SIMA Flutter Plugin #

A Flutter plugin that enables secure digital signature and authentication flows using the SIMA mobile application.

This package provides a clean and reusable interface for launching the SIMA app from Flutter, sending a cryptographic challenge, and receiving the signed response back into your application.

🔐 All SIMA-specific native logic is encapsulated inside the plugin.
🧼 The Flutter app layer stays clean and platform-agnostic.

🔗 Package Links #

• 📦 pub.dev: https://pub.dev/packages/sima
• 📄 License: MIT
• 🛠 Platforms: Android, iOS

✨ Features #

• Secure challenge–response signing flow
• Native SIMA app integration
• iOS and Android support
• Simple and minimal Flutter API
• Asset-based logo handling (path only)
• No Base64 handling required in Flutter
• Plugin-managed native callbacks
• Production-ready architecture

📦 Installation #

Add the package from pub.dev:

dependencies:
  sima: ^1.0.1

Then run:

flutter pub get

🎨 Asset Setup (Logo) #

The SIMA plugin requires a logo image to be displayed inside the SIMA application.

1️⃣ Add logo to your Flutter assets #

flutter:
  assets:
    - assets/logo.png

Supported formats:

• PNG
• JPG

⚠️ SVG is not supported for SIMA logos.

2️⃣ Pass only the asset path #

You do not need to convert the image to Base64.

logoPath: 'assets/logo.png'

The plugin will:

• load the asset natively
• convert it internally (Base64 on iOS, byte[] on Android)

🚀 Usage #

Basic Example #

import 'package:sima/sima.dart';

final response = await Sima.start(
  clientId: '<YOUR_CLIENT_ID>',
  clientMasterKey: '<YOUR_MASTER_KEY>',
  returnScheme: 'your-app-scheme',
  serviceName: 'Your App Name',
  logoPath: 'assets/logo.png',
);

🔁 Handling the Result #

if (response == null) {
  // Operation was cancelled or SIMA did not respond
} else if (!response.isSuccess) {
  // SIMA returned an error
  print(response.message);
} else {
  // Success
  print(response.signature);
  print(response.certificate);
}

📄 Response Model #

class SimaResponse {
  final String status;
  final String? signature;
  final String? certificate;
  final String? challenge;
  final String? requestId;
  final String? message;

  bool get isSuccess => status == 'success';
}

🧩 Platform Configuration #

🍎 iOS Setup #

1️⃣ URL Scheme

Add a custom URL scheme to your Info.plist:

<key>CFBundleURLTypes</key>
<array>
  <dict>
    <key>CFBundleURLSchemes</key>
    <array>
      <string>your-app-scheme</string>
    </array>
  </dict>
</array>

This scheme must match the returnScheme passed to Sima.start.

2️⃣ AppDelegate Callback Forwarding

The AppDelegate must forward the SIMA callback to the plugin:

override func application(
  _ app: UIApplication,
  open url: URL,
  options: [UIApplication.OpenURLOptionsKey : Any] = [:]
) -> Bool {

  guard let components = URLComponents(url: url, resolvingAgainstBaseURL: true),
        let items = components.queryItems else {
    return false
  }

  var data: [String: String] = [:]
  for item in items {
    data[item.name] = item.value ?? ""
  }

  NotificationCenter.default.post(
    name: NSNotification.Name("SIMA_CALLBACK"),
    object: nil,
    userInfo: data
  )

  return true
}

⚠️ Do not add any SIMA business logic here.

🤖 Android Setup #

1️⃣ Package Visibility (Android 11+)

Add the SIMA package to your AndroidManifest.xml:

<queries>
    <package android:name="az.dpc.sima" />
</queries>

2️⃣ MainActivity

No SIMA-related code is required.

class MainActivity : FlutterFragmentActivity()

The plugin handles all Android intents internally.

❗ Error Handling #

🔐 Security Notes #

• Never hardcode secrets in UI code
• Store clientMasterKey securely
• Always validate signatures server-side
• The plugin does not store sensitive data

🧠 Architecture Overview #

Flutter App
   |
   | MethodChannel
   v
SIMA Plugin
   |
   |-- iOS: URL Scheme + NotificationCenter
   |-- Android: Intent (implicit + explicit fallback)
   |
SIMA Mobile App

📄 License #

MIT License

⚠️ Disclaimer #

This plugin is not officially affiliated with SIMA.
Use it in accordance with SIMA platform policies and security requirements.