[CRYPTO] xts: XTS blockcipher mode implementation without partial blocks

XTS currently considered to be the successor of the LRW mode by the IEEE1619
workgroup. LRW was discarded, because it was not secure if the encyption key
itself is encrypted with LRW.

XTS does not have this problem. The implementation is pretty straightforward,
a new function was added to gf128mul to handle GF(128) elements in ble format.
Four testvectors from the specification
	http://grouper.ieee.org/groups/1619/email/pdf00086.pdf
were added, and they verify on my system.

Signed-off-by: Rik Snel <rsnel@cube.dyndns.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 11 insertions, 0 deletions

diff --git a/crypto/Kconfig b/crypto/Kconfig
index 05f46dfdf185..083d2e1dfc21 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -184,6 +184,17 @@ config CRYPTO_LRW
           The first 128, 192 or 256 bits in the key are used for AES and the
           rest is used to tie each cipher block to its logical position.
 
+config CRYPTO_XTS
+        tristate "XTS support (EXPERIMENTAL)"
+        depends on EXPERIMENTAL
+        select CRYPTO_BLKCIPHER
+        select CRYPTO_MANAGER
+        select CRYPTO_GF128MUL
+        help
+          XTS: IEEE1619/D16 narrow block cipher use with aes-xts-plain,
+          key size 256, 384 or 512 bits. This implementation currently
+          can't handle a sectorsize which is not a multiple of 16 bytes.
+
 config CRYPTO_CRYPTD
         tristate "Software async crypto daemon"
         select CRYPTO_ABLKCIPHER