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Date: Sun, 19 Mar 2006 22:07:12 +0300
From: Solar Designer <>
Subject: Re: rules help

On Sun, Mar 19, 2006 at 08:46:24PM +0200, O??uz Yar??mtepe wrote:
> Hi. I didnt undestand the rules exactly. 
> In signle mode lets say i want to check 123456
> How can i write it as a rule?

You don't.  This example has nothing to do with rules, and it has
nothing to do with "single crack" mode.

If you want "123456" tried as a candidate password, you simply make sure
that it is present in your wordlist - and you run the wordlist mode (or
batch mode).

> What does <- means?

I'm not sure I understand what you're referring to here.  If you're
asking what the two characters "<-" mean in a rule, then the meaning is
to reject "words" being processed if they're shorter than the maximum
supported password length for the current hash type by more than 2
characters.  The "<" command is defined as follows (quoting doc/RULES):

<N	reject the word unless it is less than N characters long

Character position and length codes (such as N in the above command) are
specified as:

0...9	for 0...9
A...Z	for 10...35
*	for max_length
-	for (max_length - 1)
+	for (max_length + 1)

Here max_length is the maximum plaintext length supported for the
current hash type.

So if you're running John against traditional DES-based hashes, which
are limited to 8-character long passwords, then "<-" will be rejecting
anything shorter than 7.

The uses for this functionality are subtle.  I don't think you seriously
wanted to ask about it if you're just learning what rules are for.

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

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