dm-crypt

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Notes: This article is a work in progress: for its latest stable revision see Dm-crypt with LUKS. (Discuss in Talk:Dm-crypt#)

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Reason: The introduction has to be rewritten after merging Plain dm-crypt without LUKS.
Before publishing the new article, double check all the link#fragments among the subpages. (Discuss in Talk:Dm-crypt#)

This article focuses on how to set up full system encryption on Arch Linux, using dm-crypt with LUKS.

dm-crypt is the standard device-mapper encryption functionality provided by the Linux kernel. It can be used directly by those who like to have full control over all aspects of partition and key management.

LUKS is an additional convenience layer which stores all of the needed setup information for dm-crypt on the disk itself and abstracts partition and key management in an attempt to improve ease of use.

For more details on how dm-crypt+LUKS compares to other disk encryption solution, see Disk Encryption#Comparison table.

Overview

Warning: Encrypting a disk or partition will erase everything currently on that disk or partition, make appropriate data backups prior to starting.

Also be aware that encrypting a system might not only make the life of laptop thieves more miserable, but also yours if you don't plan ahead on:

  • how to make secure backups of the encrypted system/-setup/data and
  • how to access the encrypted system manually for maintenance.
Keeping those points in mind while deciding on how to use encryption may help to decide on method and tools as well.

The installation of a LUKS-encrypted system is largely the same as installing an unencrypted system. Routine creation of an encrypted system follows these general steps:

Note that the Arch installation media comes with all the tools required for system encryption.

Tip: You may want to practise encrypting a virtual hard drive in a virtual machine when learning.

Common scenarios

You should use this section as the starting point for using dm-crypt: all the needed sections of the other subpages will be appropriately linked where needed.

See Dm-crypt/Encrypting a Non-Root File System if you need to encrypt a device that is not used for booting a system, like a partition or a loop device.

See Dm-crypt/Encrypting an entire system if you want to encrypt an entire system, in particular a root partition: several scenarios are covered, including the use of LUKS headers, plain encryption, systems on LVM and RAID.

Drive preparation

This step will deal with operations like securely erasing the drive and partitioning it.

See Dm-crypt/Drive Preparation.

Device encryption

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Reason: Add some introductory text with links to the most important subsections of Dm-crypt/Device Encryption. (Discuss in Talk:Dm-crypt#)

See Dm-crypt/Device Encryption.

System configuration

Tango-view-fullscreen.pngThis article or section needs expansion.Tango-view-fullscreen.png

Reason: Add some introductory text with links to the most important subsections of Dm-crypt/System Configuration. (Discuss in Talk:Dm-crypt#)

See Dm-crypt/System Configuration.

Swap device encryption

A swap partition may be added to an encrypted system, if required. The swap partition must be encrypted as well to protect any data swapped out by the system. This part details methods without and with suspend-to-disk support.

See Dm-crypt/Swap Encryption.

Specialties

This part deals with special operations like securing the unencrypted boot partition, using GPG or OpenSSL encrypted keyfiles, a method to boot and unlock via the network, or setting up discard/TRIM for a SSD.

See Dm-crypt/Specialties.

See also

  • cryptsetup FAQ - The main and foremost help resource, directly from the developers.
  • FreeOTFE - Supports unlocking LUKS encrypted volumes in Microsoft Windows.