Secure QR Generator

A Flutter package for generating secure, auto-regenerating QR codes with encryption, digital signatures, and automatic expiration management.

Features

  • 🔒 Secure by Design: Support for AES encryption and HMAC-SHA256 signatures
  • ⏱️ Auto-Expiration: Built-in validity duration management
  • 🔄 Auto-Regeneration: Automatic QR code refresh before expiration
  • 📱 Flutter Integration: Ready-to-use Flutter widget
  • 🎨 Customizable Styling: Full control over QR code appearance
  • ⚡ Performance Optimized: Efficient regeneration with minimal overhead

Installation

Add this to your package's pubspec.yaml file:

dependencies:
  secure_qr_generator: ^1.0.4

Then run:

flutter pub get

Quick Start

Basic Usage

import 'package:secure_qr_generator/secure_qr_generator.dart';

// Create a configuration
final config = GeneratorConfig.production(
  secretKey: 'your-32-character-secret-key-here!!!',
  validityDuration: Duration(minutes: 5),
);

// Initialize the generator
final generator = SecureQRGenerator(config);

// Create QR data
final data = QRData(
  payload: {'userId': '123', 'access': 'granted'},
  metadata: {'purpose': 'access_control'},
  tags: ['entrance', 'visitor'],
);

// Generate a QR code
final result = await generator.generateQR(data);

Using the Auto-Regenerating Widget

AutoRegeneratingQRView(
  data: data,
  generator: generator,
  size: 200,
  style: QrStyle(
    eyeStyle: QrEyeStyle(eyeShape: QrEyeShape.square),
    dataModuleStyle: QrDataModuleStyle(
      dataModuleShape: QrDataModuleShape.circle,
    ),
  ),
  onRegenerate: (result) {
    print('New QR generated: ${result.id}');
  },
  onError: (error) {
    print('Error: $error');
  },
)

Configuration Options

Development Configuration

final devConfig = GeneratorConfig.development();

Production Configuration

final prodConfig = GeneratorConfig.production(
  secretKey: 'your-secure-production-key-here!!!!!!',
  validityDuration: Duration(minutes: 5),
);

Custom Configuration

final customConfig = GeneratorConfig(
  secretKey: 'your-secret-key',
  validityDuration: Duration(minutes: 10),
  enableEncryption: true,
  enableSignature: true,
  dataVersion: 1,
  idPrefix: 'CUSTOM_',
);

Advanced Features

Custom QR Code Styling

QrStyle(
  eyeStyle: QrEyeStyle(
    eyeShape: QrEyeShape.square,
    color: Colors.blue,
  ),
  dataModuleStyle: QrDataModuleStyle(
    dataModuleShape: QrDataModuleShape.circle,
    color: Colors.black,
  ),
  embeddedImage: AssetImage('assets/logo.png'),
  embeddedImageStyle: QrEmbeddedImageStyle(
    size: Size(40, 40),
  ),
)

Custom Regeneration Interval

AutoRegeneratingQRView(
  data: data,
  generator: generator,
  regenerationInterval: Duration(minutes: 2),
  // ... other parameters
)

Custom QR Code Builder

AutoRegeneratingQRView(
  data: data,
  generator: generator,
  builder: (qrData) => Container(
    decoration: BoxDecoration(
      border: Border.all(color: Colors.blue),
    ),
    child: QrImageView(
      data: qrData,
      size: 200,
    ),
  ),
)

Error Handling

The package includes comprehensive error handling:

try {
  final result = await generator.generateQR(data);
  // Use the result
} on GenerationError catch (e) {
  switch (e.type) {
    case GenerationErrorType.configuration:
      print('Configuration error: ${e.message}');
      break;
    case GenerationErrorType.encryption:
      print('Encryption error: ${e.message}');
      break;
    case GenerationErrorType.payloadTooLarge:
      print('Payload too large: ${e.message}');
      break;
    // Handle other error types...
  }
}

Security Considerations

  • Keep your secretKey secure and never commit it to version control
  • Use different keys for development and production environments
  • Consider the QR code size limits when adding data
  • Choose an appropriate validity duration for your use case
  • Regularly rotate encryption keys in production

Contributing

Contributions are welcome! Please read our contributing guidelines before submitting pull requests.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Libraries

secure_qr_generator