The newly-released kernel v2.6.32-504.23.4.el6 includes the back-ported SHA256-SSSE3 driver. Why is the generic version of the SHA256 driver selected at runtime instead of the SSSE3 version on this x86_64 system? Yes, my CPU does support the SSSE3 instruction set, and the use of SHA256 is invoked by the LUKS "cipher=aes-cbc-essiv:sha256" option. On the running system I see that the sha256-ssse3 driver is not loaded. Further evidence that the generic driver is in use: # grep sha256 /proc/crypto name : sha256 driver : sha256-generic So... what's the trick to using the sha256-ssse3 driver instead of the generic driver? Thanks.