This Article 
 Bibliographic References 
 Add to: 
hBFT: Speculative Byzantine Fault Tolerance With Minimum Cost
ISSN: 1545-5971
Sisi Duan, Sisi Duan is with the Department of Computer Science, University of California, Davis, Davis, CA, USA.(
We present hBFT, a hybrid, Byzantine fault-tolerant, replicated state machine protocol with optimal resilience. Under normal circumstances, hBFT uses speculation, i.e., replicas directly adopt the order from the primary and send replies to the clients. As in prior work such as Zyzzyva, when replicas are out of order, clients can detect the inconsistency and help replicas converge on the total ordering. However, we take a different approach than previous work that has four distinct benefits: it requires many fewer cryptographic operations, it moves critical jobs to the clients with no additional costs, faulty clients can be detected and identified, and performance in the presence of client participation will not degrade as long as the primary is correct. The correctness is guaranteed by a three-phase checkpoint subprotocol similar to PBFT, which is tailored to our needs. The protocol is triggered by the primary when a certain number of requests are executed or by clients when they detect an inconsistency.
Sean Peisert, Karl Levitt, Sisi Duan, "hBFT: Speculative Byzantine Fault Tolerance With Minimum Cost," IEEE Transactions on Dependable and Secure Computing, 24 March 2014. IEEE computer Society Digital Library. IEEE Computer Society, <>
Usage of this product signifies your acceptance of the Terms of Use.