Ebb-and-Flow Protocols: A Resolution of the Availability-Finality Dilemma

Paper: Ebb-and-Flow Protocols: A Resolution of the Availability-Finality Dilemma. Joachim Neu, Ertem Nusret Tas, and David Tse. 2020

This paper presents a flexible SMR protocol allowing clients to choose between availability (liveness) and finalization (safety).
Informally,
- If less than \(33\%\) nodes are Byzantine, the log is safe and live.
- If less than \(50\%\) nodes are Byzantine, the log is safe.
This paper achieves flexibility via composition of a sync and partially synchronous protocol.
- Construction: Permissioned longest chain -> Partially Synchronous Streamlet.

References

Joachim Neu, Ertem Nusret Tas, and David Tse. 2020. “Ebb-and-Flow Protocols: A Resolution of the Availability-Finality Dilemma.” https://eprint.iacr.org/2020/1091.