Overview
Units: Ruler & Vault is a working on-screen ruler for iPhone and Android with a private vault behind it. Anyone who opens the app sees a ruler and nothing else. To reach the vault, open Settings, tap the plain "About" line at the bottom and draw your pattern.
Key Features
- Real ruler in millimeters, centimeters and inches, with an optional second unit.
- Each pattern opens its own vault. There is no list of vaults, so nobody can tell how many you have.
- Keep photos, videos, files and notes. Take photos and videos straight into the vault; they never touch your camera roll.
- Import notes from other apps with the share menu, and move items back out with "Take out".
- Encrypted on the phone with AES-256-GCM. Patterns are stretched with PBKDF2-HMAC-SHA512 (600,000 rounds).
- No account, no server, no analytics. Files never leave your phone.
- The vault locks as soon as you leave the app.
No Recovery, by Design
There is no recovery email and no master key. If you forget a pattern, nobody can open that vault, including the developer. Every recovery method is also a way in for someone else, so Units has none.
Use Cases
- Keeping private photos out of sight when you hand your phone to someone.
- Storing copies of IDs, receipts or contracts outside your main photo library.
- Private notes that should not sit in a regular notes app.
Getting Started
Install from the App Store or Google Play, create a pattern of at least four points, and draw it again to confirm.
Pricing
Free: unlimited vaults, with 50 photos, 10 videos, 20 files and 10 notes per vault. Pro: a single one-time purchase of US $32.99 that removes the limits and adds an emergency pattern. No subscription.
