Handel

Handel is a fast multi-signature aggregation protocol for large Byzantine committees. This is the reference implementation in Go.

The protocol

Handel is a Byzantine fault tolerant aggregation protocol that allows for the quick aggregation of cryptographic signatures over a WAN. Handel has both logarithmic time and network complexity and needs minimal computing resources. For more information about the protocol, we refer you to the following presentations:

• Stanford Blockchain Conference 2019: the slides presented.
• Community Ethereum Development Conference 2019: the slides

We have a paper in submission available here: https://arxiv.org/abs/1906.05132 Please note that the slides are not up-to-date with the latest version of the paper.

The reference implementation

Handel is an open-source Go library implementing the protocol. It includes many openness points to allow plugging different signature schemes or even other forms of aggregation besides signature aggregation. We implemented extensions to use Handel with BLS multi-signatures using the BN256 curve. We ran large-scale tests and evaluated Handel on 2000 AWS nano instances located in 10 AWS regions and running two Handel nodes per instance. Our results show that Handel scales logarithmically with the number of nodes both in communication and re- source consumption. Handel aggregates 4000 BN256 signatures with an average of 900ms completion time and an average of 56KBytes network consumption.

Installation

This library requires go version 1.11+

This library uses go modules, so make sure either you clone this library outside your $GOPATH or use GO111MODULE=on before building it.

If you want to hack around the library, you can find more information about the internal structure of Handel in the HACKING.md file.

License

The library is licensed with an Apache 2.0 license. See LICENSE for more information.