Messages in this thread | | | Date | Sun, 3 Oct 2004 19:15:45 -0700 (PDT) | From | dean gaudet <> | Subject | Re: [PATCH] AES x86-64-asm impl. |
| |
On Sat, 2 Oct 2004, Andi Kleen wrote:
> Unfortunately it's still fundamentally 32bit. Anybody interested > in doing a true 64bit AES?
i doubt it helps any -- except for benchmark-only purposes.
there's a description of the 32-bit T-table approach in section 7.3 of <http://fp.gladman.plus.com/cryptography_technology/rijndael/aesspec.pdf>
basically the tables are 8-bit -> 32-bit maps, and there are 4 of them (2 for each direction). to go to 64-bit you'd need 16-bit -> 64-bit maps... 512KiB per table. there are some other variations on the tables which are smaller, but nothing as small as the 1024 bytes per table of the 32-bit implementation.
there's a completely different approach using bit-slicing (basically consider each register as 64 1-bit registers), which yields great throughput but cruddy latency -- you basically need lots of non-dependant streams to make this pay off (i.e. it might work for disk crypto processing multiple blocks simultaneously).
-dean - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |