[kwlug-disc] folder encryption

[Chris Frey]

On Thu, Sep 29, 2022 at 02:05:55PM -0400, CrankyOldBugger wrote:
> So..  what do you guys recommend for natively (i.e. inside Ubuntu) for
> creating a folder then encrypting all the contents?  Is this a doable thing
> without major headaches?

I'm a fan of cryptsetup.

	# create image file, sparse or not (don't go less than about 20M
	# due to required size of luks headers and keys)
	dd if=/dev/zero of=image.bin bs=1 count=0 seek=100M

	# encrypt it
	cryptsetup luksFormat ./image.bin

	# open it
	cryptsetup open ./image.bin image

	# fs it
	mkfs /dev/mapper/image

	# mount it... can go anywhere you need
	mount /dev/mapper/image /mnt

	# enjoy it
	cp secrets /mnt

	# unmount it
	umount /mnt

	# close it
	cryptsetup close image

Watch out for swap... if your swap partition is not encrypted, some of
your private date can end up there.

You can put things in /etc/crypttab and /etc/fstab to automate the mounting
process.  There are tools like cryptdisks_start and cryptdisks_stop.

I do this on home directories, usb backup sticks, etc.

- Chris