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How to Lock Private Notes and Secret Diary on iPhone

iOS 18 Face ID lock and Hidden folder · Tigran Mkhitaryan · checked November 2026

Time needed
4 taps
Needs iOS 18 or later

Works for Private Notes and Secret Diary whether or not it has its own passcode. No download needed.

Short answer

Touch and hold Private Notes and Secret Diary's icon, tap Require Face ID, then confirm. On iOS 18 and later that puts Private Notes and Secret Diary behind Face ID, Touch ID or your passcode; choose Hide and Require Face ID instead to move it into App Library's Hidden folder as well.

Lock Private Notes and Secret Diary with Face ID

  1. Find Private Notes and Secret Diary on your Home Screen or in App Library.
  2. Touch and hold the icon until the quick-actions menu opens.
  3. Tap Require Face ID (or Require Touch ID / Require Passcode, depending on your iPhone).
  4. Tap Require Face ID again to confirm. Private Notes and Secret Diary now asks for authentication every time it opens.

To test it, close Private Notes and Secret Diary from the App Switcher and open it again. You should see the Face ID prompt before any content appears.

Hide Private Notes and Secret Diary in App Library

  1. Touch and hold Private Notes and Secret Diary's icon and tap Require Face ID.
  2. Choose Hide and Require Face ID instead of Require Face ID.
  3. Confirm. The icon leaves your Home Screen and moves to the Hidden folder at the bottom of App Library.
  4. To open it later, swipe to App Library, tap Hidden and authenticate.

Hiding also locks the app. To undo either, touch and hold the icon again and choose Don't Require Face ID.

Why lock Private Notes and Secret Diary?

Private Notes and Secret Diary is a encrypted notes app, the kind of app that tends to hold personal information you would not want on screen if someone borrows your unlocked phone. Notes apps quietly collect some of your most personal writing. 'Encrypted' can mean encrypted in transit, at rest on the server, or end-to-end — only the last keeps the developer out.

Productivity apps tend to collect the work you do in them — documents, notes and files — so User Content is common. The question is whether it syncs to the developer's servers and how it is protected there.

A lock answers one question — who can open the app on this iPhone. It does not change what Private Notes and Secret Diary sends to its developer; for that, see Private Notes and Secret Diary's full privacy report.

What the lock does and does not do

It does

  • Ask for Face ID, Touch ID or passcode every time Private Notes and Secret Diary opens
  • Hide message previews in notifications
  • Keep Private Notes and Secret Diary's content out of Spotlight and Siri suggestions
  • With Hide, remove the icon from the Home Screen

It does not

  • Stop someone who knows your passcode
  • Encrypt or change how Private Notes and Secret Diary stores data
  • Sync to your iPad or other devices
  • Remove Private Notes and Secret Diary from purchase history or Screen Time reports

Don't see Require Face ID?

  • Update to iOS 18 or later in Settings › General › Software Update.
  • Make sure a passcode is set in Settings › Face ID & Passcode; the lock needs one.
  • Some Apple apps (Settings, Calculator, Camera, Maps, Find My, Clock) cannot be locked or hidden.
  • If your iPhone is managed by work or school, the option may be restricted.

Other settings worth checking for Private Notes and Secret Diary

  1. Notifications

    Settings › Notifications › Private Notes and Secret Diary › Show Previews: When Unlocked keeps message and account details off the Lock Screen.

Private Notes and Secret Diary's full privacy label

App Privacy label Developer-reported · checked November 1, 2026
Data Not Collected

The developer states that no data is collected from this app.

Is Private Notes and Secret Diary safe? Every data type explained →

Lock these apps too

After you lock Private Notes and Secret Diary

Tick what you have done
Tick each step as you do it on your iPhone.

Done. You have applied every control the label points to.

FAQ

Does Private Notes and Secret Diary have its own passcode?
Some apps offer an in-app PIN or biometric lock in their settings. The App Store privacy label does not say whether Private Notes and Secret Diary does; the iOS 18 lock works regardless.
What happens to Private Notes and Secret Diary's notifications when it is locked?
Locked and hidden apps do not show message previews or content in notifications, and their content does not appear in Spotlight search or Siri suggestions.
Can someone who knows my passcode open a locked app?
Yes. If Face ID fails, the lock falls back to your device passcode. Keep the passcode private if the lock matters to you.
Is a locked Private Notes and Secret Diary encrypted?
The lock controls who can open the app on this iPhone. It does not change how the app stores or syncs data. Encryption depends on the developer and on your device passcode.
Why can't I see the Require Face ID option?
You need iOS 18 or later. Some Apple apps such as Settings, Calculator, Maps and Camera cannot be locked or hidden.
Does hiding Private Notes and Secret Diary remove it from my purchase history?
No. Hidden apps still appear in App Store purchases and in Settings › Apps, and Screen Time reports still include them.

Is Private Notes and Secret Diary safe? Full privacy report →Does Private Notes and Secret Diary track you? →Lock an app: A–Z →All productivity apps →

Facts on this page come from Apple: lock or hide an app on iPhone, as reported by the developer. Checked November 2026. How we collect data · Report a correction