Active Quorum Systems
Source: Universidade de Coimbra
This paper outlines a flexible suite of object replication protocols that brings together Byzantine quorum systems registers and state machine replication. These protocols enable the implementation of Byzantine fault-tolerant applications that make minimal assumptions about the environment and that run in at most two more communication steps in almost all cases of non-favorable executions (in comparison with favorable executions). The existence of much work on Byzantine Fault-Tolerant (BFT) read/write protocols, most practical work on BFT replication is based on the notion of replicas as state machines that evolve in a coordinated way, which can be very restrictive for practical applications.