In addition to limiting the adversary via a communication model synchrony, asynchrony, or partial synchrony, we need a way to limit the adversary’s power to corrupt parties. Power tends to corrupt, and absolute power corrupts absolutely. – John Dalberg-Acton 1887 As John observed almost 150 years ago, if the adversary’s...| decentralizedthoughts.github.io
In this series of posts, we explore the marvelous world of consensus in the Asynchronous model. In this post, we start by simply defining the problem. Recall the FLP theorem: FLP theorem 1985: Any protocol where no two non-faulty parties decide different values in the asynchronous model that is resilient...| decentralizedthoughts.github.io
Many blockchain protocols work under partial synchrony. Examples include PBFT, SBFT, Cosmos (Tendermint), Diem (DiemBFT), Jolteon, Espresso Systems (HotStuff), Dfinity (Internet Computer Consensus) and Ethereum (Casper). In this post, we discuss key principles behind the design of partially synchronous blockchain protocols. These principles, in some form, apply to all of...| decentralizedthoughts.github.io
The prevailing view on fault-tolerant agreement is that it is impossible in asynchrony for deterministic protocols, but adding randomization solves the problem. This statement is confusing in two aspects: The FLP result says that any protocol, even a randomized protocol, must have a non-terminating execution where every configuration is bivalent...| decentralizedthoughts.github.io
