Abstract: A fault-tolerant replication system includes a first machine running a first hypervisor. A second machine is failure-independent of the first machine. The second machine runs a second hypervisor. A first plurality of virtual machines runs on the first hypervisor. A second plurality of virtual machines runs on the second hypervisor. Each of the virtual machines of the first and second plurality of virtual machines constitutes either a virtual machine replica server of a fault-tolerant replicated state machine or a backup corresponding to a virtual machine replica server of the fault-tolerant replicated state machine. Every backup is embodied on a different machine, of the first and second machines, from its corresponding virtual machine replica server.

Abstract: A system for automatically monitoring and controlling an infrastructure or process includes a plurality of remote clients installed along various portions of an industrial infrastructure or an infrastructure performing a process. Each of the remote clients collects data. A plurality of server replicas is in communication with the plurality of remote clients. The server replicas receive the collected data from the remote clients and process the received data. The plurality of remote clients and the plurality of server replicas communicate across an electronic network. The plurality of server replicas includes a state machine replication system that is tolerant of a failure of one or more of the server replicas.

Abstract: A network of replicated servers providing a service includes a plurality of server replicas. A leader is elected from among the plurality of server replicas for coordinating ordering of operations among the plurality of server replicas. A view change protocol is executed by the plurality of server replicas after the election of the leader. Each iteration of the view change protocol corresponds to a unique view number. The server replicas are directed by the view change protocol to cooperate to order operations by exchange of information associated with particular view numbers. The information is prioritized in accordance with the view numbers. The non-leaders monitor the response time of the leader and elect a new leader when it is determined that the monitored length of time is greater than a threshold value that is dependent upon current network conditions.

Abstract: A system for automatically monitoring and controlling an infrastructure or process includes a plurality of remote clients installed along various portions of an industrial infrastructure or an infrastructure performing a process. Each of the remote clients collects data. A plurality of server replicas is in communication with the plurality of remote clients. The server replicas receive the collected data from the remote clients and process the received data. The plurality of remote clients and the plurality of server replicas communicate across an electronic network. The plurality of server replicas includes a state machine replication system that is tolerant of a failure of one or more of the server replicas.

Abstract: A fault-tolerant replication system includes a first machine running a first hypervisor. A second machine is failure-independent of the first machine. The second machine runs a second hypervisor. A first plurality of virtual machines runs on the first hypervisor. A second plurality of virtual machines runs on the second hypervisor. Each of the virtual machines of the first and second plurality of virtual machines constitutes either a virtual machine replica server of a fault-tolerant replicated state machine or a backup corresponding to a virtual machine replica server of the fault-tolerant replicated state machine. Every backup is embodied on a different machine, of the first and second machines, from its corresponding virtual machine replica server.

Abstract: A network of replicated servers providing a service includes a plurality of server replicas. A leader is elected from among the plurality of server replicas for coordinating ordering of operations among the plurality of server replicas. A view change protocol is executed by the plurality of server replicas after the election of the leader. Each iteration of the view change protocol corresponds to a unique view number. The server replicas are directed by the view change protocol to cooperate to order operations by exchange of information associated with particular view numbers. The information is prioritized in accordance with the view numbers. The non-leaders monitor the response time of the leader and elect a new leader when it is determined that the monitored length of time is greater than a threshold value that is dependent upon current network conditions.

Abstract: An inventive system and method for intrusion-tolerant group management for a network is presented. The method comprises a client broadcasting a message request to controllers and validating the rekey messages received from the controllers, and controllers validating the client's broadcast message request and broadcasting proposals, collecting proposals, constructing threshold-signed proofs, updating the view umber, performing the client's message request, generating the rekey based on the valid proposals and transmitting the rekey to the client. Simultaneously, controllers send reconciliation messages to all controllers, based on which the membership state is updated. The client updates a shared key when a predetermined number of valid rekey messages are received. The controllers can communicate via a byzantine fault-tolerant agreement. The client can use its public key to decrypt the rekey and perform validation. The client's message request can be a join or a leave.

Abstract: An inventive system and method for intrusion-tolerant group management for a network is presented. The method comprises a client broadcasting a message request to controllers and validating the rekey messages received from the controllers, and controllers validating the client's broadcast message request and broadcasting proposals, collecting proposals, constructing threshold-signed proofs, updating the view umber, performing the client's message request, generating the rekey based on the valid proposals and transmitting the rekey to the client. Simultaneously, controllers send reconciliation messages to all controllers, based on which the membership state is updated. The client updates a shared key when a predetermined number of valid rekey messages are received. The controllers can communicate via a byzantine fault-tolerant agreement. The client can use its public key to decrypt the rekey and perform validation. The client's message request can be a join or a leave.