2026-07-20T11:16:36Z https://drops.dagstuhl.de/oai

oai:drops-oai.dagstuhl.de:24883 2026-02-09T07:42:23Z ddc:004 open_access

Brief Announcement: Single-Round Broadcast: Impossibility, Feasibility, and More Zhou, Zhelei Zhang, Bingsheng Zhou, Hong-Sheng Ren, Kui Broadcast Security with abort Round optimality Broadcast is a fundamental primitive that plays an important role in secure Multi-Party Computation (MPC) area. In this work, we revisit the broadcast with selective abort (hereafter, short for broadcast) proposed by Goldwasser and Lindell (DISC 2002; JoC 2005) and study the round complexity of broadcast under different setup assumptions. Our findings are summarized as follows: - We formally prove that 1-round broadcast is impossible under various widely-used setup assumptions (e.g., plain model, random oracle model, and common reference string model, etc.), even if we consider the static security and the stand-alone framework. More concretely, we formalize a notion called consistent oracle to capture these setups, and prove that our impossibility holds under the consistent oracle. Our impossibility holds in both honest majority setting and dishonest majority setting. - We show that 1-round broadcast protocol is possible in the Universal Composition (UC) framework, by assuming stateful trusted hardwares. Our protocol can be proven secure against all-but-one adaptive and malicious corruptions. We bypass our impossibility result since our stateful trusted hardwares do not satisfy the definition of consistent oracle. - We provide an application of 1-round broadcast: we construct the first 1-round multiple-verifier zero-knowledge (which is a special case of MPC) protocol, without assuming the broadcast hybrid world. Schloss Dagstuhl – Leibniz-Zentrum für Informatik Zhelei Zhou and Bingsheng Zhang and Hong-Sheng Zhou and Kui Ren 2025 Is Part Of LIPIcs, Volume 356, 39th International Symposium on Distributed Computing (DISC 2025) InProceedings Text doc-type:ResearchArticle publishedVersion application/pdf doi:10.4230/LIPIcs.DISC.2025.66 urn:nbn:de:0030-drops-248838 https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.DISC.2025.66 eng https://creativecommons.org/licenses/by/4.0/legalcode