Flutter 2FA

🔐 A Flutter package to add secure Two-Factor Authentication (2FA) via time-based one-time passwords (TOTP) to any Flutter application with ease.

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📸 Screenshots

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✨ Features (v1.0.5 Upgrade)

• Quick Setup: Generates a standard cryptographically secure TOTP secret key compatible with Google Authenticator, Microsoft Authenticator, Authy, etc.
• QR Code Generation: Integrated visual setup flow using dynamic QR codes.
• Copy-to-Clipboard: Fallback configuration flow allowing users to copy the raw setup key manually.
• Secure OTP Verification: Standard input interface using high-quality pin inputs (pinput integration).
• 🎨 Custom UI Themes: Override background colors, text colors, AppBars, button styles, and PIN input decorations to match your app's design system.
• 🔒 Secure Storage: Optional encrypted storage backend via flutter_secure_storage to secure secret keys and recovery codes.
• 🛡️ Biometric Authentication: Quick local unlock (Face ID / Touch ID / Fingerprint) via local_auth integration.
• 🧩 Backup Recovery Codes: Generates 10 static recovery codes during activation. Displayed under a space-saving collapsible accordion. Users can use these codes as a login fallback.
• ⚙️ Configurable TOTP Settings: Configure digit length, intervals (e.g. 30s/60s), and hashing algorithms (SHA1, SHA256, SHA512).

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📦 Installation & Dependency Upgrades

Add flutter_2fa and its required biometric and secure storage backend packages to your pubspec.yaml:

dependencies:
  flutter_2fa: ^1.0.5
  local_auth: ^2.3.0
  flutter_secure_storage: ^9.2.4

Or install them directly:

flutter pub add flutter_2fa local_auth flutter_secure_storage

⚙️ Android Toolchain Requirements

To compile successfully with newer dependency versions (e.g. Kotlin 2.x and Java 21), make sure your Android project files are configured as follows:

• Gradle Wrapper: Version 8.14.0 or higher (gradle-wrapper.properties).
• Android Gradle Plugin (AGP): Version 8.11.1 or higher (settings.gradle).
• Kotlin: Version 2.2.20 or higher (settings.gradle).
• Compile SDK: Version 34 or higher (app/build.gradle).

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🚀 Usage

1. Configure Options (New in v1.0.5)

Define a Flutter2FAConfig configuration object:

import 'package:flutter/material.dart';
import 'package:flutter_2fa/flutter_2fa_config.dart';

final twoFactorConfig = Flutter2FAConfig(
  useSecureStorage: true,   // Encrypts stored secret keys in Keychain/Keystore
  allowBiometrics: true,    // Enables Face ID/Touch ID quick unlock
  totpInterval: 30,         // TOTP step interval (in seconds)
  totpDigits: 6,            // OTP digit length
  totpAlgorithm: 'SHA1',    // Hashing algorithm
  
  // Custom Styles
  backgroundColor: Colors.grey[50],
  textColor: Colors.indigo[900],
  appBarColor: Colors.indigo,
  primaryButtonStyle: ElevatedButton.styleFrom(
    backgroundColor: Colors.indigo,
    foregroundColor: Colors.white,
  ),
);

2. Activating 2FA Setup Flow

Trigger the initialization UI screen where the user is shown the secret seed key, the setup QR code, and collapsible backup recovery codes.

import 'package:flutter_2fa/flutter_2fa.dart';

void activateTwoFactor(BuildContext context) async {
  await Flutter2FA().activate(
    context: context,
    appName: "Your App Name",       // App name shown in Authenticator app
    email: "user@example.com",     // User email identifier for the account
    config: twoFactorConfig,       // Pass the custom config
  );
}

3. Verifying a 2FA Login Session

Trigger the OTP input, biometric verification prompt, or backup recovery code input.

import 'package:flutter_2fa/flutter_2fa.dart';

void verifyTwoFactor(BuildContext context) async {
  await Flutter2FA().verify(
    context: context,
    page: const DashboardScreen(),  // Redirect target widget upon successful validation
    config: twoFactorConfig,       // Pass the custom config
  );
}

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🛠️ Contribution

Contributions, issues, and feature requests are very welcome! Feel free to open a pull request or file an issue.

📄 License

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