pkb_screen_guard #

pkb_screen_guard is a Flutter plugin that helps protect sensitive screens from:

• Screenshots & recent-app previews
• Screen recording
• Screen mirroring / casting (external displays)
• Remote-control tools (heuristic)
• Rooted / jailbroken devices (heuristic)

It is designed for high-security applications such as:

• Banking / fintech apps
• Cooperative / credit union apps
• Enterprise / internal business apps
• Any app that must pass security / penetration testing

Supports Android and iOS.

✨ Features #

📦 Installation #

Add to your pubspec.yaml:

dependencies:
  pkb_screen_guard: ^0.0.1

Then:

flutter pub get

🚀 Quick Start #

Initialize in main.dart #

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  await PkbScreenGuard.enableSecure();  // Android only
  await PkbScreenGuard.startMonitoring();

  runApp(const MyApp());
}

📡 Listen to security events #

PkbScreenGuard.events().listen((event) {
  debugPrint('pkb_screen_guard event: $event');
});

Possible events:

{
  "event": "screenCaptured"
}
{
  "event": "screenCapturingStopped"
}
{
  "event": "externalDisplayAttached"
}
{
  "event": "externalDisplayDetached"
}
{
  "event": "remoteAppDetected",
  "package": "com.teamviewer.teamviewer.market.mobile"
}
{
  "event": "rootDetected",
  "score": 10
}
{
  "event": "hookDetected"
}

🛡 Root / Jailbreak check #

final rooted = await PkbScreenGuard.checkRooted();

📘 Full Example #

import 'dart:async';
import 'package:flutter/material.dart';
import 'package:pkb_screen_guard/pkb_screen_guard.dart';

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  runApp(const DemoApp());
}

class DemoApp extends StatelessWidget {
  const DemoApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'pkb_screen_guard Demo',
      theme: ThemeData(useMaterial3: true),
      home: const GuardHomePage(),
    );
  }
}

class GuardHomePage extends StatefulWidget {
  const GuardHomePage({super.key});

  @override
  State<GuardHomePage> createState() => _GuardHomePageState();
}

class _GuardHomePageState extends State<GuardHomePage> {
  bool? _rooted;
  final List<Map<String, dynamic>> _events = [];
  StreamSubscription<Map<String, dynamic>>? _sub;

  @override
  void initState() {
    super.initState();
    _initGuard();
  }

  Future<void> _initGuard() async {
    final rooted = await PkbScreenGuard.checkRooted();
    setState(() {
      _rooted = rooted;
    });

    _sub ??= PkbScreenGuard.events().listen((event) {
      setState(() {
        _events.insert(0, {
          'ts': DateTime.now().toIso8601String(),
          ...event,
        });
      });
    });

    await PkbScreenGuard.enableSecure();
    await PkbScreenGuard.startMonitoring();
  }

  @override
  void dispose() {
    _sub?.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final rootedText = _rooted == null
        ? 'Checking device security...'
        : (_rooted == true
            ? 'Root / Jailbreak detected'
            : 'No root / jailbreak detected');

    return Scaffold(
      appBar: AppBar(
        title: const Text('pkb_screen_guard Example'),
      ),
      body: ListView(
        padding: const EdgeInsets.all(16),
        children: [
          Text('Device status: $rootedText'),
          const Divider(),
          const Text('Recent events:'),
          ..._events.map(_eventTile),
        ],
      ),
    );
  }

  Widget _eventTile(Map<String, dynamic> e) {
    return Card(
      child: ListTile(
        title: Text('${e["event"]}'),
        subtitle: Text('${e["ts"]}'),
      ),
    );
  }
}

🧱 Architecture Overview #

Android #

• Uses FLAG_SECURE
• Root detection (test-keys, su paths)
• Hook detection (Frida/Xposed heuristics)
• Remote-control app detection via package scan
• External display detection
• Black overlay using a fullscreen view

iOS #

• Detects screen recording via isCaptured
• External display detection via UIScreen notifications
• Jailbreak heuristic detection
• Black overlay using a top-level UIWindow

⚠️ Disclaimer #

This plugin improves app security but cannot guarantee absolute protection. Use it as a defense-in-depth layer along with backend validation.

📄 License #

MIT (or your chosen license)