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Date: Wed, 17 May 2006 04:00:35 +0400
From: Solar Designer <solar@...nwall.com>
To: john-users@...ts.openwall.com
Subject: Re: Generate chr file from finite character set

On Tue, May 16, 2006 at 02:13:44AM +0000, net sec wrote:
> Sorry for the newbie question but how would I go about creating a chr file 
> from a list of finite ASCII characters.  (example alpha plus 
> !@...^&*()-_+=) ?
> 
> I see that I can define an incremental mode section but from the 
> description, it appears that if I added an 'Extras' section for the purpose 
> of the additional characters it would treat the additional chars with less 
> frequency and I want each to have the same weight.

That's correct.

The primary advantage behind "incremental" mode is that it orders
candidate passwords for decreasing estimated probability.  It might not
be wise for you to override that.  However, you can do so by generating
a .chr file from a fake john.pot file containing lines like:

:a
:b
...
:z
:!
:@

My advice remains for you to use the supplied .chr files rather than
generate custom ones - unless you have a very good reason for doing
things differently.

This topic was discussed in here before, so you could want to check out
these other postings:

	http://thread.gmane.org/gmane.comp.security.openwall.john.user/348/focus=376
	http://thread.gmane.org/gmane.comp.security.openwall.john.user/345/focus=357

You could also look into using external mode instead of or along with
"incremental" mode:

	http://article.gmane.org/gmane.comp.security.openwall.john.user/414
	http://article.gmane.org/gmane.comp.security.openwall.john.user/603

-- 
Alexander Peslyak <solar at openwall.com>
GPG key ID: B35D3598  fp: 6429 0D7E F130 C13E C929  6447 73C3 A290 B35D 3598
http://www.openwall.com - bringing security into open computing environments

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