Drand Bridge Pallet | Retroactive Funding

Introduction

Ideal Labs is working to develop onchain randomness solutions for substrate based chains and beyond. To date, we have participated in the web3 foundation’s grant program, where we developed a prototype version of a substrate-based randomness beacon. We are currently participants in the decentralized futures program. The work presented here is not covered within our contract with DF.

Verifiable randomness is a critical component for enabling fairness in decentralized protocols. Unfortunately, existing solutions for Substrate-based chains have limitations. We are proposing retroactive funding to support the development and maintenance of a Drand to Substrate bridge, bringing drand's verifiable randomness to Kusama.

We developed a drand bridge pallet, allowing Substrate-based runtimes to consume verifiable randomness from Drand's Quicknet. It can be used as a drop-in replacement anywhere the Randomness trait is used. We also built a node that supports host functions built with the arkworks-extensions library, which is required to efficiently verify drand's pulses. Finally, we developed a chain extension and smart contract environment so that the output of drand can be used within ink! smart contracts, along with a demonstration rock-paper-scissors game.

Key Benefits of this work include:

• Robust and Verifiable onchain randomness: drand enables highly secure, robust, verifiable randomness. With this work, it is easy to use it both within pallets and smart contracts.
• Timelock Encryption: drand's output enables us to build timelock encryption capabilities on top of the beacon, enabling new kinds of use cases for trustless protocols, such as trustless asset swaps, keyless crypto wallets, and more.
• Potential Ecocsystem Growth: EVM-based blockchains perform pairing operations poorly, so there is no cost-efficient drand > ETH bridge (though one does exist through Starknet). In general, EVM-based applications rely on VRF-based randomness-as-a-service solutions like Chainlink VRF, which carries a significant cost (also: no timelock encryption). This solution uses optimized arkworks extensions to efficiently compute pairings on-chain.

This post is to ask for feedback and review of our proposal for retroactive funding of our work on:

• a drand bridge pallet
• a node template supporting arkworks host functions
• a chain extension and contract environment for using randomness in ink! smart contracts
• A demo dapp: casino-style rock-paper-scissors

Retroactive funding will allow us to maintain and enhance this pallet, where we will work to support other beacons (e.g. NIST's beacon) and eliminate current limitations (see proposal). Our goal is for this to be an easy-to-use module for other networks - solochain or parachain - to acquire secure verifiable randomness and timelock encryption capabilities.

Read the full proposal here: https://docs.google.com/document/d/1wjn8Il3O5A51MU24CUdOhNyoU2YAABrLsWiOckM8Kg4/edit?usp=sharing