Flexible Byzantine Fault Tolerance

A few months ago, Ittai Abraham posed a challenge on whether we can have a ledger that can support "heterogeneous" clients. Independently, in a conversation, Ben Maurer asked if different transactions could be provided with different assurance levels. In a recent preliminary report on Arxiv, Dahlia, Ling and I answer these and other related questions; … Continue reading Flexible Byzantine Fault Tolerance


Dfinity Consensus, Explored

Did you ever wonder what is the BFT consensus engine that drives Dfinity, is it new or known, and how can it be improved? With co-authors at VMware Research , we explored the DFINITY Technology Overview Series on the Consensus System, and report our insights in a recent note on the Cryptology ePrint Archive .

HotStuff: Three-chain Rules!

Renewed interest in the Blockchain world on a long standing problem of asynchronous Byzantine Fault Tolerant (BFT) Consensus focuses on the following scaling challenges: Chain Quality necessitates fast/frequent proposer rotation for fairness and liveness Linearity means paying a communication cost that amounts to sending a proposal over the network once to everyone. This cost is kept … Continue reading HotStuff: Three-chain Rules!

The BFT lens: Tendermint

This is the second post in a series discussing:  Today I am going to overview the Tendermint core, a BFT algorithm described in several white-papers [tendermint wiki, Buchman's thesis 2016, Kwon's manuscript 2014]. Tendermint was the first in a series of "permissioned" blockchain BFT solutions based off PBFT, followed by Casper and Hot-Stuff. The algorithm below borrows … Continue reading The BFT lens: Tendermint

The BFT lens: Hot-Stuff and Casper

This post is the first in a series discussing: Today I am going to overview a new algorithmic foundation called ‘Hot-Stuff the Linear, Optimal-Resilience, One-Message BFT Devil’ (in short, Hot-Stuff), developed jointly with my colleagues Ittai Abraham and Guy Gueta, and harness it to explain the safety and liveness of Casper the Friendly Finality Gadget. The key take-aways are: We have excellent … Continue reading The BFT lens: Hot-Stuff and Casper