What Is biometric_iot_bridge?

biometric_iot_bridge is a Flutter plugin that bridges three distinct systems into one lightweight API:

It depends on three well-maintained packages: local_auth for biometrics, mqtt_client for MQTT, and crypto for token hashing.

Why Build biometric_iot_bridge?

Most Flutter IoT packages focus on communication — not trust. Anyone can publish to an MQTT topic. biometric_iot_bridge adds a hardware-level trust gate.

Consider a smart lock app: without biometric gating, any valid session can trigger the unlock. With biometric_iot_bridge, the device only unlocks when the enrolled user physically authenticates.

How to Install biometric_iot_bridge

Step 1 — Add to pubspec.yaml

# pubspec.yaml
dependencies:
  biometric_iot_bridge: ^0.1.1

flutter pub get

Step 2 — Android Setup

Add to android/app/src/main/AndroidManifest.xml:

<uses-permission android:name="android.permission.USE_BIOMETRIC"/>
<uses-permission android:name="android.permission.USE_FINGERPRINT"/>

Step 3 — iOS Setup

Add to ios/Runner/Info.plist:

<key>NSFaceIDUsageDescription</key>
<string>This app uses Face ID / Touch ID to verify your identity.</string>

Quick Start: Biometric + MQTT in 5 Lines

import 'package:biometric_iot_bridge/biometric_iot_bridge.dart';

final bridge = BiometricIotBridge();

// 1. Verify biometrically
final authenticated = await bridge.verifyBiometrics();
if (!authenticated) return;

// 2. Generate secure token
final token = bridge.generateSecureToken("your_secret_key");

// 3. Signal IoT device via MQTT
await bridge.sendRemoteSignal("iot/door/unlock", token);

Complete Flutter Widget Example

import 'package:flutter/material.dart';
import 'package:biometric_iot_bridge/biometric_iot_bridge.dart';

class SecureUnlockPage extends StatefulWidget {
  @override
  _SecureUnlockPageState createState() => _SecureUnlockPageState();
}

class _SecureUnlockPageState extends State<SecureUnlockPage> {
  final bridge = BiometricIotBridge();
  String _status = "Ready";

  Future<void> _triggerUnlock() async {
    setState(() => _status = "Verifying biometrics...");
    final ok = await bridge.verifyBiometrics();
    if (!ok) { setState(() => _status = "Auth failed."); return; }
    final token = bridge.generateSecureToken("secret_key");
    await bridge.sendRemoteSignal("iot/door/unlock", token);
    setState(() => _status = "✅ Unlocked!");
  }

  @override
  Widget build(BuildContext context) => Scaffold(
    appBar: AppBar(title: Text("Biometric IoT Unlock")),
    body: Center(child: Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: [
        Text(_status, style: TextStyle(fontSize: 18)),
        SizedBox(height: 24),
        ElevatedButton.icon(
          icon: Icon(Icons.fingerprint),
          label: Text("Authenticate & Unlock"),
          onPressed: _triggerUnlock,
        ),
      ],
    )),
  );
}

API Reference

verifyBiometrics()

Triggers the platform's native biometric dialog using local_auth. Returns true on success. No biometric data is stored or transmitted.

Future<bool> verifyBiometrics()

generateSecureToken(String secret)

Generates a cryptographically secure token using the crypto package. Returns a hex-encoded SHA hash. Never expose the secret key client-side in production without server-side validation.

String generateSecureToken(String secret)

sendRemoteSignal(String topic, String token)

Publishes the token to an MQTT broker using mqtt_client. Works with Mosquitto, HiveMQ, AWS IoT Core, Azure IoT Hub, and EMQX.

Future<void> sendRemoteSignal(String topic, String token)

Supported Platforms

Real-World Use Cases for biometric_iot_bridge

This package is purpose-built for scenarios where identity must be hardware-verified before a device action occurs:

• Smart door locks — biometric auth required before MQTT unlock command
• Industrial equipment — prevent unauthorized operation with hardware-level gating
• Home automation — biometric-controlled lighting, HVAC, and security systems
• Healthcare device control — verify clinician identity before adjusting connected equipment
• Multi-factor architectures — combine with server-side validation for layered security
• Vehicle access systems — biometric-triggered MQTT commands for connected vehicles

Security Design Philosophy

biometric_iot_bridge follows a non-invasive, privacy-first security model:

• All biometric verification via platform-native APIs — the app never sees raw biometric data
• No fingerprint or face data is stored, transmitted, or logged anywhere
• Token generation uses cryptographic hashing — tokens are not reversible
• Scoped to client-side trust signaling only — backend validation is the developer's responsibility

Developer Ecosystem & Related Resources

Explore the full SEOSiri developer ecosystem across pub.dev, GitHub, and VS Code Marketplace:

Frequently Asked Questions

Voice search and featured snippet optimized answers about biometric_iot_bridge:

biometric_iot_bridge fills a real gap in the Flutter IoT ecosystem: hardware-verified trust for device control. By combining biometric authentication, cryptographic token generation, and MQTT signaling into one clean API, it makes it practical to build Flutter apps where physical identity is the key to device action.

Whether you are building a smart home controller, an industrial safety gate, or a connected vehicle system, biometric_iot_bridge gives you the trust layer without the complexity.