Installing necessary tools
sudo apt-get install aespipe mkisofs loop-aes-utils
Chose a password
You need to chose a 20+ character password and DO NOT FORGET IT, you will NEVER get your data back if you forget the password.
Creating the CD/DVD image
Make a directory called backup then copy the files you want to burn into the backup directory.
We are using AES encryption, you can chose from 128 or 256 bit key lengths, I recommend 256.
mkisofs -r backup | aespipe -e aes256 > backup.iso
or for 128 bit key length
mkisofs -r backup | aespipe -e aes128 > backup.iso
Mounting the image
First we need to load some modules
sudo modprobe aes
sudo modprobe cryptoloop
For 128 bit key lengths:
sudo mount -t iso9660 backup.iso /mnt/iso -o loop=/dev/loop0,encryption=aes128
For 256 bit key lengths:
sudo mount -t iso9660 backup.iso /mnt/iso -o loop=/dev/loop0,encryption=aes256
This will mount the image in /mnt/iso (make sure you have the directory before you try to mount)
You can burn the image with your favorite program (gnomebaker, k3b), you might get some warnings about the image but you can ignore them.
Mounting the new CD/DVD
First make sure you loaded the aes and cryptoloop modules (see above)
sudo mount -t iso9660 /dev/cdrom /mnt/iso -o loop=/dev/loop0,encryption=aes256