Add hardware accelerated version of POLYVAL for x86-64 CPUs with
PCLMULQDQ support.
This implementation is accelerated using PCLMULQDQ instructions to
perform the finite field computations. For added efficiency, 8 blocks
of the message are processed simultaneously by precomputing the first
8 powers of the key.
Schoolbook multiplication is used instead of Karatsuba multiplication
because it was found to be slightly faster on x86-64 machines.
Montgomery reduction must be used instead of Barrett reduction due to
the difference in modulus between POLYVAL's field and other finite
fields.
More information on POLYVAL can be found in the HCTR2 paper:
"Length-preserving encryption with HCTR2":
https://eprint.iacr.org/2021/1441.pdf
Signed-off-by: Nathan Huckleberry <nhuck@google.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Add support for POLYVAL, an ε-Δ-universal hash function similar to
GHASH. This patch only uses POLYVAL as a component to implement HCTR2
mode. It should be noted that POLYVAL was originally specified for use
in AES-GCM-SIV (RFC 8452), but the kernel does not currently support
this mode.
POLYVAL is implemented as an shash algorithm. The implementation is
modified from ghash-generic.c.
For more information on POLYVAL see:
Length-preserving encryption with HCTR2:
https://eprint.iacr.org/2021/1441.pdf
AES-GCM-SIV: Nonce Misuse-Resistant Authenticated Encryption:
https://datatracker.ietf.org/doc/html/rfc8452
Signed-off-by: Nathan Huckleberry <nhuck@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
