Use Intel AES-NI instructions for AES algorithm.

AES cipher algorithms (FIPS-197). AES uses the Rijndael
algorithm.

Rijndael appears to be consistently a very good performer in
both hardware and software across a wide range of computing
environments regardless of its use in feedback or non-feedback
modes. Its key setup time is excellent, and its key agility is
good. Rijndael's very low memory requirements make it very well
suited for restricted-space environments, in which it also
demonstrates excellent performance. Rijndael's operations are
among the easiest to defend against power and timing attacks.

The AES specifies three key sizes: 128, 192 and 256 bits

See <http://csrc.nist.gov/encryption/aes/> for more information.

In addition to AES cipher algorithm support, the acceleration
for some popular block cipher mode is supported too, including
ECB, CBC, LRW, XTS. The 64 bit version has additional
acceleration for CTR.

source code:

arch/x86/crypto/