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

This repository contains the source code for the simulations of ebb-and-flow protocols presented in [Ebb-and-Flow]. For the source code of the attack presented in [Ebb-and-Flow] on the Gasper consensus protocol, please see: https://github.com/tse-group/gasper-attack

Simulation of Snap-and-Chat Protocol

We simulate a snap-and-chat protocol constructed with Sleepy and Streamlet as constituent protocols, in the four scenarios described in [Ebb-and-Flow]:

• Figure 2: Overview in the introduction. Code: 006-simulation-04-overview-01.jl. Results: sim-04.dat, sim-04-phases.dat.
• Figure 9: Dynamic participation. Code: 004-simulation-03-dynamic-participation-01.jl. Results: sim-03.dat.
• Figure 10: Intermittent network partitions. Code: 003-simulation-01-network-partitions-01.jl. Results: sim-01.dat, sim-01-phase*.dat.
• Figure 11: Convergence after network partition and/or low participation. Code: 005-simulation-02-convergence-01.jl. Results: sim-02.dat, sim-02-phases.dat.

The simulation is implemented in the Julia programming language. The simulation code is structured as follows:

• The main .jl file corresponding to the respective scenario contains the parameters of the scenario as well as the overall logic simulating the communication between participants, network partitions, dynamic participation, etc.
• Basics.jl: Contains some constants as well as generic operations on blocks and blockchains.
• ProtocolDA.jl: Implementation of Sleepy.
• ProtocolP.jl: Implementation of Streamlet.
• Validators.jl: Composition of Sleepy and Streamlet, as well as adversarial validator behavior.

To reproduce the Julia runtime environment (for Julia version 1.4.0), consult Manifest.toml and Project.toml.

References

• [Ebb-and-Flow]
  Ebb-and-Flow Protocols: A Resolution of the Availability-Finality Dilemma
  Joachim Neu, Ertem Nusret Tas, David Tse
  arXiv:2009.04987