RISC Zero Foundry Template

Note: This software is not production ready. Do not use in production.

Note: This template was recently updated to work without the relay. If you'd like the relay version, head over to the relay branch

Starter template for writing an application using RISC Zero and Ethereum.

This repository implements an application on Ethereum utilizing RISC Zero as a coprocessor to the smart contract application. It provides a starting point for building powerful new applications on Ethereum that offload computationally intensive (i.e. gas expensive), or would be difficult to implement Solidity (e.g. ed25519 signature verification, or HTML parsing).

Prove computation with the RISC Zero zkVM and verify the results in your Ethereum contract.

Overview

Here is a simplified overview of how devs can integrate RISC Zero, with Bonsai proving, into their Ethereum smart contracts:

1. Run your application logic in the RISC Zero zkVM. The provided publisher app sends an off-chain proof request to the Bonsai proving service.
2. Bonsai generates the program result, written to the journal, and a SNARK proof of its correctness.
3. The publisher app submits this proof and journal on-chain to your app contract for validation.
4. Your app contract calls the RISC Zero Verifier to validate the proof. If the verification is successful, the journal is deemed trustworthy and can be safely used.

Dependencies

First, install Rust and Foundry, and then restart your terminal.

# Install Rust
curl https://sh.rustup.rs -sSf | sh
# Install Foundry
curl -L https://foundry.paradigm.xyz | bash

Next, you will need to install the cargo risczero tool. We'll use cargo binstall to get cargo-risczero installed, and then install the risc0 toolchain. See RISC Zero installation for more details.

cargo install cargo-binstall
cargo binstall cargo-risczero
cargo risczero install

Now you have all the tools you need to develop and deploy an application with RISC Zero.

Quick Start

First, install the RISC Zero toolchain using the instructions above.

Now, you can initialize a new RISC Zero project at a location of your choosing:

forge init -t risc0/bonsai-foundry-template ./my-project

Congratulations! You've just started your first RISC Zero project.

Your new project consists of:

• a zkVM program (written in Rust), which specifies a computation that will be proven;
• a app contract (written in Solidity), which uses the proven results;
• a publisher which makes proving requests to Bonsai and posts the proof to Ethereum. We provide an example implementation, but your dApp interface or application servers could act as the publisher.

Build the Code

• Builds for zkVM program, the publisher app, and any other Rust code.

  cargo build

• Build your Solidity smart contracts

  NOTE: cargo build needs to run first to generate the ImageID.sol contract.

  forge build

Run the Tests

• Tests your zkVM program.

  cargo test

• Test your Solidity contracts, integrated with your zkVM program.

  RISC0_DEV_MODE=true forge test -vvv 

Develop Your Application

To build your application, you'll need to make changes in three folders:

• write the code you want proven in the methods/guest folder.
• write the on-chain part of your project in the contracts folder.
• adjust the publisher example in the apps folder.

Configuring Bonsai

Note: To request an API key complete the form here.

With the Bonsai proving service, you can produce a Groth16 SNARK proof that is verifiable on-chain. You can get started by setting the following environment variables with your API key and associated URL.

export BONSAI_API_KEY="YOUR_API_KEY" # see form linked above
export BONSAI_API_URL="BONSAI_URL" # provided with your api key

Now if you run forge test with RISC0_DEV_MODE=false, the test will run as before, but will additionally use the fully verifying RiscZeroGroth16Verifier contract instead of MockRiscZeroVerifier and will request a SNARK receipt from Bonsai.

RISC0_DEV_MODE=false forge test -vvv

Deterministic Builds

By setting the environment variable RISC0_USE_DOCKER a containerized build process via Docker will ensure that all builds of your guest code, regardless of the machine or local environment, will produce the same image ID. The image ID, and its importance to security, is explained in more detail in our developer FAQ.

RISC0_USE_DOCKER=1 cargo build

Note: This requires having Docker installed and in your PATH. To install Docker see Get Docker.

Deploy Your Application

When you're ready, follow the deployment guide to get your application running on Sepolia.

Project Structure

Below are the primary files in the project directory

.
├── Cargo.toml                      // Configuration for Cargo and Rust
├── foundry.toml                    // Configuration for Foundry
├── apps
│   ├── Cargo.toml
│   └── src
│       └── lib.rs                  // Utility functions
│       └── bin                     
│           └── publisher.rs        // Example app to publish program results into your app contract 
├── contracts
│   ├── CollatzNumber.sol           // Basic example contract that stores the largest number provably shown to satisfy the Collatz conjecture
│   └── ImageID.sol                 // Generated contract with the image ID for your zkVM program
├── methods
│   ├── Cargo.toml
│   ├── guest
│   │   ├── Cargo.toml
│   │   └── src
│   │       └── bin                 // You can add additionally guest prgrams to this folder
│   │           └── collatz.rs      // Example guest program for cheking if a number satisfies the Collatz conjecture
│   └── src
│       └── lib.rs                  // Compiled image IDs and tests for your guest programs
└── tests
    ├── CollatzNumber.t.sol            // Tests for the basic example contract
    └── Elf.sol                     // Generated contract with paths the guest program ELF files.