GF(2^128) multiplication tables are typically used for secret
information, so it's a good idea to zero them on free.
Signed-off-by: Alex Cope <alexcope@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This code is unlikely to be useful in the future because transforms
don't know how often keys will be changed, new algorithms are unlikely
to use lle representation, and tables should be replaced with
carryless multiplication instructions when available.
Signed-off-by: Alex Cope <alexcope@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In gf128mul_lle() and gf128mul_bbe() r isn't completely initialized with
zero because the size argument passed to memset() is the size of the
pointer, not the structure it points to.
Luckily there are no in-kernel users of those functions so the ABI
change implied by this fix should break no existing code.
Based on a patch by the PaX Team.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: PaX Team <pageexec@freemail.hu>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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>
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>
Alex Cope
Mathias Krause
Lucas De Marchi
Adrian-Ken Rueegsegger
Rik Snel