Linear View-Change BFT with Optimistic Responsiveness

A non-transitory computer readable storage medium having stored thereon program code embodying a method for implementing linear view-change with optimistic responsiveness in a Byzantine Fault Tolerant (BFT) protocol running on a distributed system comprising n replicas, wherein no more than f of the n replicas are faulty, and wherein the BFT protocol enables at least 2f+1 of the n replicas to agree on how to sequence execution of a plurality of service operations originating from one or more clients, the method comprising:

• executing, by the n replicas during a view v of the BFT protocol, a first voting round comprising communicating instances of a first type of COMMIT certificate among the n replicas;
• when 2f+1 instances of the first type of COMMIT certificate associated with the view v have been received by the n replicas, executing a second voting round comprising communicating instances of a second type of COMMIT certificate among the n replicas;
• and
• if 2f+1 instances of the second type of COMMIT certificate associated with the view v are not received by the n replicas within a predetermined timeout period, initiating a view-change from the view v to a view v+1.

A distributed system comprising:

• n replicas;
• and
• a non-transitory computer readable medium having stored thereon program code that, when executed, enables the distributed system to implement linear view-change with optimistic responsiveness in a Byzantine Fault Tolerant (BFT) protocol running on the distributed system, wherein no more than f of the n replicas are faulty, and wherein the BFT protocol enables at least 2f+1 of the n replicas to agree on how to sequence execution of a plurality of service operations originating from one or more clients, the program code causing the distributed system to:
• execute, during a view v of the BFT protocol, a first voting round comprising communicating instances of a first type of COMMIT certificate among the n replicas;
• when 2f+1 instances of the first type of COMMIT certificate associated with the view v have been received by the n replicas, execute a second voting round comprising communicating instances of a second type of COMMIT certificate among the n replicas;
• and
• if 2f+1 instances of the second type of COMMIT certificate associated with the view v are not received by the n replicas within a predetermined timeout period, initiate a view-change from the view v to a view v+1.