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user308393
Asked: 2014-07-24 08:19:45 +0800 CST

Can I "cryptsetup ... luksFormat" a partition formatted with Ext4, or must it be unformatted?

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I would like to setup Full Disk Encryption (FDE) for an external harddrive. My question is about the sequence of formatting. Will the following sequence work fine or do I need to run luksFormat on an unformatted partition?

  1. use gparted to create an msdos partition-table
  2. use gparted to create and format a partition with Ext4 (let's say partition name is "sdb1")
  3. unmount partition /dev/sdb1
  4. open Terminal and run command sudo cryptsetup luksFormat /dev/sdb1

Do I now have an FDE external harddrive? I've read in a few places that the luksFormat command is run on an unformatted partition. Is this a requirement? Have I done anything wrong by formatting with Ext4 and then running luksFormat? Any guidance on how to properly achieve FDE for external harddrive would be great. Thanks.

performing this task on Ubuntu 14.04.

luks

1 Answers

  1. Best Answer

    You have the order wrong. Assuming sdb1 ...

    sudo dd if=/dev/urandom of=/dev/sdb1
sudo cryptsetup -y -v luksFormat /dev/sdb1
sudo cryptsetup luksOpen /dev/sdb1 $name #change "$name" to any name you wish
# now format
sudo mkfs.ext4 /dev/mapper/$name
sudo mkdir /media/mount_point
sudo mount /dev/mapper/$name /media/mount_point

    See:

    http://www.cyberciti.biz/hardware/howto-linux-hard-disk-encryption-with-luks-cryptsetup-command/

    https://help.ubuntu.com/community/EncryptedFilesystemHowto3

    https://wiki.archlinux.org/index.php/Dm-crypt

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