Project Overview
Calculator Vault is a production-grade Android application that perfectly conceals a full-featured encrypted media vault behind a working scientific calculator. Built with Kotlin and Jetpack Compose, it follows Clean Architecture with 18 dedicated use cases, giving users airtight content privacy.
The Challenge
Users needed a truly private space for sensitive files without any obvious "vault app" icon or login screen that could signal its existence. Standard file lock apps are easily identifiable and add friction. The solution had to be genuinely secure — not just visually obscured — while still feeling like a premium, fluid Android experience.
Our Solution
We built Calculator Vault with dual-layer protection: security-through-obscurity (a fully functional calculator as the entry point) combined with real AES-grade, on-device encrypted storage in app-private space inaccessible to all other apps. The PIN is hashed and stored via Jetpack DataStore, never in plain text. The vault is accessed by entering a secret PIN directly on the calculator keypad — no login screen, no vault icon on the home screen.
The Results
The result is a polished, production-ready Android application indistinguishable from a standard calculator app. It manages photos, videos, and files with date-grouped grids, full-screen viewers, multi-select bulk actions, real-time search, shimmer loading, and smooth Material 3 animations — all with zero traces visible from the device home screen.
Key Innovations
The defining features and technical breakthroughs that power this solution.
Disguised Calculator Entry
Secret PIN entered on a fully functional calculator opens the hidden vault — no login screen visible.
On-Device Encryption
All vault files stored in app-private storage with hashed PIN authentication — inaccessible to all other apps.
Photo, Video & File Vaults
Date-grouped grids, full-screen viewers, multi-select bulk actions, and real-time search across all media types.
Clean Architecture (MVVM)
18 single-responsibility use cases with strict layer separation, Hilt DI, and type-safe Jetpack Navigation.
Premium Material 3 UI
Haptic feedback, shimmer skeletons, animated transitions, and adaptive layouts for portrait and landscape.
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