  booktitle =	{25th International Conference on Principles of Distributed Systems (OPODIS 2021)},
  pages =	{23:1--23:16},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-219-8},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{217},
  editor =	{Bramas, Quentin and Gramoli, Vincent and Milani, Alessia},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.OPODIS.2021.23},
  URN =		{urn:nbn:de:0030-drops-157986},
  doi =		{10.4230/LIPIcs.OPODIS.2021.23},
  annote =	{Keywords: Byzantine Fault Tolerance, Partially Synchronous, Deterministic Termination, Randomness Beacon, Multi Party Computation, BFT-RNG}
}
Document
Accountability and Reconfiguration: Self-Healing Lattice Agreement

Authors: Luciano Freitas de Souza, Petr Kuznetsov, Thibault Rieutord, and Sara Tucci-Piergiovanni

Published in: LIPIcs, Volume 217, 25th International Conference on Principles of Distributed Systems (OPODIS 2021)


Abstract
An accountable distributed system provides means to detect deviations of system components from their expected behavior. It is natural to complement fault detection with a reconfiguration mechanism, so that the system could heal itself, by replacing malfunctioning parts with new ones. In this paper, we describe a framework that can be used to implement a large class of accountable and reconfigurable replicated services. We build atop the fundamental lattice agreement abstraction lying at the core of storage systems and cryptocurrencies. Our asynchronous implementation of accountable lattice agreement ensures that every violation of consistency is followed by an undeniable evidence of misbehavior of a faulty replica. The system can then be seamlessly reconfigured by evicting faulty replicas, adding new ones and merging inconsistent states. We believe that this paper opens a direction towards asynchronous "self-healing" systems that combine accountability and reconfiguration.

Cite as

Luciano Freitas de Souza, Petr Kuznetsov, Thibault Rieutord, and Sara Tucci-Piergiovanni. Accountability and Reconfiguration: Self-Healing Lattice Agreement. In 25th International Conference on Principles of Distributed Systems (OPODIS 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 217, pp. 25:1-25:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)


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@InProceedings{freitasdesouza_et_al:LIPIcs.OPODIS.2021.25,
  author =	{Freitas de Souza, Luciano and Kuznetsov, Petr and Rieutord, Thibault and Tucci-Piergiovanni, Sara},
  title =	{{Accountability and Reconfiguration: Self-Healing Lattice Agreement}},
  booktitle =	{25th International Conference on Principles of Distributed Systems (OPODIS 2021)},
  pages =	{25:1--25:23},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-219-8},
  ISSN =	{1868-8969},
  year =	{2022},
  volume =	{217},
  editor =	{Bramas, Quentin and Gramoli, Vincent and Milani, Alessia},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.OPODIS.2021.25},
  URN =		{urn:nbn:de:0030-drops-158007},
  doi =		{10.4230/LIPIcs.OPODIS.2021.25},
  annote =	{Keywords: Reconfiguration, accountability, asynchronous, lattice agreement}
}
Document
Brief Announcement
Brief Announcement: Accountability and Reconfiguration — Self-Healing Lattice Agreement

Authors: Luciano Freitas de Souza, Petr Kuznetsov, Thibault Rieutord, and Sara Tucci-Piergiovanni

Published in: LIPIcs, Volume 209, 35th International Symposium on Distributed Computing (DISC 2021)


Abstract
An accountable distributed system provides means to detect deviations of system components from their expected behavior. It is natural to complement fault detection with a reconfiguration mechanism, so that the system could heal itself, by replacing malfunctioning parts with new ones. In this paper, we describe a framework that can be used to implement a large class of accountable and reconfigurable replicated services. We build atop the fundamental lattice agreement abstraction lying at the core of storage systems and cryptocurrencies. Our asynchronous implementation of accountable lattice agreement ensures that every violation of consistency is followed by an undeniable evidence of misbehavior of a faulty replica. The system can then be seamlessly reconfigured by evicting faulty replicas, adding new ones and merging inconsistent states. We believe that this paper opens a direction towards asynchronous "self-healing" systems that combine accountability and reconfiguration.

Cite as

Luciano Freitas de Souza, Petr Kuznetsov, Thibault Rieutord, and Sara Tucci-Piergiovanni. Brief Announcement: Accountability and Reconfiguration — Self-Healing Lattice Agreement. In 35th International Symposium on Distributed Computing (DISC 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 209, pp. 54:1-54:5, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)


Copy BibTex To Clipboard

@InProceedings{desouza_et_al:LIPIcs.DISC.2021.54,
  author =	{de Souza, Luciano Freitas and Kuznetsov, Petr and Rieutord, Thibault and Tucci-Piergiovanni, Sara},
  title =	{{Brief Announcement: Accountability and Reconfiguration — Self-Healing Lattice Agreement}},
  booktitle =	{35th International Symposium on Distributed Computing (DISC 2021)},
  pages =	{54:1--54:5},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-210-5},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{209},
  editor =	{Gilbert, Seth},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.DISC.2021.54},
  URN =		{urn:nbn:de:0030-drops-148565},
  doi =		{10.4230/LIPIcs.DISC.2021.54},
  annote =	{Keywords: Reconfiguration, accountability, asynchronous, lattice agreement}
}
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