Cubby is built on LogMeIn's own cloud data sync and storage service - not hosted on a third party cloud dataplatform - and takes advantage of the same online-banking-level encryption capabilities used in LogMeIn's connectivity offerings (like LogMeIn Free and Pro, LogMeIn Rescue and join.me).
In hybrid form, a private cloud can include data stored on premise or off, with a private Platform-as-a-Service middleware layer managing application data and enforcing data security.