[CRYPTO] lib: table driven multiplications in GF(2^128)
A lot of cypher modes need multiplications in GF(2^128). LRW, ABL, GCM...
I use functions from this library in my LRW implementation and I will
also use them in my ABL (Arbitrary Block Length, an unencumbered (correct
me if I am wrong, wide block cipher mode).
Elements of GF(2^128) must be presented as u128 *, it encourages automatic
and proper alignment.
The library contains support for two different representations of GF(2^128),
see the comment in gf128mul.h. There different levels of optimization
(memory/speed tradeoff).
The code is based on work by Dr Brian Gladman. Notable changes:
- deletion of two optimization modes
- change from u32 to u64 for faster handling on 64bit machines
- support for 'bbe' representation in addition to the, already implemented,
'lle' representation.
- move 'inline void' functions from header to 'static void' in the
source file
- update to use the linux coding style conventions
The original can be found at:
http://fp.gladman.plus.com/AES/modes.vc8.19-06-06.zip
The copyright (and GPL statement) of the original author is preserved.
Signed-off-by: Rik Snel <rsnel@cube.dyndns.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/Kconfig b/crypto/Kconfig
index 4495e46..f941ffb 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -139,6 +139,16 @@
See also:
<http://www.cs.technion.ac.il/~biham/Reports/Tiger/>.
+config CRYPTO_GF128MUL
+ tristate "GF(2^128) multiplication functions (EXPERIMENTAL)"
+ depends on EXPERIMENTAL
+ help
+ Efficient table driven implementation of multiplications in the
+ field GF(2^128). This is needed by some cypher modes. This
+ option will be selected automatically if you select such a
+ cipher mode. Only select this option by hand if you expect to load
+ an external module that requires these functions.
+
config CRYPTO_ECB
tristate "ECB support"
select CRYPTO_BLKCIPHER