SecretLocker app does not collect any of your data.

SecretLocker app does not share any of your data.

SecretLocker app does not store any of your data on your device except the encryption key when you click Save.

The encryption key is stored in encrypted way into app's native storage (Keychain on iOS or Keystore on Android )
To delete the encryption key from your device : open Key editor popup dialog, clear the key field, click Save.