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Date: Tue, 28 Aug 2012 14:21:07 -0500
From: "jfoug" <jfoug@....net>
To: <john-users@...ts.openwall.com>
Subject: RE: JtR vs. hashcat on /r/crypto (was: passwords cracked vs. time)

>From: Solar Designer [mailto:solar@...nwall.com]
>
>2. It turns out (was news to me) that hashcat added SunMD5 support
>recently (on CPU).  According to atom, it does not use SIMD, yet is
>faster than ours with SIMD (JimF's unreleased code in magnum-jumbo).
>I've asked atom for specific speed numbers, but we might want to do our
>own benchmarks as well (Jim?), if we don't mind running the closed-
>source hashcat for that. ;-)
>

I have a strong belief the coin flip logic we have (the original sun logic),
is where the speedup can be found. Yes, we did remove a %5 in one of the
loops.  But there still has to be a LOT of optimization left. There is a lot
of temp memory usage, and memory movement.  It 'could' be some other factor,
but I really think not.  This is why I was surprised by only a 3.5x
improvement when going to SSE2 code.  I expected a much higher rate, since
we modify that large buffer so little.

Possibly there is something Atom was able to find, that busted the coinflip,
and found some way to compute it in a deterministic (or nearly
deterministic) manner.

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