tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1dm-crypt
2=========
3
4Device-Mapper's "crypt" target provides transparent encryption of block devices
5using the kernel crypto API.
6
7Parameters: <cipher> <key> <iv_offset> <device path> <offset>
8
9<cipher>
10 Encryption cipher and an optional IV generation mode.
11 (In format cipher-chainmode-ivopts:ivmode).
12 Examples:
13 des
14 aes-cbc-essiv:sha256
15 twofish-ecb
16
17 /proc/crypto contains supported crypto modes
18
19<key>
20 Key used for encryption. It is encoded as a hexadecimal number.
21 You can only use key sizes that are valid for the selected cipher.
22
23<iv_offset>
24 The IV offset is a sector count that is added to the sector number
25 before creating the IV.
26
27<device path>
28 This is the device that is going to be used as backend and contains the
29 encrypted data. You can specify it as a path like /dev/xxx or a device
30 number <major>:<minor>.
31
32<offset>
33 Starting sector within the device where the encrypted data begins.
34
35Example scripts
36===============
37LUKS (Linux Unified Key Setup) is now the preferred way to set up disk
38encryption with dm-crypt using the 'cryptsetup' utility, see
39http://luks.endorphin.org/
40
41[[
42#!/bin/sh
43# Create a crypt device using dmsetup
44dmsetup create crypt1 --table "0 `blockdev --getsize $1` crypt aes-cbc-essiv:sha256 babebabebabebabebabebabebabebabe 0 $1 0"
45]]
46
47[[
48#!/bin/sh
49# Create a crypt device using cryptsetup and LUKS header with default cipher
50cryptsetup luksFormat $1
51cryptsetup luksOpen $1 crypt1
52]]