On-device encryption means an app encrypts and decrypts protected content on the device. That phrase alone does not explain where keys live, whether another readable copy exists, how recovery works, or what happens after export. Evaluate those four boundaries before trusting a vault with important files.
On-device describes where encryption happens
Encryption transforms readable content into data that requires a key to interpret. On an iPhone, the operating system also provides Data Protection and hardware-backed key-management features. Apple explains that foundation in its Encryption and Data Protection overview.
An app can add its own encryption and access rules on top of the platform. “On-device” should identify the content covered and whether encryption and decryption occur locally. It should not be expanded into a promise that every related datum stays off every external service.
Ask about keys, copies, recovery, and export
- Keys: What secret or device protection controls decryption?
- Copies: Does the provider, a cloud service, or a device backup hold another copy?
- Recovery: What can a recovery key restore, and what can support do?
- Export: What protection applies after readable files leave the vault?
These questions are more useful than a broad security adjective. They expose the points at which access changes.
Calculator Lock keeps vault content local, not purchase processing
| DATA OR FUNCTION | CURRENT BOUNDARY |
|---|---|
| Vault content | Encrypted and stored locally on the iPhone. |
| Calculator code and recovery material | Processed for local vault access and recovery. |
| Cloud backup and sync | No Calculator Lock account, launch cloud backup, or cross-device sync. |
| Purchase status | Apple and RevenueCat process transactions and entitlement status. |
RevenueCat receives anonymous purchase history and transaction status to validate purchases and provide subscription functionality. It does not receive vault content. This distinction is why “local vault content” is more accurate than claiming that the entire app processes no external data.
The Calculator Lock photo vault uses a working calculator, a visible Private Vault button, and a separate vault code. Premium is required to add new content.
Recovery can restore access without recreating deleted data
Calculator Lock generates a recovery key that the user saves. A valid key can support choosing a new calculator code. Support cannot regenerate the key, bypass the vault encryption, or open the content.
Compare this boundary with the copy and backup choices in iCloud and local-only apps.
Exported copies need their own protection
- Vault items remain protected by the vault while stored inside it.
- Export creates readable copies for another app or destination.
- The destination may sync, back up, preview, or share those files under different rules.
- Calculator Lock’s current export workflow is available while private-vault Premium access is active.
Use the export checklist to verify the files and choose a destination you control.