Before I buy such one I really need to be sure that I can have encryption on
this device. I want to use it to store my personal backup at a remote side.

Is it possible to do a rsync (with SSH) from my CentOS box to the ReadyNAS
box where I store my files on an encrypted partition or alike? Note that I
cannot encrypt the files I transfer as I do an incremental backup (with
rsync), so the source rsync must be able to see its raw files on destination
ReadyNAS.

I only see this would be possible if the RNAS box natively (or through an
addon) would be able to do some kind of secure encryption where it fx. asks
for a password once it reboots. Just like the Linux LUKS dm-crypt stuff
works.

Speed/throughput on the RNAS is not that important as it will be located
remotely anyhow.

Any insights?