Correctness and Fairness of Tendermint-core Blockchains.

摘要: Tendermint-core blockchains (e.g. Cosmos) are considered today one of the most viable alternatives for highly energy consuming proof-of-work such as Bitcoin and Ethereum. Their particularity is that they aim at offering strong consistency (no forks) in an open system combining two ingredients (i) a set validators generate blocks via variant Practical Byzantine Fault Tolerant (PBFT) consensus protocol (ii) selection strategy dynamically selects nodes to be next block proof-of-stake mechanism. However,the exact assumptions on model under which Tendermint underlying algorithms correct properties verifies have never been formally analyzed. The contribution this paper two-fold. First, while formalizing we precisely characterize problem solved by Tendermint. We prove eventual synchronous systems modified version solves additional assumptions, one-shot validation single repeated multiple blocks. These results hold even if hit failures, provided each instance less than third Byzantine. Our second relates fairness rewarding It common knowledge permisionless blockchain main threat tragedy commons may yield collapse mechanism not adequate. Ad minimum must fair, i.e.distributing rewards proportion merit participants. prove, first time systems, repeated-consensus based there exists (eventual) fair only synchronous. also show original however, modification makes it eventually fair.