[TOC]

Under Development ...

Quick start

• First, clone the code from Github. (with --recurse)

git clone --recurse https://github.com/PlatONnetwork/proof_of_custody.git

• Next, install some dependencies by executing the following script.

sudo bash ./pre_install.sh

• Next, compile mcl/mpir/SimpleOT.

./pre_compile.sh

• Next, compile this project.

./compile.sh

• Now, run the test.

./test.sh [<parties> [<host>]]

parties: the number of parties. default 2. host: the host or ip of the party 0. default localhost.

[OLD,TODO]

Introduction

This project implements the proof of custody algorithm in Ethereum 2.0 with secure multi-party computation.

Custody game is a mechnism will be adpoted in Ethereum 2.0 (Phase 1) to solve the data availability problem. It is designed to be mpc-friendly, since the mpc implementation will avoid single point of failure, reduce the staking cost and enable the possibility of trustless validator pools, et al.

This project aims to estimate the feasiblity and performance of the mpc implementation of proof of custody. The implementation is built on and highly customized from SCALE-MAMBA with optimizations specific to proof of custody.

The project is officially granted by Ethereum Foundation.

Dependencies

• openssl
• gmp
• mpir
• mcl
• yasm

Run the following script to install all the dependencies.

sudo ./install_deps.sh

Compile

Run the following command to compile.

./compile.sh

Init

Run the following command to initiate the system.

./init.sh n t

• n : the number of parties.

• t : the number of threshold, and 0 < t < n/2

• Shamir type of LSSS is used.

• The default modulus (under BLS12-381 curve) is

4002409555221667393417789825735904156556882819939007885332058136124031650490837864442687629129015664037894272559787

Run the demo

You could run the demo in localhost, with the following command. Note: init should be run first.

./run.sh n

• run once of the protocol.
• n : the number of parties, should be the same as the one in init.

./runbatch.sh n

• run 50 times (default) of the protocol.
• n : the number of parties, should be the same as the one in init.

Progresses

Stage I

1. Remove the compiler part of SCALE-MAMBA (100%)
2. DKG of BLS (100%)
3. Distributed sign of BLS (100%)
4. Universal hash function (UHF) (100%)
5. Legendre PRF (100%)

Performance

1. the total time for 3-1 case is less than 0.5s in LAN.

Acknowledgements

• Special thanks to Dankrad Feist for introducing proof of custody and deep discussions of the technique details.

• Thanks to Nigel Smart for discussions of PRSS implementation in SCALE-MAMBA.

• Thanks to Yu Yu for discussions of universal hash function and the security of Legendre PRF.

Contact

xiang.xie@platon.network