On Linux ZFS has has an encryption feature developed by datto.com. They developed this feature for their own hosted encrypted backup service. If you have you

On Linux ZFS has has an encryption feature developed by datto.com. They developed this feature for their own hosted encrypted backup service. If you have you data encryped in ZFS like that locally, you can use zfs send to send them encrypted snapshots of your data while only ever having to transmit the diffs. I am in the process of setting up something like this with my own backup server right now. I'm not 100 % confident yet that I'll get it working though. Have you looked into tarsnap.com?