I have an external USB hard drive that I would like to use as a backup.
My "old" Maxtor usb/firewire is very fast and usefull, but it is not encrypted.

My idea is to use the dm-crypt and cryptsetup/Luks and make a ext3 partition mount only with password.
This would be suficient for protecting data.

Does anyone tried this before?
How is the beahviour of the USB drive when mounting after the encryption process. Does it automount and asks for the password?
Or it as to be done manually with luksOpen ?