Is there a way to encrypt a folder, which is not in /home but even in a different partition, so only my user can access/read contained files?
Alternatively, I would like to understand if it is possible to turn a complete ext4 partition into an encrypted volume, which would be mounted at user login.
If possible, I would like to make the change without reinstalling Ubuntu.

My PC has (mount output):

/dev/sda1 on / type ext4 (rw,errors=remount-ro)
/dev/sda3 on /home type ext4 (rw)
/dev/sda4 on /home/igor/Personale type ext4 (rw)

sda4 is the partition containing folders I would like to protect.

Thanks!