Cryptsetup Operations
Internal
Overview
cryptsetup is the userspace utility used to manage the dm-crypt encryption functionality.
Installation
yum install cryptsetup
Creating an Encrypting a Block Device with cryptsetup/LUKS
Overview
This section describes how to create a passphrase-protected LUKS-encrypted block device, expose it under /dev/mapper under an arbitrary name, then build an XFS file system on it, and then mount it.
Procedure
Format the block device with LUKS and assign it a passphrase (it is also possible to use a key file). The command will ask for a passphrase at the console:
cryptsetup luksFormat -y -v /dev/sdb
Test password: b4H4x9_3hdHEd
After 'luksFormat' operation, the block device is now type "", as blkid shows:
# blkid ... /dev/sdb: UUID="8a5fa3ae-d997-4c3a-a6f6-ab7ac9007ef8" TYPE="crypto_LUKS"
Open the crypto_LUKS device with:
cryptsetup open <luks-device> <mapping-name>
where <mapping-name> is the name of the device that will be created under /dev/mapper:
cryptsetup open /dev/sdb rackstationb
Upon providing the correct passphrase, the encrypted device will be mounted as /dev/mapper/rackstationb:
cd /dev/mapper/ ls -al rackstationb lrwxrwxrwx. 1 root root 7 Dec 24 00:36 rackstationb -> ../dm-2
Once the encrypted device is available under /dev/mapper, a filesystem can be built on it:
mkfs.xfs /dev/mapper/rackstationb
The filesystem can then be mounted and used:
mount /dev/mapper/rackstationb /rackstationb
Closing a LUKS Device
umount /dev/mapper/<mapping-name> cryptsetup close /dev/mapper/<mapping-name>
Mounting a LUKS Device at Boot
Overview
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