Secret Contacts: Locked Book
Encrypted phone list, Face ID
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
Two address books: the one anybody can open, and this one. Four digits or a glance to get in, and the entries stay encrypted on the phone itself.
Two address books are better than one.
The contacts app that came with your phone is fine for most of the people in your life. This one is for the rest of them. It opens with a code only you know, and shows nothing at all until it does.
Setting it up takes about ten seconds
Choose four digits the first time you launch the app. They have nothing to do with the code on your Lock Screen, and neither one will open the other. After that it is four taps — or a glance, once you switch Face ID on.
An entry can hold
A name. A phone number. An email address. And a memo line, which is where most of the useful part tends to end up: how you met, which of the numbers is the work one, what was said last time, what you still owe.
It shuts itself
There is no lock button to remember and no timer to configure. Swipe up, take a call, check a message — by the time you come back it is asking for the code again.
Where the numbers actually sit
Inside this phone, in a file AES-GCM has already scrambled, with the key held in the device keychain. Nothing is uploaded, because there is nowhere to upload it to: the app has no account system and never asks for an email address. Switch the network off completely and it behaves exactly the same.
One warning. Uninstalling the app takes the entries with it, permanently, and nobody — the developer included — can bring them back. Write your four digits down somewhere safe.
Ads cover the cost of the app. A single in-app purchase turns them off for good.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
The app is now called Secret Book, so the name under the icon on your Home Screen changes with it.
Numbers and email addresses now sit behind dots in the list. Tap a row and only that one entry opens.
Added a search that covers names, numbers and memos, plus letter headings and an index down the right edge.
The lock screen and passcode setup were rebuilt: a dark screen with the number pad right on it, no separate sheet.
The developer, MIZOU, CO., LTD., indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Used to Track You
The following data may be used to track you across apps and websites owned by other companies:
- Identifiers
- Usage Data
Data Linked to You
The following data may be collected and linked to your identity:
- Identifiers
- Usage Data
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Diagnostics
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- MIZOU, CO., LTD.
- Size
- 5.4 MB
- Category
- Productivity
- Compatibility
Requires iOS 18.0 or later.
- iPhone
Requires iOS 18.0 or later. - iPad
Requires iPadOS 18.0 or later. - Mac
Requires macOS 15.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 2.0 or later.
- iPhone
- Languages
English and 32 more
- English, Arabic, Catalan, Croatian, Czech, Danish, Dutch, Finnish, French, German, Greek, Hebrew, Hindi, Hungarian, Indonesian, Italian, Japanese, Korean, Malay, Norwegian Bokmål, Polish, Portuguese, Romanian, Russian, Simplified Chinese, Slovak, Spanish, Swedish, Thai, Traditional Chinese, Turkish, Ukrainian, Vietnamese
- Age Rating
4+
- 4+
- Contains
Advertising
- In-App Purchases
Yes
- Remove Ads $1.99
- Copyright
- © 2026 Mizou Co., Ltd.