2026-08-03T00:29:26Z https://drops.dagstuhl.de/oai

oai:drops-oai.dagstuhl.de:13107 2024-03-06T10:51:35Z ddc:004 open_access

From Partial to Global Asynchronous Reliable Broadcast Ghinea, Diana Hirt, Martin Liu-Zhang, Chen-Da asynchronous broadcast partial broadcast Broadcast is a fundamental primitive in distributed computing. It allows a sender to consistently distribute a message among n recipients. The seminal result of Pease et al. [JACM'80] shows that in a complete network of synchronous bilateral channels, broadcast is achievable if and only if the number of corruptions is bounded by t < n/3. To overcome this bound, a fascinating line of works, Fitzi and Maurer [STOC'00], Considine et al. [JC'05], and Raykov [ICALP'15], proposed strengthening the communication network by assuming partial synchronous broadcast channels, which guarantee consistency among a subset of recipients. We extend this line of research to the asynchronous setting. We consider reliable broadcast protocols assuming a communication network which provides each subset of b parties with reliable broadcast channels. A natural question is to investigate the trade-off between the size b and the corruption threshold t. We answer this question by showing feasibility and impossibility results: - A reliable broadcast protocol Π_{RBC} that: - For 3 ≤ b ≤ 4, is secure up to t < n/2 corruptions. - For b > 4 even, is secure up to t < ((b-4)/(b-2) n + 8/(b-2)) corruptions. - For b > 4 odd, is secure up to t < ((b-3)/(b-1) n + 6/(b-1)) corruptions. - A nonstop reliable broadcast Π_{nRBC}, where parties are guaranteed to obtain output as in reliable broadcast but may need to run forever, secure up to t < (b-1)/(b+1) n corruptions. - There is no protocol for (nonstop) reliable broadcast secure up to t ≥ (b-1)/(b+1) n corruptions, implying that Π_{RBC} is an asymptotically optimal reliable broadcast protocol, and Π_{nRBC} is an optimal nonstop reliable broadcast protocol. Schloss Dagstuhl – Leibniz-Zentrum für Informatik Diana Ghinea and Martin Hirt and Chen-Da Liu-Zhang 2020 Is Part Of LIPIcs, Volume 179, 34th International Symposium on Distributed Computing (DISC 2020) InProceedings Text doc-type:ResearchArticle publishedVersion application/pdf doi:10.4230/LIPIcs.DISC.2020.29 urn:nbn:de:0030-drops-131074 https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.DISC.2020.29 eng https://creativecommons.org/licenses/by/3.0/legalcode