Owned the end-to-end product build — architecture, UI/UX, encryption vault, authentication, monetization, and store release — shipping QEncrypt live on the App Store for iPhone and Mac (~280 active iOS and 78 active macOS users).
What I built:
- On-device encryption engine using hybrid AES-256-GCM with Kyber512 (post-quantum KEM) key agreement and PBKDF2-HMAC-SHA256 key derivation, with a secure key hierarchy where keys are never stored in clear.
- Master-password and Face ID / biometric unlock via the iOS Keychain, chunk-based encrypted file storage, and encrypted vault backup/restore.
- Offloaded encryption, decryption, and login verification to background isolates for a responsive UI on large files.
- Native iOS secure file viewer through Swift platform channels, with screenshot controls that prevent leakage of decrypted photos, videos, and documents while open.
- Free-versus-premium gating with StoreKit 2 — monthly and yearly subscriptions, purchase restore, and free-tier limits — with subscription status synced to a WordPress REST backend.
- Push notifications (FCM), install/event attribution (AppsFlyer, Meta App Events), and App Tracking Transparency for privacy-compliant analytics.
- Riverpod state architecture, onboarding and paywall flows, and full App Store compliance — privacy policy, terms/EULA, encryption documentation, ATT, and IAP review.
