4 Search Results for "Lecl�re, Michel"

Document
DOI: 10.4230/LIPIcs.OPODIS.2022.26
A Modular Approach to Construct Signature-Free BRB Algorithms Under a Message Adversary

Authors: Timothé Albouy, Davide Frey, Michel Raynal, and François Taïani

Published in: LIPIcs, Volume 253, 26th International Conference on Principles of Distributed Systems (OPODIS 2022)

Abstract
This paper explores how reliable broadcast can be implemented without signatures when facing a dual adversary that can both corrupt processes and remove messages. More precisely, we consider an asynchronous n-process message-passing system in which up to t processes are Byzantine and where, at the network level, for each message broadcast by a correct process, an adversary can prevent up to d processes from receiving it (the integer d defines the power of the message adversary). So, unlike previous works, this work considers that not only can computing entities be faulty (Byzantine processes), but, in addition, that the network can also lose messages. To this end, the paper adopts a modular strategy and first introduces a new basic communication abstraction denoted k2𝓁-cast, which simplifies quorum engineering, and studies its properties in this new adversarial context. Then, the paper deconstructs existing signature-free Byzantine-tolerant asynchronous broadcast algorithms and, with the help of the k2𝓁-cast communication abstraction, reconstructs versions of them that tolerate both Byzantine processes and message adversaries. Interestingly, these reconstructed algorithms are also more efficient than the Byzantine-tolerant-only algorithms from which they originate.
Cite as

Timothé Albouy, Davide Frey, Michel Raynal, and François Taïani. A Modular Approach to Construct Signature-Free BRB Algorithms Under a Message Adversary. In 26th International Conference on Principles of Distributed Systems (OPODIS 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 253, pp. 26:1-26:23, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2023)

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@InProceedings{albouy_et_al:LIPIcs.OPODIS.2022.26,
  author =	{Albouy, Timoth\'{e} and Frey, Davide and Raynal, Michel and Ta\"{i}ani, Fran\c{c}ois},
  title =	{{A Modular Approach to Construct Signature-Free BRB Algorithms Under a Message Adversary}},
  booktitle =	{26th International Conference on Principles of Distributed Systems (OPODIS 2022)},
  pages =	{26:1--26:23},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-265-5},
  ISSN =	{1868-8969},
  year =	{2023},
  volume =	{253},
  editor =	{Hillel, Eshcar and Palmieri, Roberto and Rivi\`{e}re, Etienne},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.OPODIS.2022.26},
  URN =		{urn:nbn:de:0030-drops-176464},
  doi =		{10.4230/LIPIcs.OPODIS.2022.26},
  annote =	{Keywords: Asynchronous system, Byzantine processes, Communication abstraction, Delivery predicate, Fault-Tolerance, Forwarding predicate, Message adversary, Message loss, Modularity, Quorum, Reliable broadcast, Signature-free algorithm, Two-phase commit}
}
Document
DOI: 10.4230/LIPIcs.CP.2021.13
On How Turing and Singleton Arc Consistency Broke the Enigma Code

Authors: Valentin Antuori, Tom Portoleau, Louis Rivière, and Emmanuel Hebrard

Published in: LIPIcs, Volume 210, 27th International Conference on Principles and Practice of Constraint Programming (CP 2021)

Abstract
In this paper, we highlight an intriguing connection between the cryptographic attacks on Enigma’s code and local consistency reasoning in constraint programming. The coding challenge proposed to the students during the 2020 ACP summer school, to be solved by constraint programming, was to decipher a message encoded using the well known Enigma machine, with as only clue a tiny portion of the original message. A number of students quickly crafted a model, thus nicely showcasing CP technology - as well as their own brightness. The detail that is slightly less favorable to CP technology is that solving this model on modern hardware is challenging, whereas the "Bombe", an antique computing device, could solve it eighty years ago. We argue that from a constraint programming point of vue, the key aspects of the techniques designed by Polish and British cryptanalysts can be seen as, respectively, path consistency and singleton arc consistency on some constraint satisfaction problems.
Cite as

Valentin Antuori, Tom Portoleau, Louis Rivière, and Emmanuel Hebrard. On How Turing and Singleton Arc Consistency Broke the Enigma Code. In 27th International Conference on Principles and Practice of Constraint Programming (CP 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 210, pp. 13:1-13:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021)

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@InProceedings{antuori_et_al:LIPIcs.CP.2021.13,
  author =	{Antuori, Valentin and Portoleau, Tom and Rivi\`{e}re, Louis and Hebrard, Emmanuel},
  title =	{{On How Turing and Singleton Arc Consistency Broke the Enigma Code}},
  booktitle =	{27th International Conference on Principles and Practice of Constraint Programming (CP 2021)},
  pages =	{13:1--13:16},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-211-2},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{210},
  editor =	{Michel, Laurent D.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.CP.2021.13},
  URN =		{urn:nbn:de:0030-drops-153040},
  doi =		{10.4230/LIPIcs.CP.2021.13},
  annote =	{Keywords: Constraint Programming, Cryptography}
}
Document
DOI: 10.4230/LIPIcs.ICDT.2019.18
A Single Approach to Decide Chase Termination on Linear Existential Rules

Authors: Michel Leclère, Marie-Laure Mugnier, Michaël Thomazo, and Federico Ulliana

Published in: LIPIcs, Volume 127, 22nd International Conference on Database Theory (ICDT 2019)

Abstract
Existential rules, long known as tuple-generating dependencies in database theory, have been intensively studied in the last decade as a powerful formalism to represent ontological knowledge in the context of ontology-based query answering. A knowledge base is then composed of an instance that contains incomplete data and a set of existential rules, and answers to queries are logically entailed from the knowledge base. This brought again to light the fundamental chase tool, and its different variants that have been proposed in the literature. It is well-known that the problem of determining, given a chase variant and a set of existential rules, whether the chase will halt on any instance, is undecidable. Hence, a crucial issue is whether it becomes decidable for known subclasses of existential rules. In this work, we consider linear existential rules with atomic head, a simple yet important subclass of existential rules that generalizes inclusion dependencies. We show the decidability of the all-instance chase termination problem on these rules for three main chase variants, namely semi-oblivious, restricted and core chase. To obtain these results, we introduce a novel approach based on so-called derivation trees and a single notion of forbidden pattern. Besides the theoretical interest of a unified approach and new proofs for the semi-oblivious and core chase variants, we provide the first positive decidability results concerning the termination of the restricted chase, proving that chase termination on linear existential rules with atomic head is decidable for both versions of the problem: Does every chase sequence terminate? Does some chase sequence terminate?
Cite as

Michel Leclère, Marie-Laure Mugnier, Michaël Thomazo, and Federico Ulliana. A Single Approach to Decide Chase Termination on Linear Existential Rules. In 22nd International Conference on Database Theory (ICDT 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 127, pp. 18:1-18:19, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)

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@InProceedings{leclere_et_al:LIPIcs.ICDT.2019.18,
  author =	{Lecl\`{e}re, Michel and Mugnier, Marie-Laure and Thomazo, Micha\"{e}l and Ulliana, Federico},
  title =	{{A Single Approach to Decide Chase Termination on Linear Existential Rules}},
  booktitle =	{22nd International Conference on Database Theory (ICDT 2019)},
  pages =	{18:1--18:19},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-101-6},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{127},
  editor =	{Barcelo, Pablo and Calautti, Marco},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2019.18},
  URN =		{urn:nbn:de:0030-drops-103200},
  doi =		{10.4230/LIPIcs.ICDT.2019.18},
  annote =	{Keywords: Chase, Tuple Generating Dependencies, Existential rules, Decidability}
}
Document
DOI: 10.4230/DagSemProc.05081.2
Architectural Views for CommUnity

Authors: Cristóvão Oliveira and Michel Wermelinger

Published in: Dagstuhl Seminar Proceedings, Volume 5081, Foundations of Global Computing (2006)

Abstract
CommUnity and its categorical foundations provide a formal approach to Software Architecture (SA). Several concepts such as (re) configuration and (higher-order) connector have been given precise definitions in this setting. One of the cornerstones of the approach is the separation between computation, coordination and distribution. In this paper, we take this separation one step further and define explicit architectural views, one for each concern. They will be used to help to detect errors made while building the architecture. Moreover they will be a support to improve the design of the system by focusing on one concern at a time and/or by combining them with each other.
Cite as

Cristóvão Oliveira and Michel Wermelinger. Architectural Views for CommUnity. In Foundations of Global Computing. Dagstuhl Seminar Proceedings, Volume 5081, pp. 1-3, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2006)

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@InProceedings{oliveira_et_al:DagSemProc.05081.2,
  author =	{Oliveira, Crist\'{o}v\~{a}o and Wermelinger, Michel},
  title =	{{Architectural Views for CommUnity}},
  booktitle =	{Foundations of Global Computing},
  pages =	{1--3},
  series =	{Dagstuhl Seminar Proceedings (DagSemProc)},
  ISSN =	{1862-4405},
  year =	{2006},
  volume =	{5081},
  editor =	{Jos\'{e} Luiz Fiadeiro and Ugo Montanari and Martin Wirsing},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops-dev.dagstuhl.de/entities/document/10.4230/DagSemProc.05081.2},
  URN =		{urn:nbn:de:0030-drops-2967},
  doi =		{10.4230/DagSemProc.05081.2},
  annote =	{Keywords: Software Architecture, views, computation, coordination, distribution}
}
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