There are a ton of third party tools for windows that map an encrypted image file to a drive letter (such as Cryptainer LE) so I figured I’d go look around to see how to do it in linux.
http://www.saout.de/tikiwiki/tiki-index.php?page=looptutorial has a great tutorial on how to set this up, but here’s a quick listing of all the commands for the imaptient:
Create and mount an image file
dd if=/dev/zero of=crypt.img bs=1k count=51200 sudo losetup /dev/loop0 crypt.img sudo cryptsetup -h ripemd160 -c twofish create crypt /dev/loop0 sudo mkreiserfs /dev/mapper/crypt sudo mount -t reiserfs /dev/mapper/crypt /mnt/moo
This creates a 50MB file, to change this set count to the desired size in kilobytes.
Unmount the image file
sudo umount /mnt/moo sudo cryptsetup remove crypt sudo losetup -d /dev/loop0
Remount the image file (For example, after rebooting)
sudo losetup /dev/loop0 crypt.img sudo cryptsetup -h ripemd160 -c twofish create crypt /dev/loop0 sudo mount -t reiserfs /dev/mapper/crypt /mnt/moo
When you remount cryptsetup will not tell you if the password you entered is the same as the password entered preveously, so if the mount fails you probabally mistyped it. Be carefull because if you write to the image using a different private key (password) you will erase everything in it!