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| author | Milan Broz <mbroz@redhat.com> | 2011-01-13 19:59:54 +0000 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2011-01-13 19:59:54 +0000 |
| commit | d1f9642381847e2b94caa34c3533211cf36ffcf4 (patch) | |
| tree | 32ae1cc4b0946247384fe1a31e257658f734b3f7 /Documentation | |
| parent | 2dc5327d3acb3340ab6fa3981401b076b78a51f4 (diff) | |
| download | lwn-d1f9642381847e2b94caa34c3533211cf36ffcf4.tar.gz lwn-d1f9642381847e2b94caa34c3533211cf36ffcf4.zip | |
dm crypt: add multi key capability
This patch adds generic multikey handling to be used
in following patch for Loop-AES mode compatibility.
This patch extends mapping table to optional keycount and
implements generic multi-key capability.
With more keys defined the <key> string is divided into
several <keycount> sections and these are used for tfms.
The tfm is used according to sector offset
(sector 0->tfm[0], sector 1->tfm[1], sector N->tfm[N modulo keycount])
(only power of two values supported for keycount here).
Because of tfms per-cpu allocation, this mode can be take
a lot of memory on large smp systems.
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Cc: Max Vozeler <max@hinterhof.net>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/device-mapper/dm-crypt.txt | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/Documentation/device-mapper/dm-crypt.txt b/Documentation/device-mapper/dm-crypt.txt index 524de926290d..59293ac4a5d0 100644 --- a/Documentation/device-mapper/dm-crypt.txt +++ b/Documentation/device-mapper/dm-crypt.txt @@ -8,7 +8,7 @@ Parameters: <cipher> <key> <iv_offset> <device path> <offset> <cipher> Encryption cipher and an optional IV generation mode. - (In format cipher-chainmode-ivopts:ivmode). + (In format cipher[:keycount]-chainmode-ivopts:ivmode). Examples: des aes-cbc-essiv:sha256 @@ -20,6 +20,11 @@ Parameters: <cipher> <key> <iv_offset> <device path> <offset> Key used for encryption. It is encoded as a hexadecimal number. You can only use key sizes that are valid for the selected cipher. +<keycount> + Multi-key compatibility mode. You can define <keycount> keys and + then sectors are encrypted according to their offsets (sector 0 uses key0; + sector 1 uses key1 etc.). <keycount> must be a power of two. + <iv_offset> The IV offset is a sector count that is added to the sector number before creating the IV. |