VOTING MECHANISMS IN ASYNCHRONOUS BYZANTINE ENVIRONMENTS
Andrzej Pelc · Parallel Processing Letters · 2006
A source sends a piece of data (message), relayed to a receiver by n processes, some of which can be faulty. We assume that the number of faulty processes is at most f and that faulty processes exhibit a Byzantine behavior. A deciding agent has to make a decision concerning the source message, on the basis of results obtained from the receiver. The environment is totally asynchronous. An Asynchronous Byzantine Voting Mechanism is a method that enables the deciding agent to always correctly determine the source message in this scenario. We show that there exists a correct Asynchronous Byzantine Voting Mechanism if and only if f < n/3. If this condition is satisfied, we provide such a mechanism. This result should be contrasted with the feasibility of synchronous voting mechansisms, in which the receiver can wait until all fault-free processes convey their values: for this scenario a correct voting mechanism exists whenever f < n/2.