A paper coauthored by Professor and Cheriton Chair N. Asokan has received the 2019 Best Paper Award from IEEE Transactions on Computers by the IEEE Computer Society Publications Board.
Tilted Scalable Byzantine Consensus via Hardware-assisted Secret Sharing, the award-winning paper by Jian Liu, Wenting Li, Ghassan Karame and N. Asokan describes and evaluates FastBFT, a fast and scalable Byzantine fault-tolerant protocol.
Study authors left to right: Jian Liu, Assistant Professor at Zhejiang University, who received his doctorate at Finland’s Aalto University and was supervised by Asokan; Wenting Li, Senior Software Developer at NEC Laboratories Europe; Ghassan Karame, Manager and Chief researcher of Security Group of NEC Laboratories Europe; and N. Asokan, Professor and Cheriton Chair at the David R. Cheriton School of Computer Science.
Byzantine fault-tolerant or BFT protocols are able continue operating even in the event of failures within the protocol. Byzantine fault-tolerance is the gold standard in systems that are critically important for human safety as well as those that need to be highly reliable, available, and secure.
However, despite the need for BFT protocols they have not been deployed widely. A number of technical obstacles have limited their widespread adoption, but perhaps the greatest is that BFT protocols scale poorly because of their computational and communication complexity.
Recent interest in blockchains has revived interest in BFT protocols. A blockchain serves as a ledger for digital currencies such as Bitcoin and Ethereum, as well as many other applications where an immutable digital ledger is needed to keep track of records and transactions. Distributed consensus is a key enabler for such ledgers.
In their paper, Asokan and his colleagues describe and evaluate FastBFT. At the heart of FastBFT is a novel message aggregation technique that combines hardware-based trusted execution environments with lightweight secret sharing. Aggregation reduces message complexity, which makes the protocol much more computationally efficient and scalable.
Their experiments revealed that the throughput of FastBFT is significantly larger than prior BFT protocols. Moreover, as the number of nodes increased, FastBFT had considerably slower decline in throughput, making FastBFT an attractive consensus layer candidate for next-generation permissioned blockchain systems. Since their paper was published, FastBFT has attracted interest from both practitioners and industry.
Asokan and his students continue to build on their fast Byzantine fault-tolerant protocols at ICRI-CARS — the Intel Collaborative Research Institutes Collaborative Autonomous Research Systems. ICRI-CARS explores security issues in autonomous systems and includes amongst its partners the University of Waterloo. FastBFT relied on every participating system being equipped with a hardware-based trusted execution environment. However, in long-lived autonomous systems this assumption may not hold. In their follow-up work at ICRI-CARS, Asokan and his co-authors developed a resilient but efficient BFT protocol that requires only one active system to have the requisite hardware support.
To learn more about their research, please see J. Liu, W. Li, G. O. Karame and N. Asokan, “Scalable Byzantine Consensus via Hardware-Assisted Secret Sharing,” IEEE Transactions on Computers, 68(1):139–51, January 2019, doi: 10.1109/TC.2018.2860009.