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1 | dm-crypt | ||
2 | ========= | ||
3 | |||
4 | Device-Mapper's "crypt" target provides transparent encryption of block devices | ||
5 | using the kernel crypto API. | ||
6 | |||
7 | Parameters: <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 | |||
35 | Example scripts | ||
36 | =============== | ||
37 | LUKS (Linux Unified Key Setup) is now the preferred way to set up disk | ||
38 | encryption with dm-crypt using the 'cryptsetup' utility, see | ||
39 | http://luks.endorphin.org/ | ||
40 | |||
41 | [[ | ||
42 | #!/bin/sh | ||
43 | # Create a crypt device using dmsetup | ||
44 | dmsetup 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 | ||
50 | cryptsetup luksFormat $1 | ||
51 | cryptsetup luksOpen $1 crypt1 | ||
52 | ]] | ||