john-users - Re: maximum settings for CHARSET_LENGTH and CHARSET

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Date: Thu, 8 Dec 2011 03:35:28 +0400
From: Solar Designer <solar@...nwall.com>
To: john-users@...ts.openwall.com
Subject: Re: maximum settings for CHARSET_LENGTH and CHARSET_SCALE

On Wed, Dec 07, 2011 at 11:55:05PM +0100, websiteaccess@...il.com wrote:
>  I want crack password up to 26 letters (lower) and digits (0-9)
>  In the params.h source file,  what is the maximum value for :
> 
> #define CHARSET_MIN			'0' <-- zero
> #define CHARSET_MAX		'z'
> #define CHARSET_SIZE		(CHARSET_MAX - CHARSET_MIN + 1)
> #define CHARSET_LENGTH		26   <--- I can compile with these value, but I can't generate a charset (Self test failed (pow64of32() overflow)
> #define CHARSET_SCALE		36   <--- I can compile with these value (Self test failed (pow64of32() overflow), is 36 too high or not enough ???

For versions up to 1.7.8-jumbo-8 inclusive, the maximum is:

#define CHARSET_MIN                     '0'
#define CHARSET_MAX                     'z'
#define CHARSET_SIZE                    (CHARSET_MAX - CHARSET_MIN + 1)
#define CHARSET_LENGTH                  10
#define CHARSET_SCALE                   26

That is, you can only go up to length 10 with this charset.  For version
1.7.9 (and for 1.7.9-jumbo when we release it), there's practically no
maximum for CHARSET_LENGTH (any sane value will do - e.g., 16), and
there's no CHARSET_SCALE.  I understand that for hash types you're
typically cracking you need -jumbo, so either use the settings above
(lengths up to 10) or wait for 1.7.9-jumbo.  Well, or use these settings
for now and use a larger CHARSET_LENGTH once you upgrade to 1.7.9-jumbo.

Alexander