NullKey Privacy Policy
Effective date: 5 November 2026
NullKey is an Android app provided by Alvento Ltd, United Kingdom. Contact us about privacy or support at hello@alvento.uk. This policy applies to NullKey's offline encrypted vault and its local unlock, import, backup and export functions, and its optional one-time purchase.
Your vault stays on your device
NullKey has no account, server connection, analytics, advertising SDK or automatic crash-reporting service. The app does not declare Android's INTERNET permission. Alvento does not receive your vault contents, filenames, passphrase, recovery key, device identifiers or usage activity through the app.
NullKey accesses the files you choose using Android's system picker. Photos may include embedded location metadata; preserving the selected file preserves that metadata inside the encrypted vault. Files, photos and notes are encrypted in the app's private storage. Names, types, sizes and dates are held in an encrypted index. Local settings, unlock-method state and attempt counters are also stored on the device. Android may retain selected-file permissions and pending import references.
While you use an unlocked vault, readable content and encryption keys are processed in memory. Keyboards, accessibility services and a compromised operating system may access information you type or display. Screenshot blocking and keyboard privacy hints cannot protect against every device or third-party application.
Unlock methods
Your passphrase and recovery key unlock the vault. Alvento has neither and cannot recover a lost secret or missing files. Optional biometric and phone screen-lock authentication are handled by Android: NullKey does not receive your fingerprint, face data or phone PIN. Android Keystore keys protect device-local copies of the vault key. Hardware support varies by device; the app requires hardware backing for screen-lock and pattern unlock in release builds.
The optional NullKey pattern is processed locally. NullKey stores a sealed vault-key copy and attempt counters, not the drawn pattern. Patterns are weaker than passphrases and per-use biometric authentication. Anyone who can satisfy an enabled unlock method can open the vault.
Transfers you choose
You can create an encrypted backup, export a readable copy, copy text to the clipboard, or open Alvento's website in your browser. These actions are optional and are initiated by you. Your chosen document or cloud provider may sync, retain or otherwise process a saved file under its own policy. A readable export is no longer encrypted by NullKey. A backup still requires its passphrase or recovery key.
Clipboard previews are marked sensitive, and NullKey attempts to clear its clip after 30 seconds when Android permits it. Clipboard managers and other apps may retain copies. The browser link sends no vault content; browsing alvento.uk is covered by the website's separate privacy policy.
Storage, retention and deletion
The local vault remains until you delete items, delete the vault, clear app storage or uninstall. Android cloud backup and device-transfer backups are disabled for the app. Keep your own encrypted backups: uninstalling or losing the phone may otherwise lose the only copy.
Temporary files used by NullKey for imports and backup verification contain ciphertext. Readable exports are written only to the destination you choose. Interrupted exports may leave a partial copy at that destination if its provider cannot remove it.
Optional removal of originals requires verification of the encrypted copy. Photos and videos are submitted to Android's trash confirmation where supported; other selected documents can be permanently deleted. Sync providers may propagate deletions. Deleting a vault or file is not a guaranteed secure erase on flash storage. Originals, exports, old backups, clipboard history and other providers' copies are not removed by deleting the vault.
Optional purchase
NullKey is free for up to 30 items. You can buy an optional one-time unlock, NullKey Unlimited, inside the app. Google Play processes the payment and any refund under Google's terms and privacy policy. Alvento does not receive your payment card or payment account details. Google provides us with order information as the seller, such as the order and product details.
To show the price and confirm your purchase, NullKey asks the Google Play service on your phone. NullKey keeps a small local record on your device of whether the unlock is active and when Google Play last confirmed it. This does not send vault contents, filenames or keys to Google or Alvento. The app declares Google Play's billing permission and still does not declare Android's INTERNET permission. Buying and restoring the unlock need Google Play and an internet connection; your vault works offline.
Contacting Alvento
If you email us, we receive your address and whatever you include. Do not send passphrases, recovery keys or private vault contents. We use correspondence to answer the request and maintain necessary support records, based on our legitimate interest in providing support. We keep it only as long as necessary for that purpose or to meet applicable legal obligations. Our email provider processes correspondence on our behalf under its service terms; email and website services are separate from the offline app.
You can contact hello@alvento.uk to request access, correction or deletion of personal information held in support correspondence, or raise a privacy concern. You may also complain to the UK Information Commissioner's Office at ico.org.uk. Alvento cannot access or erase your local vault remotely; use the app or Android's storage controls.
Changes
If NullKey's data practices change, we will update this policy and its effective date. Adding network-based features would require a new app version and updated disclosures. Older versions retain the behaviour implemented in those versions.