2026-07-21T12:18:28Z https://drops.dagstuhl.de/oai

oai:drops-oai.dagstuhl.de:24818 2026-02-09T07:41:27Z ddc:004 open_access

ABEL: Perfect Asynchronous Byzantine Extension from List-Decoding Abraham, Ittai Asharov, Gilad Asynchronous Byzantine Agreement Perfect Security Asynchronous byzantine agreement extension studies the message complexity of L-bit multivalued asynchronous byzantine agreement given access to a binary asynchronous Byzantine agreement protocol. We prove that asynchronous byzantine agreement extension can be solved with perfect security and optimal resilience in O(nL+n² log n) total communication (in bits) in addition to a single call to a binary asynchronous Byzantine agreement protocol. For L = O(n log n), this gives an asymptotically optimal protocol, resolving a question that remained open for nearly two decades. List decoding is a fundamental concept in theoretical computer science and cryptography, enabling error correction beyond the unique decoding radius and playing a critical role in constructing robust codes, hardness amplification, and secure cryptographic protocols. A key novelty of our perfectly secure and optimally resilient asynchronous byzantine agreement extension protocol is that it uses list decoding - making a striking new connection between list decoding and asynchronous Byzantine agreement. Schloss Dagstuhl – Leibniz-Zentrum für Informatik Ittai Abraham and Gilad Asharov 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.2025.1 urn:nbn:de:0030-drops-248185 https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.DISC.2025.1 eng https://creativecommons.org/licenses/by/4.0/legalcode