dm-crypt

zh-CN:System Encryption with LUKS

Related articles

• Disk Encryption
• Removing System Encryption
• Plain dm-crypt without LUKS

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:

• Preparation of the drive(s) where the system will be installed
• Creation of the needed encryption layers
• Configuration of the system to handle the encryption
• Installation of the system following the Installation Guide or the Beginners' Guide

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

See Dm-crypt/Encrypting a non-root file system and Dm-crypt/Encrypting an entire system.

Drive preparation

This step will deal with operations like securely erasing the drive and partitioning it. See Dm-crypt/Drive Preparation.

Device encryption

See Dm-crypt/Device Encryption.

System configuration

See Dm-crypt/System Configuration.

Examples

See Dm-crypt/Examples.

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.