Project Profile: Indac

Overview

Indac (Instant Document Access) is a highly secure, privacy-first mobile document vault built with Flutter. It allows users globally to scan, encrypt, and organize critical identity documents, travel visas, academic records, and medical papers entirely on-device without relying on third-party cloud servers.

Core Architecture & Security

• Framework: Flutter (Cross-platform iOS & Android compiling to native machine code).
• Database: Isar or Hive (Lightweight, local NoSQL databases supporting native encryption).
• Cryptography: AES-256 (GCM mode) for file encryption. The encryption key is generated locally on first boot.
• Hardware Security: The master key is stored in the device's secure enclave (KeyChain for iOS / Keystore for Android) via flutter_secure_storage. Files are never stored in plaintext on the device disk.
• Biometric Gate: App access is restricted via FaceID / TouchID / Device PIN using local_auth.

Global & Unique Features

1. Smart Expiry & Renewal Intelligence: On-device text recognition (OCR) scans international documents (like passports or driver's licenses) for expiry dates and automatically schedules local, automated device notifications to alert the user before they expire.
2. Dynamic Watermarked Sharing: Allows exporting password-protected PDFs with a custom, semi-transparent watermark (e.g., "Shared for car rental only on [Date]") to prevent identity theft.
3. OS-Level Privacy Protection: Prevents in-app screenshots and automatically blurs or hides the app UI screen when viewed in the mobile OS app-switcher drawer.
4. Duress Vault: A secondary PIN system that loads a completely fake, benign "decoy" vault if the user is physically forced to unlock the app under coercion.
5. Air-Gapped "Local Only" Backup: Encrypts and zips the vault database into a single backup file that users can export to a physical thumb drive or local computer, ensuring data never touches a cloud server.

Essential Package Stack

• flutter_secure_storage (Hardware-backed key storage)

• encrypt (AES-256 implementation)

• local_auth (Biometrics)

• secure_application (Screen privacy & screenshot blocking)

• google_mlkit_document_scanner (Edge-detection camera scanner)

• google_mlkit_text_recognition (On-device OCR for smart expiry detection)

• isar or hive_flutter (Encrypted metadata storage)

• Write the Flutter helper class for AES-256 encryption

• Create the document metadata database model

• Design the main dashboard UI screen code