streamlet

About this project

This project is currently being conducted at LASIGE (Faculty of Sciences of the University of Lisbon).

Currently, a normal implementation of Streamlet is being developed. The main goal of this work is to adapt the normal protocol to include trusted components. With this technique, the resilience of the protocol may increase by reducing the number of replicas from $3f + 1$ to $2f + 1$.

What is Streamlet?

Streamlet [1] is a novel streamlined blockchain protocol introduced by Benjamin Y. Chan and Elaine Shi. The authors present the protocol for three different settings: (a) Byzantine fault tolerant in a partially synchronous network, (b) Byzantine fault tolerant in a synchronous network, and (c) crash fault tolerant in a partially synchronous network. The model of interest is based on the first setting as its fault and timing assumptions have a broader spectrum than the two other settings, which is better suited for the ongoing work.

The protocol tolerates at most $f$ faults in a total of $3𝑓 + 1$ servers. It is assumed that servers have synchronized clocks, and the protocol advances in epochs that can have any defined duration. The whole protocol runs in a Propose-Vote fashion, where, in each epoch, the leader proposes a new block, and the replicas vote for the proposal.

Initializing the application

Dependencies

As of the moment, the only dependency used is the cryptography package for performing cryptographic operations. It can be installed using the command:

pip install -r requirements.txt

Execution

The application starts by executing a script (run_linux.sh or run_macos.sh depending on the OS). The script will spawn 4 terminal windows, each corresponding to a server. In this scenario, 1 Byzantine fault is being tolerated out of 4 servers. However, every spawned server is honest and does not deviate from the protocol.

Upon starting the application, it will create a folder called \blockchain where the finalized chain will be stored.

The application can be executed by running the following command:

Linux

./run_linux.sh

MacOS

./run_macos.sh

References

[1] Benjamin Y. Chan and Elaine Shi. 2020. Streamlet: Textbook Streamlined Blockchains. In Proceedings of the 2nd ACM Conference on Advances in Financial Technologies (New York, NY, USA) (AFT ’20). 1–11. https://doi.org/10.1145/3419614.3423256