TY - JOUR T1 - On expected constant-round protocols for Byzantine agreement JF - Journal of Computer and System Sciences Y1 - 2009 A1 - Katz, Jonathan A1 - Koo,Chiu-Yuen KW - broadcast KW - cryptography KW - Distributed computing KW - secure computation AB - In a seminal paper, Feldman and Micali show an n-party Byzantine agreement protocol in the plain model that tolerates t < n / 3 malicious parties and runs in expected constant rounds. Here, resolving a question that had been open since their work, we show an expected constant-round protocol for authenticated Byzantine agreement assuming honest majority (i.e., t < n / 2 ), and relying only on the existence of signature schemes and a public-key infrastructure. Combined with existing results, this gives the first expected constant-round protocol for secure computation with honest majority in a point-to-point network under the same assumptions. Our key technical tool — a new primitive we introduce called moderated VSS — also yields a simpler proof of the Feldman–Micali result.In addition, we show a simple technique for sequential composition of Byzantine agreement protocols that do not achieve simultaneous termination, something that is inherent for protocols using o ( t ) rounds. VL - 75 SN - 0022-0000 UR - http://www.sciencedirect.com/science/article/pii/S0022000008000718 CP - 2 M3 - 10.1016/j.jcss.2008.08.001 ER -