Round efficiency of multi-party computation with a dishonest majority

Jonathan Katz, Rafail Ostrovsky, Adam Smith

Research output: Contribution to journalArticle

40 Scopus citations


We consider the round complexity of multi-party computation in the presence of a static adversary who controls a majority of the parties. Here, n players wish to securely compute some functionality and up to n - 1 of these players may be arbitrarily malicious. Previous protocols for this setting (when a broadcast channel is available) require O(n) rounds. We present two protocols with improved round complexity: The first assumes only the existence of trapdoor permutations and dense cryptosystems, and achieves round complexity O(log n) based on a proof scheduling technique of Chor and Rabin [13]; the second requires a stronger hardness assumption (along with the non-black-box techniques of Barak [2]) and achieves O(1) round complexity.

Original languageEnglish (US)
Pages (from-to)578-595
Number of pages18
JournalLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
StatePublished - Dec 1 2003


All Science Journal Classification (ASJC) codes

  • Theoretical Computer Science
  • Computer Science(all)

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