From e3dcc5a387fc38e9c3c6c4f857cd9a7f71a8553a Mon Sep 17 00:00:00 2001 From: Milan Broz Date: Thu, 24 Apr 2008 22:11:03 +0100 Subject: [PATCH] dm crypt: add documentation Add description of dm-crypt to device-mapper documentation. Signed-off-by: Milan Broz Signed-off-by: Alasdair G Kergon --- Documentation/device-mapper/dm-crypt.txt | 52 ++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 Documentation/device-mapper/dm-crypt.txt diff --git a/Documentation/device-mapper/dm-crypt.txt b/Documentation/device-mapper/dm-crypt.txt new file mode 100644 index 000000000000..6680cab2c705 --- /dev/null +++ b/Documentation/device-mapper/dm-crypt.txt @@ -0,0 +1,52 @@ +dm-crypt +========= + +Device-Mapper's "crypt" target provides transparent encryption of block devices +using the kernel crypto API. + +Parameters: + + + Encryption cipher and an optional IV generation mode. + (In format cipher-chainmode-ivopts:ivmode). + Examples: + des + aes-cbc-essiv:sha256 + twofish-ecb + + /proc/crypto contains supported crypto modes + + + Key used for encryption. It is encoded as a hexadecimal number. + You can only use key sizes that are valid for the selected cipher. + + + The IV offset is a sector count that is added to the sector number + before creating the IV. + + + This is the device that is going to be used as backend and contains the + encrypted data. You can specify it as a path like /dev/xxx or a device + number :. + + + Starting sector within the device where the encrypted data begins. + +Example scripts +=============== +LUKS (Linux Unified Key Setup) is now the preferred way to set up disk +encryption with dm-crypt using the 'cryptsetup' utility, see +http://luks.endorphin.org/ + +[[ +#!/bin/sh +# Create a crypt device using dmsetup +dmsetup create crypt1 --table "0 `blockdev --getsize $1` crypt aes-cbc-essiv:sha256 babebabebabebabebabebabebabebabe 0 $1 0" +]] + +[[ +#!/bin/sh +# Create a crypt device using cryptsetup and LUKS header with default cipher +cryptsetup luksFormat $1 +cryptsetup luksOpen $1 crypt1 +]]