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Date: Thu, 7 Jun 2012 09:17:21 +0200
From: Frank Dittrich <frank_dittrich@...mail.com>
To: john-dev@...ts.openwall.com
Subject: Re: get_source() and bitmaps boost

On 06/07/2012 01:44 AM, magnum wrote:
> I got the idea to use the 6.5 million leaked hashes for some speed &
> memory tests. All tests consist of running --incremental=digits to
> completion, with all those candidates already cracked (so crack prints
> does not slow things down).

Which hardware and which build target did you use?
(I assume you are using a recent x86_64 ubuntu. Am I right?)
How much memory does the system have?

> Memory usage (RSS peak):
> magnum-jumbo: 875 MB
> magnum-jumbo w/ get_source added: 530 MB
> bleeding-jumbo: 674 MB
> bleeding-jumbo w/ get_source reverted: 1 GB
> 
> Bleeding is 43% faster than magnum-jumbo because of these two changes,
> mostly because of the bitmaps. One way to put it is that the get_source
> patch regains all memory the bitmaps use, and much more. And it boosts
> bleeding-jumbo by another 6%.

This also means, that you probably could use a password list that is
about 1.6 times the size that can be used with magnum-jumbo, if you
apply the get_source patch.
(Memory usage is about 1.65 times as high without the patch, but for the
attack (wordlist / incremental / ...) you'll also need some memory.)

So, for the 145 million md5 hashes released by Korelogic, you can use
much larger (and that's why: fewer) chunks.
(This is not surprising, since these 145 million hashes inspired the
code changes in the first place.)

Interesting improvements.

On which platforms did you run the test suite for magnum-jumbo with the
get_source patch applied and for bleeding-jumbo?
Which platforms need to be tested?

What other tests could help finding any hidden bugs?
(Running real cracking sessions against "real" hashes, and compare the
results? What else?)

Frank

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