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Message-ID: <1f3b4086fb7e668a31eb493e70b0a625@smtp.hushmail.com>
Date: Mon, 13 May 2013 20:42:06 +0200
From: magnum <john.magnum@...hmail.com>
To: john-dev@...ts.openwall.com
Subject: Re: Incremental mode in 1.7.9.14
On 13 May, 2013, at 20:22 , Solar Designer <solar@...nwall.com> wrote:
> On Mon, May 13, 2013 at 07:30:44PM +0200, magnum wrote:
>> I had similar results with two-character candidates and so on. Is there any way short lengths could get more "weight", or some other mitigation for this "regression"?
>
> They get so little weight because they're so rare in the training set
> (perhaps non-existent, for these specific characters?) However, you may
> adjust their weight here in charset.c:
>
> est *= (*cracks)[length][pos][count];
> if (est < 1e-3) /* may adjust this */
> est = 1e-3;
>
> Change the 1e-3 (in both places) to something larger (e.g., 1e-2).
> I think the largest value that makes sense is 1.0. So maybe test these:
>
> 0.01
> 0.1
> 0.5
> 0.9
> 1.0
>
> ... and you've already tested 0.001 and are unhappy with it. In your
> testing, also see how this affects efficiency (in terms of successful
> guesses per candidates tested) for actual runs (e.g. train on one half
> of RockYou, test on the other, or train on RockYou and test on another
> real-world data set). I suspect that as results "improve" in terms of
> uncommon short strings being tried sooner, they will be getting worse in
> terms of efficiency. I understand that we do need to be testing really
> short strings reasonably early anyway, though.
Thanks, I will try this. So if I understand the old code & comments, 1.7.9 used 1.0 for this, right?
Just thinking out loud, how about using some variant of "1/length" instead of a fixed figure? That would benefit really short lengths but not skew the longer ones.
magnum
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