US Patent 9842062 Backup accessible by subset of related devices

Some embodiments provide, for a particular device in a set of related devices, a method for backing up data synchronized between the devices. The method receives a command to create a backup for a subset of data synchronized between a subset of the devices, which is a subset of all data synchronized between the devices. The method identifies the subset of synchronization data from the set of all synchronization data. The subset of synchronization data is tagged as pertaining to a particular set of criteria for synchronization between only the subset of devices. The method stores a backup of the subset of synchronization data in a backup storage encrypted in such a way that requires a recovery key associated with any one of the devices in the subset of devices to access the backup while preventing access to the backup with recovery keys of any of the other devices.