Zcash Foundation FROST Demos
This repository contains a set of command line demos that uses the ZF FROST libraries and reference implementation. Their purpose is to:
- identify gaps in our documentation
- provide usage examples for developer facing documentation
- provide reference implementations for developers wanting to use FROST in a “real world” scenario.
About FROST (Flexible Round-Optimised Schnorr Threshold signatures)
Unlike signatures in a single-party setting, threshold signatures require cooperation among a threshold number of signers, each holding a share of a common private key. The security of threshold schemes in general assume that an adversary can corrupt strictly fewer than a threshold number of participants.
Two-Round Threshold Schnorr Signatures with FROST presents a variant of a Flexible Round-Optimized Schnorr Threshold (FROST) signature scheme originally defined in FROST20. FROST reduces network overhead during threshold signing operations while employing a novel technique to protect against forgery attacks applicable to prior Schnorr-based threshold signature constructions. This variant of FROST requires two rounds to compute a signature, and implements signing efficiency improvements described by Schnorr21. Single-round signing with FROST is not implemented here.
This repo contains 4 projects:
Trusted Dealer demo - WIP DKG demo - WIP Coordinator demo - WIP Participant demo - WIP
NOTE: This is for demo purposes only and should not be used in production.
You will need to have Rust and Cargo installed.
- Clone the repo. Run
git clone https://github.com/ZcashFoundation/frost-zcash-demo.git
and in separate terminals:
cargo run --bin trusted-dealer or
cargo run --bin dkg
cargo run --bin coordinator
cargo run --bin participants. Do this in separate terminals for separate participants.
The demos support two communication mechanisms. By using the
--cli flag, they
will print JSON objects to the terminal, and participants will need to copy &
paste objects and send them amongst themselves to complete the protocol.
--cli flag, the demos will use socket communications. The
coordinator will act as the server and the participants will be clients. See
Socket communication example
Create 3 key shares with threshold 2 using trusted dealer:
cargo run --bin trusted-dealer -- -t 2 -n 3
The key packages will be written to files. Securely send the partipant's key packages to them (or just proceed if you are running everything locally for testing).
Start a signing run as the coordinator:
cargo run --bin coordinator -- -i 0.0.0.0 -p 2744 -n 2 -m message.raw -s sig.raw
This will start a server listening for connections to any IP using port 2744.
(These are the default values so feel free to omit them.) The protocol will run
with 2 participants, signing the message inside
message.raw (replace as
appropriate). The signature will be written to
sig.raw. The program will keep
running while it waits for the participants to connect to it.
Each participant should then run (or run in different terminals if you're testing locally):
cargo run --bin participant -- -i 127.0.0.1 -p 2744 -k key-package-1.json
It will connect to the Coordinator using the given IP and port (replace as needed), using the specified key package (again replace as needed).
Once two participants are running, the Coordinator should complete the protocol and write the signature to specified file.
Currently the demo supports curve Ed25519 and RedPallas. To use RedPallas, pass
--feature redpallas to all commands. When it's enabled, it will automatically
switch to Rerandomized FROST and it can be used to sign Zcash transactions.