Noir React Native starter

Description

This is a simple React Native app showcasing how to use Noir in a mobile app (both for iOS and Android) to generate and verify proofs directly on mobile phones.

Mobile proving

iOS

The app integrates with the Swoir library to generate proofs with Noir on iOS. The library is written in Swift and is available as a Swift Package.

Android

The app integrates some Kotlin code following a similar logic to Swoir, by taking the same type of inputs and the circuit manifest to generate proofs with Noir on Android. This part of the code will be exported soon in a separate library to simplify reusability.

General setup

If you are unfamiliar with React Native, you can follow the official guide to set up your environment.

For the rest follow the steps below:

1. Clone the repository
2. Run npm install to install the dependencies

Setup on iOS

1. Run npx pod-install to install the pods for the iOS project
2. Open the project in Xcode
3. Make sure you see the Swoir, SwoirCore and Swoirenberg libraries in the Package Dependencies (if not please open an issue)
4. Make sure you have a valid provisioning profile set up for the app in Signing & Capabilities
5. Build & Run the app on your device

Setup on Android

1. Make sure to define the environment varialbes ANDROID_HOME, NDK_VERSION and HOST_TAG, they will help the build process to find Android NDK necessary to compile the native code. Example on MacOS:

export ANDROID_HOME=$HOME/Library/Android/sdk
export NDK_VERSION=26.3.11579264
export HOST_TAG=darwin-x86_64

2. Connect your Android device and check it is connected by running npm run android-devices. It should displayed the connected device as device in the list of devices attached.
3. Run npm run android to build and run the app on your device

Note: If you want to do a clean build, you can run ./scripts/clean-android.sh before running npm run android

How to replace the circuit

This app comes with a basic Noir circuit checking that the prover knows two private inputs a and b such that the public input result is equal to their product a * b, a circuit verifying a secp256r1 signature and one doing multiple rounds of pedersen hashing. You can replace any of these circuits with your own by following these steps:

1. Go into the circuits folder
2. Create a new folder for your circuit such as my_circuit
3. Create a Nargo.toml file in this folder following the structure of the Nargo.toml file in the other subfolders of the circuits folder. Don't forget to change the name of the circuit in the name field
4. Create a src folder and create a main.nr file in it
5. Make sure you have the version 0.30.0 of nargo. You can check by running nargo --version. If you have a different version, you can use noirup -v 0.30.0. And if you don't have noirup follow the instructions here.
6. Write your Noir code in main.nr and run nargo check to generate the Prover.toml and Verifier.toml files
7. Run nargo compile to compile the circuit
8. It will generate a new <your_circuit_name>.json file in /target
9. You can then replace the import in the Javascript code to load this circuit instead

Note on performance

Bear in mind that mobile phones have a limited amount of available RAM. The circuit used in this app is really simple so the memory usage is not a problem. However, if you plan to use more complex circuits, you should be aware that the memory usage will increase and may go above the available memory on the device causing the proof generation to fail.

Noir version currently supported

The current version of Noir supported by the app is 0.30.0