Revisiting Tendermint: Design Tradeoffs, Accountability, and Practical Use

Tendermint is a deterministic consensus protocol and is one of the most mature implementations of its kind. This implementation is used as the core for building State Machine Replication (SMR) platforms with Byzantine fault-tolerant (BFT) guarantees. A noteworthy deployment of Tendermint has been in continuous operation since 2019 within a blockchain called Cosmos Hub. The Cosmos Hub supports the development of decentralized applications, and stands as one of the largest and most stable ongoing deployments of a BFT SMR platform.While successful in practice, the Tendermint consensus protocol has no definitive description in the literature. It is not clear what makes this protocol unique or how it fits into a blockchain protocol stack. In this short paper, we revisit Tendermint. We contrast Tendermint with other major consensus algorithms, examining its unique design choices. We also focus on the requirements which dictated Tendermint’s design. Lastly, we briefly analyze the accountability support which Tendermint provides.