Encrypted external storage
If, for whatever reason, you'd like to have an external storage device - be it a pen-drive, an SD card, a hard disk - to be secure, you can easily encrypt it. The procedure is pretty straightforward.
The procedure outlined assumes you are using a Debian GNU/Linux system, but should be very similar on other Linux distributions.
Prepare the device
Install the needed tools:
#> apt-get install cryptsetup
Format the external device and create the file system (replace
with your actual device name).
#> cryptsetup -y -v luksFormat /dev/sdx #> cryptsetup luksOpen /dev/sdx EXT #> dd if=/dev/zero of=/dev/mapper/EXT status=progress #> mkfs.ext4 /dev/mapper/EXT #> cryptsetup luksClose EXT
Use the device
To mount the encrypted device:
#> cryptsetup luksOpen /dev/sdx EXT #> mount /dev/mapper/EXT /mnt
To unmount it:
#> umont /mnt #> cryptsetup luksClose EXT