HAL : hal-00580133, version 1

DOI : 10.1145/1993806.1993810

Fiche détaillée

Récupérer au format BibTeX - EndNote - TEI - RefWorks -

PODC - 30th Annual ACM SIGACT-SIGOPS Symposium on Principles of Distributed Computing, San Jose : United States (2011)

Byzantine Agreement with Homonyms

Carole Delporte-Gallet 1, Hugues Fauconnier 1, Rachid Guerraoui 2, 3, Anne-Marie Kermarrec 4, Eric Ruppert 5, Hung Tran-The 1

(2011)

So far, the distributed computing community has either assumed that all the processes of a distributed system have distinct identifiers or, more rarely, that the processes are anonymous and have no identifiers. These are two extremes of the same general model: namely, n processes use l different authenticated identifiers, where 1 <= l <= n. In this paper, we ask how many identifiers are actually needed to reach agreement in a distributed system with $t$ Byzantine processes. We show that having 3t+1 identifiers is necessary and sufficient for agreement in the synchronous case but, more surprisingly, the number of identifiers must be greater than (n+3t)/2 in the partially synchronous case. This demonstrates two differences from the classical model (which has l=n): there are situations where relaxing synchrony to partial synchrony renders agreement impossible; and, in the partially synchronous case, increasing the number of correct processes can actually make it harder to reach agreement. The impossibility proofs use the fact that a Byzantine process can send multiple messages to the same recipient in a round. We show that removing this ability makes agreement easier: then, t+1 identifiers are sufficient for agreement, even in the partially synchronous model.

1 :	Laboratoire d'informatique Algorithmique : Fondements et Applications (LIAFA)
	CNRS : UMR7089 – Université Paris VII - Paris Diderot
2 :	Ecole Polytechnique Fédérale de Lausanne (EPFL)
	École Polytechnique Fédérale de Lausanne
3 :	Distributed Programming Laboratory (LPD)
	École Polytechnique Fédérale de Lausanne
4 :	ASAP (INRIA - IRISA)
	CNRS : UMR6074 – INRIA – Institut National des Sciences Appliquées (INSA) - Rennes – Université de Rennes 1
5 :	Department of Computer Science and Engineering [York]
	York University

Domaine

:

Sciences cognitives/Informatique

Mots Clés : Consensus – Message-Passing – Byzantine Agreement – Authentication

hal-00580133, version 1

http://hal.archives-ouvertes.fr/hal-00580133

oai:hal.archives-ouvertes.fr:hal-00580133

Contributeur : Carole Delporte-Gallet <>

Soumis le : Lundi 4 Avril 2011, 10:55:33

Dernière modification le : Vendredi 22 Février 2013, 08:54:07