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Milan Broz authored
Add experimental support for BitLocker encryption with CBC mode and additional Elephant diffuser. The mode was used in older Windows systems and it is provided mainly for compatibility reasons. The userspace support to activate these devices is being added to cryptsetup utility. Read-write activation of such a device is very simple, for example: echo <password> | cryptsetup bitlkOpen bitlk_image.img test The Elephant diffuser uses two rotations in opposite direction for data (Diffuser A and B) and also XOR operation with Sector key over the sector data; Sector key is derived from additional key data. The original public documentation is available here: http://download.microsoft.com/download/0/2/3/0238acaf-d3bf-4a6d-b3d6-0a0be4bbb36e/bitlockercipher200608.pdf The dm-crypt implementation is embedded to "elephant" IV (similar to tcw IV construction). Because we cannot modify original bio data for write (before encryption), an additional internal flag to pre-process data is added. Signed-off-by:
Milan Broz <gmazyland@gmail.com> Reviewed-by:
Mikulas Patocka <mpatocka@redhat.com> Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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