How CalcLock handles privacy

Different layers do different jobs

A discreet interface, encryption and a backup plan solve different problems. The calculator is the way you enter a collection. Encryption protects stored file contents. Your device security helps protect the phone and the keys it holds. An independent copy is what keeps a collection from becoming your only copy.

Use these layers together. An ordinary-looking screen is not proof that an app is invisible, and a named encryption algorithm is not a promise against every way someone could access an unlocked or compromised device. This page explains the actual boundaries of the product rather than assigning a security score.

The exact equation opens the collection

The expression you enter identifies the vault. Two expressions with the same answer do not open the same collection. The first equals press performs the calculation; the second consecutive equals press opens the matching vault. Changing the expression cancels that pending entry sequence.

There is no visible directory of every vault and no master unlock that opens all collections. That is an interface choice, not a guarantee that the presence of stored app data cannot be discovered. Choose an equation you can reproduce accurately, keep it private and do not use the public example shown on this website as a personal credential.

Files and manifests are encrypted on the device

The app combines your exact equation with a secret generated on your device, then uses key-derivation steps including PBKDF2-HMAC-SHA256. AES-256-GCM encrypts the vault’s files and its manifest, which holds their names. Two equations with the same answer, such as 123+123 and 200+46, produce different keys and open different vaults.

The device secret is stored in the iPhone’s Keychain and does not sync to another device. It is not a portable backup key. Content must be decrypted to display it, so encryption at rest does not protect a photo already visible on an unlocked or compromised device.

A simple equation is easier to guess. This encryption design has not had an independent security audit, so it should not be described as unbreakable.

Locking reduces accidental exposure

Leaving or backgrounding the app returns it to the calculator and clears the equation. The app also puts an opaque cover over its own interface during the transition to the app switcher. Those behaviors help avoid leaving a collection open during ordinary use.

They do not make displayed content impossible to capture. Another camera can photograph the screen, and screenshots are not universally preventable. Screen-recording detection is not a substitute for deciding who can see the phone while a collection is open. Lock the device itself when you finish using it.

Imports make copies, not disappearances

Importing from Photos or Files creates a local copy inside the selected vault. CalcLock does not automatically delete the source. A picture may still exist in Photos, a cloud library, a shared album, a message or the Files provider used to import it.

A still photo captured with the app's camera is added to the current vault without automatically being saved to Photos. Consider that difference before capturing something irreplaceable: a direct capture does not create an independent original for you. For important material, use a workflow that keeps another usable copy.

Know the recovery boundary before you import

CalcLock does not offer cloud sync, a backup-and-restore service, an export function or a forgotten-equation reset. Vault data is excluded from device backups, and the device-bound key should not be treated as something a new phone can restore for you.

Losing the device, removing the app or forgetting the equation can permanently remove access. Keep original photos outside the vault and maintain a separate, usable copy wherever your wider photo-storage plan requires one. Do not erase an old phone on the assumption that its vault will appear on a new one.

A clear routine is part of privacy

Start with a small collection whose originals you can afford to test. Verify the exact entry sequence, inspect the imported files and confirm how the app locks when you leave. Keep the sources, and review who can access any copies outside the app.

No account is required for the vault, and the app does not operate an account server, cloud-sync service or telemetry flow. Photos and Files providers can have their own permissions and network behavior outside the app's local storage. Review those separately rather than assuming that every source becomes local because the destination is.