Algorithm

The normal execution path is primarily derived from the PBFT paper. As in the paper, we assume that the system asynchronous and distributed where nodes are connected by a network. The network may fail to deliver messages, delay them, duplicate them, or deliver them out of order. We use a Byzantine failure model, i.e., faulty nodes may behave arbitrarily.

The algorithm is used to implement a deterministic replicated service with a state. Clients issue requests to the replicated service and wait for a reply. The replicated service is implemented by n replicas (nodes). The algorithm provides both safety and liveness assuming no more than replicas are faulty. The next figure