eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Leibniz International Proceedings in Informatics
1868-8969
2021-10-04
32:1
32:16
10.4230/LIPIcs.DISC.2021.32
article
Optimal Communication Complexity of Authenticated Byzantine Agreement
Momose, Atsuki
1
2
Ren, Ling
3
Nagoya University, Aichi, Japan
Intelligent Systems Laboratory, SECOM CO.,LTD., Tokyo, Japan
University of Illinois at Urbana-Champaign, Urbana, IL, USA
Byzantine Agreement (BA) is one of the most fundamental problems in distributed computing, and its communication complexity is an important efficiency metric. It is well known that quadratic communication is necessary for BA in the worst case due to a lower bound by Dolev and Reischuk. This lower bound has been shown to be tight for the unauthenticated setting with f < n/3 by Berman et al. but a considerable gap remains for the authenticated setting with n/3 ≤ f < n/2.
This paper provides two results towards closing this gap. Both protocols have a quadratic communication complexity and have different trade-offs in resilience and assumptions. The first protocol achieves the optimal resilience of f < n/2 but requires a trusted setup for threshold signature. The second protocol achieves near optimal resilience f ≤ (1/2 - ε)n in the standard PKI model.
https://drops.dagstuhl.de/storage/00lipics/lipics-vol209-disc2021/LIPIcs.DISC.2021.32/LIPIcs.DISC.2021.32.pdf
Byzantine Agreement
Communication Complexity
Lower Bound