HollowNickel: Encrypted Notes

Hollow Nickel is a handwritten notebook for iPad. You write with your stylus, and what you write stays encrypted on your device. - Ink, typed text and photos on the same page - A4, A5 and Letter formats; blank, ruled, grid or dotted backgrounds - AES-256-GCM encryption of every single page, on the device - No account, no server, no iCloud sync - Unlock with a passcode or Face ID / Touch ID - Plain PDF export; password-protected and highly protected export with Pro - Companion Mac app to read your notebooks back, included in Pro - Search across every notebook, handwriting included - Rectangles, circles and arrows straightened by holding still - No data collected, no ads - 14-day trial, then a one-time purchase; never a subscription WRITE THE WAY YOU WOULD ON PAPER The ink is vector-based: it stays sharp at any zoom level and can be corrected stroke by stroke. Pick your tool, colour and thickness, add a typed text box for a title or a caption, import a photo and place it anywhere on the page. BUILT FOR MEETINGS AND LECTURES Create one notebook on the free version, as many as you like with Pro, add a page without leaving the writing screen, rename a page or delete it. The editor fills the whole screen, with no wasted chrome, and the columns swap sides depending on whether you write with your right or left hand. YOUR NOTEBOOKS NEVER LEAVE YOUR IPAD No account to create, no server, no iCloud sync: the only copy of your notebooks lives on your iPad, encrypted with AES-256-GCM, page by page and photo by photo. Nothing is ever written to the file system in the clear. A KEY ONLY YOU HOLD The key that decrypts your notebooks is protected by your passcode (4 digits, 6 digits or a free-form passphrase) and, if you want it, by Face ID or Touch ID backed by the Secure Enclave: a non-extractable hardware key, not a plaintext copy sitting behind biometrics. A recovery phrase, shown once during setup, gets you back to your notebooks if you forget your code. A dedicated screen explains in plain words what each layer really protects, and what it does not. EXPORTING STAYS AN EXPLICIT DECISION Keeping is always encrypted and local. Exporting is a deliberate, one-off act, re-confirmed with your passcode every time. Three levels: plain PDF, free; password-protected PDF and a highly protected package only the companion Mac app can open, with Pro. Export a whole notebook or a single page, and name the file yourself. No temporary file is written to disk along the way. THE COMPANION MAC APP A read-only safety net if your iPad is lost or broken: the free Mac app, distributed by Precellence Software outside the App Store, opens the highly protected packages and displays your notebooks. Pairing happens over a QR code, straight between your two devices, with no server, using a hybrid X25519 + ML-KEM-768 key exchange designed to hold up against future quantum computers. Pairing is part of Pro. PRIVACY The developer collects no data: no ads, no trackers, no usage analytics. The app works entirely offline. SIMPLE PRICING Free with no time limit: one notebook, unlimited pages, plain PDF export, every security feature. The 14-day trial, started whenever you decide, unlocks all of Pro: unlimited notebooks, password-protected PDF, highly protected export, Mac pairing. When it ends nothing is locked, your notebooks stay readable, editable and exportable. Pro is a one-time purchase, never a subscription. WHERE THE NAME COMES FROM In 1953, in Brooklyn, a hollowed-out nickel slipped from a paperboy's hand and spilled a strip of encrypted microfilm. It took four years, and the defection of the man it was addressed to, before anyone could read it. A screen inside the app tells that story, with sources.