Efficient agreement using fault diagnosis

Abstract

We give an extremely simple Byzantine agreement protocol that uses O (t2) processors, min (f + 2, t + 1) rounds of communication, O (n ċ t ċ f ċ log |V|) total message bits, and O (log |V|) maximum message size, where n is the total number of processors that actually participate in the protocol, t is an upper bound on the number of faulty processors, f is the number of processors that actually fail in a given execution, and V is the set of possible inputs. This protocol uses roughly the same resources as a more complex protocol due to Dolev, Reischuk, and Strong. By adding explicit fault diagnosis to our first protocol, we produce a somewhat more complicated protocol that uses O(t1.5) processors, min (f + 2, t + 1) rounds, O(n ċ t2 ċ f ċ log|V|) total message bits, and O(tċ log|V|) maximum message size.