Randomized Distributed Agreement (Extended Abstract)

Distributed Agreement (DA) is one of the fundamental problems in the theory and practice of fault-tolerant distributed systems. It requires correct processors (agents, players) to agree on an initial value held by one of them, despite the (even malicious) behavior of a subset of size t. A randomized solution to the problem achieves agreement with a high probability after a constant number of communication rounds. In this paper we present a succint and efficient randomized DA protocol for asynchronous networks that works for n > 5t processors, where n is the size of the network. The protocol has low communication complexity (@(log n) message size) and does not require any cryptographic assumption. The protocol belongs to the class of protocols that require a “trusted dealer,” who is in charge of a suitable network initialization, and represents an improvement in terms of number of processors to previous solutions presented in [17, 18, 201. We contrast our approach to the class of protocols that are currently able to perform randomized agreement from scratch, an unlimited number of times (e.g., [14]), but have