This paper introduces Slipstream, a Byzantine Fault Tolerance (BFT) protocol where nodes concurrently propose blocks to be added to a Directed Acyclic Graph (DAG) and aim to agree on block ordering. Slipstream offers two types of block orderings: an optimistic ordering, which is live and secure in a sleepy model under up to 50% Byzantine nodes, and a final ordering, which is a prefix of the optimistic ordering and ensures safety and liveness in an eventual lock-step synchronous model under up to 33% Byzantine nodes. Additionally, Slipstream integrates a payment system that allows for fast UTXO transaction confirmation independently of block ordering. Transactions are confirmed in three rounds during synchrony, and unconfirmed double spends are resolved in a novel way using the DAG structure.
@article{arxiv.2410.14876,
title = {Slipstream: Ebb-and-Flow Consensus on a DAG with Fast Confirmation for UTXO Transactions},
author = {Nikita Polyanskii and Sebastian Muller and Mayank Raikwar},
journal= {arXiv preprint arXiv:2410.14876},
year = {2025}
}