Circom React Native

CircomReactNative is a React Native package for generating and verifying Circom zero-knowledge proofs using the groth16 backend.

The Swift and Android bindings are generated by the mopro CLI using the Circom adapter, which utilizes circom-prover with circom-witnesscalc for witness generation and arkworks for groth16 proof construction.

To learn more about the original Rust implementation before generating bindings, please refer to zkmopro documentation.

Note

To use circom-witnesscalc, follow the README instructions to generate the graph file from your Circom circuits. Or the script from semaphore-rs

How to Import the Package

Use a Node.js package manager in your React Native app to install dependencies. For example:

# npm
npm install https://github.com/zkmopro/CircomReactNative
# yarn / pnpm
yarn add https://github.com/zkmopro/CircomReactNative

Alternatively, you can manually add it to your package.json:

"dependencies": {
 "circom-react-native": "github:zkmopro/CircomReactNative",
}

How to Use the Package

Here is an example of how to integrate and use this package.
For the full test implementation, see example/App.tsx.

Import the package

import CircomReactNative, {
  CircomProofLib,
  CircomProofResult,
  ProofLibOption,
} from "circom-react-native";

Load graph and zkey

Please checkout circom and circom-witensscalc to see how to generate the zkey and the graph.

To load the circuit and graph in an Expo app, please checkout e.g. zkeyFilePath to get the path. Then define the file path, e.g.

circomProve

const circuitInputs = {
    a: [a],
    b: [b],
};

// Generate proof
const res: CircomProofResult =
    await CircomReactNative.circomProve(
        graphFilePath.replace("file://", ""),
        JSON.stringify(circuitInputs),
        zkeyFilePath.replace("file://", ""),
);

verifyCircomProof

// Verify proof
const proofLib: CircomProofLib = {
    proofLib: ProofLibOption.Arkworks,
};
const isValid: boolean = await Circom.verifyCircomProof(
        zkeyFilePath.replace("file://", ""),
        res,
        proofLib,
);

console.log("Proof verification result:", isValid);

Warning

The default bindings are built specifically for the multiplier2 circom circuit. If you'd like to update the circuit or switch to a different proving scheme, please refer to the How to Build the Package section.
Circuit source code: https://github.com/zkmopro/circuit-registry/tree/main/multiplier2
Example .zkey file for the circuit: http://ci-keys.zkmopro.org/multiplier2_final.zkey
Example graph file for the circuit: https://github.com/zkmopro/mopro/raw/refs/heads/main/circom-prover/test-vectors/multiplier2.bin

Test the package

Use the example app folder:

cd example

1. Install the dependencies

npm install

2. Start the server

npm run start

3. Run the app on iOS

npm run ios

4. Run the app on Android

export ANDROID_HOME=~/Library/Android/sdk/

npm run android

Warning

If you are using Expo, run the app with:

"ios": "expo run:ios",
"android": "expo run:android"

These commands build and run the native iOS and Android projects.
And make sure the Android minSdkVersion is set to 28.

Troubleshooting

If you see errors like this:

Unable to resolve "./assets/keys/multiplier2_final.zkey" from "app/(tabs)/index.tsx"

To make .zkey and .bin files accessible as assets, update metro.config.js like this:

config.resolver.assetExts.push('zkey');
config.resolver.assetExts.push('bin');

Community

• X account:
• Telegram group:

Acknowledgements

This work was initially sponsored by a joint grant from PSE and 0xPARC. It is currently incubated by PSE.

This project is heavily inspired by ezkl-swift-package and follows a similar approach for integrating native cryptographic libraries into Swift via a Swift Package.