[Botan-devel] [Updated] RSA, DES on x86-64 (was Re: RSA, DSA in Botan and OpenSSL on x86-64)

Jack Lloyd lloyd at randombit.net
Fri Oct 17 09:29:11 EDT 2008


On Fri, Oct 17, 2008 at 09:22:05AM -0400, Jack Lloyd wrote:
> below, and keep in mind OpenSSL's numbers are in 1000s of bytes, Botan
> uses 2^20. Which if I did the math right means (at least on my
> personal desktop machine, YMMV and probably will, and I haven't
> checked this result on any other machine), 3DES in Botan is at least

On a POWER5+ (hazelnut.osuosl.org), OpenSSL's 3DES is showing up 30%
faster (and I bet if I swapped in the bit ops sequence, Botan would
catch up quite a bit, though not match it.)

Probably need to make this a build option/optimization, then, and take
a magic IP/FP bit op sequence from a public domain DES.

I really had expected a 8-core POWER5+ would have the memory bandwidth
for this table IP/FP trick to be effective, so this is a little
surprising/disconcerting. (Or maybe this just means I don't understand
RAM performance characteristics as well as I thought - this is more
likely)

BTW, I will not be checking email again until Tuesday night (2008-10-21)

-Jack



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