🛡️ Zero-Trust Tasks

A privacy-first, local-first task manager built with Flutter.

🌟 Key Features

• Client-side encryption: Tasks are encrypted locally before storage/sync.
• Authenticated encryption: Uses AES-256-GCM.
• Password-based key derivation: Uses PBKDF2-HMAC-SHA256 with a high iteration count.
• Secure secret storage: Salt and verification blob are stored in iOS Keychain / Android Keystore via flutter_secure_storage.
• Cloud Sync (encrypted backup): Upload/download encrypted backup blobs to Google Drive appDataFolder.
• Session hardening: In-memory session key with idle timeout and login backoff.

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🔒 Security Architecture

1. Derive key from master password using PBKDF2-HMAC-SHA256 + random 32-byte salt.
2. Encrypt/decrypt task JSON using AES-256-GCM (nonce + auth tag).
3. Persist encrypted data in SharedPreferences as ciphertext blob.
4. Store security metadata in secure storage (salt + verification payload).
5. Cloud backup uploads only encrypted payloads.

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🚀 Getting Started

Prerequisites

• Flutter SDK (3.0+)
• Google Cloud / Google Sign-In setup for Drive backup sync

Installation

git clone https://github.com/EdoSag/Zero-Trust-Tasks.git
cd Zero-Trust-Tasks
flutter pub get
flutter run

For Google Drive sync, add google-services.json (Android) and GoogleService-Info.plist (iOS) per Flutter Google Sign-In docs.

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🛠️ Built With

• Flutter
• pointycastle (PBKDF2 + AES-GCM primitives)
• flutter_secure_storage
• google_sign_in + googleapis (Drive app data backup)