eCryptfs is a kernel-native cryptographic filesystem. It’s also a stacked filesystem, which means that eCryptfs must work on top of another filesystem such as Ext3. The result of this is that you don’t need to allocate space for eCryptfs, it will grow and shrink as you add files to it.
Install eCryptfs from the package ecryptfs-utils by running the command below in your terminal:
apt-get install ecryptfs-utils
Create a new directory to encrypt. In this case I used a directory called Private in my home folder:
If you don’t want other users on your system snooping on your Private directory, change its permissions to deny anyone but your user access:
chmod 700 ~/Private
Now, mount a new eCryptfs filesystem in your new folder:
mount -t ecryptfs ~/Private ~/Private
You’ll be asked some questions by eCryptfs configuration. I selected to use a passphrase, the default AES encryption, and 32-byte key length. Notice the defaults, indicated in square brackets, if you’re not sure about an option. eCryptfs will notice that this is the first time you have used your passphrase, and will ask if it can save a hash so it doesn’t have to warn you every time.
and go to complete the mount:
Now, to test the encryption, go to the Private directory, create a file and umount the ~/Private directory.
The Private encrypted directory is umounted now.. try to read the file.
Now, remount the partition and take a look in encrypted directory.