Privacy Policy
Last updated: June 2026
Summary
Arcanum does not collect, transmit, or share any of your personal data. The app works entirely offline and has no internet permission. Everything you create stays on your device, encrypted, under your control.
What Arcanum Does NOT Do
- ✕ Arcanum does not Require internet access
- ✕ Arcanum does not Collect analytics or usage statistics
- ✕ Arcanum does not Use crash reporting or telemetry services
- ✕ Arcanum does not Contain advertising or third-party trackers
- ✕ Arcanum does not Transmit your files, passwords, or metadata anywhere
- ✕ Arcanum does not Access your contacts, location, or other apps' data
Data Stored On Your Device
All data created and used by Arcanum remains exclusively on your device:
Encrypted vault files
VeraCrypt-compatible containers (e.g. .hc or any extension you choose): stored where you choose, never transmitted.
App PIN
Used to unlock Arcanum: stored as a SHA-256 hash in Android's EncryptedSharedPreferences (AES-256-GCM, Keystore-backed). The raw PIN is never stored.
Container passwords
Never stored on disk. They exist only in memory during an active mount session. If you enable biometric unlock for a vault, the password is encrypted with a Keystore-backed biometric key — still never leaving your device.
Biometric credentials
Managed entirely by Android's Keystore system. Arcanum never has access to your raw biometric data (fingerprint, face), only to Keystore-backed cryptographic keys.
App settings and preferences
Stored locally via Android DataStore.
Vault metadata
Names, paths, last-mounted times: stored locally in a standard SQLite database (via Android Room). This database is not encrypted at rest, but it contains only metadata — the actual file content always remains inside VeraCrypt-encrypted containers.
None of the above is ever transmitted to us or any third party, because Arcanum has no network connectivity at all.
Privacy-Protective Features
Arcanum is built with privacy as a first principle, beyond just encryption:
Screenshot protection
Arcanum sets the FLAG_SECURE window flag, which prevents the OS and third-party screen recorders from capturing the app's contents. The app will appear blank in the system recents screen.
Calculator disguise
Arcanum can disguise itself on your home screen and in the app drawer as a plain calculator. The real app is only accessible by entering your PIN in the calculator interface.
Panic PIN
A second PIN can be configured to trigger an emergency action (panic wipe) instead of opening the app.
Permissions Explained
Arcanum requests only the permissions necessary for its core functionality:
| Permission | Purpose |
|---|---|
| READ / WRITE / MANAGE _EXTERNAL_STORAGE | To access vault files stored on external storage. On Android 11+, MANAGE_EXTERNAL_STORAGE ("All Files Access") is required to open containers outside app-private directories. |
| USE_BIOMETRIC USE_FINGERPRINT | To unlock the app and your vaults using your device's biometric hardware (optional). |
| FOREGROUND_SERVICE _DATA_SYNC | To run the container creation process as a foreground service, ensuring it completes reliably even when the app is in the background. No data is transmitted. |
| usb.host (optional) | To allow storing vaults on external USB drives or SD cards connected via OTG. |
Arcanum does not request internet, location, contacts, microphone, or any permission unrelated to local file encryption.
Google Play Billing (Play Store version only)
If you purchase the Pro upgrade through the Google Play Store, the transaction is processed entirely by Google Play Billing. We do not receive or store your payment information. Please refer to Google's Privacy Policy for details on how Google handles billing data.
The F-Droid version of Arcanum does not include any billing or payment functionality and all features are available for free.
Open Source
Arcanum is open source. You can review the complete source code at:
github.com/Esdex/ArcanumWe encourage security researchers and privacy-conscious users to audit the code themselves rather than simply trusting this policy.
Children's Privacy
Arcanum does not knowingly collect any data from anyone, including children, because it does not collect data from anyone at all.
Changes to This Policy
If this policy ever changes (for example, if a future feature requires network access), we will update this page and clearly note the change, along with the date of the update.
Contact
Questions about this Privacy Policy can be raised via GitHub Issues:
github.com/Esdex/Arcanum/issues