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Version: 0.2.0

Flutter SDK

In this section, you'll learn how to build a Flutter SDK using Mopro's native bindings. The process includes the following steps:

  1. Generate the binding using the Mopro CLI
  2. Integrate the binding into a Flutter Package
  3. How to install the Flutter SDK
  4. How to use the package
  5. How to run an example app

Generate the bindings using the Mopro CLI​

To get started with building Mopro bindings, refer to the Getting Started section. If you’d like to generate custom bindings for your own circuits or proving schemes, see the guide: Rust Setup for Android/iOS Bindings.

Then you will have a MoproAndroidBindings and/or MoproiOSBindings in the project directory.

Integrate the bindings into a Flutter Package​

  1. Clone the SDK template repository:
git clone https://github.com/zkmopro/mopro_flutter_package
  1. Replace the generated bindings:

  • iOS: Replace the bindings directory MoproiOSBindings with the generated files in the following location:

    • ios/MoproiOSBindings

  • Android: Replace the bindings directory MoproAndroidBindings/uniffi and MoproAndroidBindings/jniLibs with your generated files in the following location:

    • android/src/main/kotlin/uniffi
    • android/src/main/jniLibs
  1. Define the module API

How to install the Flutter SDK​

Add mopro_flutter_package to your project by manually editing pubspec.yaml.

dependencies:
    flutter:
        sdk: flutter

    mopro_flutter_package: # Or change to your own package name
        git:
            url: https://github.com/zkmopro/mopro_flutter_package # Or change to your own URL
info

If you need to update your keys, include your compiled Circom .zkey file as an asset. Add the asset path to your pubspec.yaml under the flutter: section:

flutter:
    uses-material-design: true # Ensure this is present
    assets:
        # Add the directory containing your .zkey file(s)
        - assets/circuits/
        # Or specify the file directly:
        # - assets/circuits/multiplier2_final.zkey

Make sure the path points correctly to where you've placed your .zkey file within your Flutter project.

Run the following command in your terminal from the root of your Flutter project:

flutter pub get

How to use the package​

Here is an example of how to integrate and use this package

// Import the package
import 'package:mopro_flutter_package/mopro_flutter_package.dart';
import 'package:mopro_flutter_package/mopro_flutter_types.dart';

final MoproFlutterPackage _mopro = MoproFlutterPackage();
const int a = 3;
const int b = 5;
final Map<String, List<String>> inputs = {
    'a': [a.toString()],
    'b': [b.toString()],
};
// Convert inputs to JSON string
final String inputsJson = jsonEncode(inputs);

final GenerateProofResult proofResult = await _mopro.generateProof(
    zkeyPath: zkeyAssetName, // Use the zkey asset path provided in pubspec.yaml (e.g. "assets/multiplier2_final.zkey")
    inputs: inputsJson,
);

final bool isValid = await _mopro.verifyProof(
    zkeyPath: zkeyAssetName, // Use the same zkey asset path
    proof: proofResult.proof, // Use the generated proof
    inputs: proofResult.inputs, // Use the public inputs from proof generation
);

How to run an example app​

  • Open the example app that uses the defined flutter package in the example/ folder 
    cd example
  • Install the dependencies 
    flutter pub get
  • Open an iOS simulator/device or an Android emulator/device and run the example app 
    flutter run
  • Clean the cache if you update the bindings and it throws errors 
    flutter clean