🔐 OtpAuth - Secure 2FA Authenticator with Cloud Sync

OtpAuth is a modern, privacy-focused Two-Factor Authentication (TOTP) app for Android built entirely with Kotlin and Jetpack Compose. It offers robust security features including biometric protection, zero-knowledge cloud backups via Google Drive, and full offline support.

Designed for security enthusiasts who want full control over their 2FA tokens without relying on proprietary, lock-in solutions.

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📸 Screenshots

Home Screen	Scan QR	Settings	Dark Mode

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🚀 Key Features

🔐 Security First

• Zero-Knowledge Encryption: All backups (Cloud & Local) are encrypted with AES-256-GCM using a custom password before leaving the device.
• Biometric Protection: Secure the app launch and critical actions (like deleting accounts or overwriting backups) with Fingerprint or Face ID.
• Secure Storage: Keys are stored in EncryptedSharedPreferences backed by the Android Keystore System.
• Privacy Screen: Prevents screenshots and obscures app content in the "Recent Apps" view.

☁️ Cloud & Local Sync

• Google Drive Sync: Seamlessly backup/restore your accounts to a hidden, secure folder in your personal Google Drive (appDataFolder).
• Local Import/Export: Export your vault to an encrypted .json file for offline storage or transfer between devices.
• Overwrite Protection: Biometric confirmation is required before overwriting existing cloud or local backups.

📲 User Experience

• Google Authenticator Migration: Supports scanning otpauth-migration:// QR codes to easily transfer accounts from Google Authenticator.
• Modern UI: Built with Material 3 and Jetpack Compose for a smooth, adaptive experience.
• Theming: Full support for Dark Mode, Light Mode, and System Default.
• ML Kit Scanner: Fast and accurate QR code scanning using Google's ML Kit and CameraX.

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🛠️ Tech Stack & Libraries

• Language: Kotlin
• UI Framework: Jetpack Compose (Material3)
• Architecture: MVVM (Model-View-ViewModel)
• Asynchronous: Kotlin Coroutines & Flow
• Security:
  • androidx.security:security-crypto (EncryptedSharedPreferences)
  • androidx.biometric (BiometricPrompt)
  • javax.crypto (AES/GCM/NoPadding)
• Cloud/Network:
  • Google Drive API v3 (Rest V3)
  • Google Sign-In
• Camera/Scanning:
  • CameraX
  • ML Kit Barcode Scanning
• Data Serialization: Gson (JSON Parsing)

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⚙️ Setup & Installation

Prerequisites

• Android Studio Ladybug (or newer)
• JDK 17+
• A Google Cloud Project (for Drive Sync)

1. Clone the Repository

git clone https://github.com/shoaibhassan2/OtpAuth.git
cd OtpAuth