05 Feb 10 Linux LUKS Crypt HOWTO

Linux kernels now support encrypted filesystems. Setting one up should take 5 minutes, or 3 hours if you’re like me and can’t read.

Firstly, install the right tools: apt-get install cryptsetup

Make a new partition, and initialize it with: cryptsetup luksFormat /dev/sda3 mycrypto

Where /dev/sda3 is your newly created partition and ‘mycrypto’ is your name for the container.

You will be prompted to type YES in uppercase to confirm your understanding that your partition is about to be wiped. If, like me, you type ‘yes’ in lowercase, it will fail with “Command Failed.”. You’ll then spend hours checking for loaded kernel modules, log files, and trawling google for more information. The answer is to type ‘YES’ in uppercase as you’re told

Enter a passphrase, and you’re ready to go.

Next, ‘open’ the container. cryptsetup luksOpen /dev/sdb3 enter the passphrase, and you should at this point end up with a /dev/mapper/mycrypto

Format with your desired partition mkfs.ext3 /dev/mapper/mycrypto

Then, you can mount /dev/mapper/mycrypto as you would any other block device: mount /dev/mapper/mycrypto /mnt/my_mount_point

To close the container:
umount /dev/mapper/mycrypto
cryptsetup luksClose mycrypto

Easy

Tags: crypto, cryptsetup, Linux, luks, mount, umount