In this section, we'll create a file container, you can think of it as a vault, and we encrypt whatever is put inside. As long as the vault is unlocked, files can be added to or deleted from it just like any regular filesystem, but once we lock it, no one will be able to peek inside or guess what's in the vault.
We'll be using a tool called
cryptsetup that will help us create and manage the encrypted containers. Type the following command to install cryptsetup and the optional dosfstools
if you'd like your vault to be accessible on a Windows machine:
pi@raspberrypi ~ $ sudo apt-get install cryptsetup dosfstools
This technique will give you an encrypted vault mounted under a directory. You can then add files to it as you wish, and once locked, you can copy it and open it up on Windows.
First, we need to create an empty file to hold our vault. Here you'll have to decide how much storage space to allocate to your vault....