Following by the ecosystem of apple, as the cloud storage of your data we have chosen cloud data iCloud.
In this cloud stored backups of device , as well as in the future will be used to exchange information with POS devices (tablets at your POS).
You can be sure that we do not have access to your data, because registration data iCloud you make in the device, but not in the application.
We will not stop only on iCloud. In the future, there is support for such a cloud data as Google Drive, DropBox ...