EncFS is an encrypted filesystem based on FUSE. It transparently encrypts files stored in it and places them on another volume. This is in contrast to block level encrypted filesystems which transparently encrypt the data under the filesystem layer as it is being written to disk. Think of EncFS as a bind mount, except that the source for the mount is encrypted and the place it is mounted to is the only place it is available unencrypted.
The main advantage of EncFS filesystems is that when backing up only the files which have changed need to be backed up. This means it works perfectly with tools such as rsnapshot. Another advantage is that the filesystem doesn’t need a block of disk allocated to it and will shrink and expand as the files inside change.
Finally because this is all implemented with FUSE it is all done in userspace. No root access is required (apart from setting FUSE up) to create and alter encfs filesystems.
Setting Up an EncFS Volume
So the first thing you need to do to setup an encfs volume is to install FUSE and EncFS. If you don’t have root access you will have to ask your sysadmin to do this for you, otherwise follow your distribution specific method of installing new packages. On Fedora it is called ‘fuse-encfs’ and on Debian/Ubuntu its called ‘encfs’. On some older systems users wishing to use FUSE may need to be added to the correct group.
First you need to decide where you will put the encfs volume, and where you’ll mount it. I usually put mine in /home/daniel/.crypt and mount it to /home/daniel/crypt. But feel free to name it whetever you want. When you’ve decided run the EncFS with those arguments, for example to use the example I specified it would look like this:
<daniel@server ~>$ encfs /home/daniel/.crypt /home/daniel/crypt The directory "/home/daniel/.crypt/" does not exist. Should it be created? (y,n) y The directory "/home/daniel/crypt" does not exist. Should it be created? (y,n) y Creating new encrypted volume. Please choose from one of the following options: enter "x" for expert configuration mode, enter "p" for pre-configured paranoia mode, anything else, or an empty line will select standard mode. ?> Standard configuration selected. Configuration finished. The filesystem to be created has the following properties: Filesystem cipher: "ssl/aes", version 2:2:1 Filename encoding: "nameio/block", version 3:0:1 Key Size: 192 bits Block Size: 1024 bytes Each file contains 8 byte header with unique IV data. Filenames encoded using IV chaining mode. File holes passed through to ciphertext. Now you will need to enter a password for your filesystem. You will need to remember this password, as there is absolutely no recovery mechanism. However, the password can be changed later using encfsctl. New Encfs Password: Verify Encfs Password:
As you can see the directories don’t need to be created first. There is also a prompt for what security settings you want to use. Hitting enter will give you standard settings, but for something more powerful you should hit ‘p’ then enter. You can now proceed to place files in /home/daniel/crypt and they will be encrypted and placed into /home/daniel/.crypt. If you don’t believe me go ahead and check.
See? I told you so. Now you can unmount it using ‘fusermount -u /home/daniel/crypt’ and mount it again using encfs /home/daniel/.crypt /home/daniel/crypt and typing your password.
Random Thought: When travelling to other countries, local laws may mean that customs can search your laptop, including encrypted filesystems. You may have to reveal your key, or be arrested.