Albatross: An optimistic consensus algorithm
This addresses the problem of balancing speed and security in decentralized ledgers for blockchain developers and users, though it is incremental as it builds on existing BFT and PoS methods.
The paper tackles the challenge of achieving high performance without compromising transaction finality in blockchain consensus algorithms by introducing Albatross, a Proof-of-Stake speculative BFT algorithm that combines speculative performance with periodic finality guarantees, achieving performance close to the theoretical maximum for single-chain PoS consensus.
The consensus protocol is a critical component of distributed ledgers and blockchains. Achieving consensus over a decentralized network poses challenges to transaction finality and performance. Currently, the highest-performing consensus algorithms are speculative BFT algorithms, which, however, compromise on the transaction finality guarantees offered by their non-speculative counterparts. In this paper, we introduce Albatross, a Proof-of-Stake (PoS) blockchain consensus algorithm that aims to combine the best of both worlds. At its heart, Albatross is a high-performing, speculative BFT algorithm that offers strong probabilistic finality. We complement this by periodically guaranteeing finality through the Tendermint protocol. We prove our protocol to be secure under standard BFT assumptions and analyze its performance both on a theoretical and practical level. For that, we provide an open-source Rust implementation of Albatross. Our real-world measurements support that our protocol has a performance close to the theoretical maximum for single-chain Proof-of-Stake consensus algorithms.