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Date: Fri, 29 Jun 2012 23:43:50 +0200
From: Frank Dittrich <frank_dittrich@...mail.com>
To: john-dev@...ts.openwall.com
Subject: Re: For some dynamic formats on linux-x86-mmx build cracking
 depends on password candidate sequence

On 06/29/2012 11:32 PM, Frank Dittrich wrote:
> But
> $ grep -n "^swordfish$" pw.dic
> 5762:swordfish
> $ grep -n "^asdfasfga__7$" pw.dic
> 5122:asdfasfga__7
> $ grep -n "^characters__5$" pw.dic
> 5250:characters__5
> 
> 
> 5762 = 45 * 128 + 2
> 5122 = 40 * 128 + 2
> 5250 = 41 * 128 + 2
> 
> So, for the clang build not just the first candidate password of a new
> 128 passwords block is affected, but the first two passwords.

Sometimes I give up too early:

$ grep -n "^PIII__4$" pw.dic
5378:PIII__4
$ grep -n "^pentium__4$" pw.dic
5379:pentium__4

5379 = 42 * 128 + 3

So, looks like (at least) the first 4 candidate passwords of a new
MAX_KEYS_PER_CRYPT block can be affected for the clang build.

(I can try to shuffle passwords around, to see if they are always
affected. Or I could just check at which lines those passwords cracked
in the first run were located.
But that will be sometime next week, unless someone found the bug by
that time.)

And, of course, the workaround code change posted for dynamic_2 earlier
in this thread works as well. But that costs 2.5 - 3 % performance for
my 32 bit linux-x86 builds.

Frank

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