A New Way to Achieve Round-Efficient Byzantine Agreement

Abstract

Minimizing the round complexity of Byzantine Agreement (BA) protocols is a fundamental problem in distributed computing. The typical approach to achieve round efficient (randomized) BA is to have a weak form of BA, called graded consensus (GC), followed by a distributed coin, and to repeat this process until some termination condition is met-as introduced by Feldman and Micali (STOC '88).In this work, we revisit the question of building BA from GC, or, more precisely, from generalizations of GC. Concretely, for 'Monte Carlo' style BA, where the protocol is run for a fixed number of rounds in function of the security parameter (in contrast to protocols with probabilistic termination), we demonstrate that this generalization helps to considerably reduce the round complexity of BA.In particular, assuming a setup for threshold signatures among the parties and corruption threshold t < n/3, we improve over the round complexity of the best known protocol by a factor of 1/2, asymptotically; this is achieved by applying one single Feldman-Micali iteration consisting of one (generalized) GC instance and one round of coin tossing.Our technique also applies to the dishonest-minority case (t < n/2), yielding an improvement by a factor of 1/4 (asymptotically) over the round complexity of the best known fixed-round protocol. CCS CONCEPTS• Theory of computation → Cryptographic protocols.

FP‐BFT: A fast pipeline Byzantine consensus algorithm

“…However, the above algorithms still rely on the leader node for message broadcasting and forwarding, therefore its performance is constrained by the leader node. Some researchers improve the consensus efficiency by optimizing the structure [22][23][24][25][26]. Li et al proposed the SHBFT [22] algorithm, and Li et al proposed the EBFT [23]algorithm, both of which optimize the network topology to reduce the costs of communications, increase the scalability.…”