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Date: Tue, 28 May 2013 11:58:07 -0400
From: Rafael Veras <rafaveguim@...il.com>
To: john-users@...ts.openwall.com
Subject: Re: Help with uppercase rule
Wow, that's really tricky!
Thanks a lot, it makes sense now.
On Tue, May 28, 2013 at 11:31 AM, Matt Weir <cweir@...edu> wrote:
> I know you only had questions about a couple parts of the rule, but to help
> everyone else out I'm just going to break down the entire the rule part by
> part, (explanations separated by a ':')
>
> -c : Reject rule if the hashtype is case insensitive, (for example LanMAN.
> No sense having an uppercase rule if everything is going to be
> automatically uppercased anyway)
> >2 : Only try words greater than two characters long
> !?X :Reject the rule if it contains a non-alpha numeric character. Aka
> not [a-zA-Z0-9].
> This is a tricky rule as ! is for reject, and ?x is for alpha numeric
> character, so capitalizing the 'X', aka ?X matches everything not alpha
> numeric.
> u: converts the word to uppercase
> Q: query memory to see if the rule has changed the word. Reject it if
> nothing has changed. Aka no sense making a guess if the word is '123456',
> or 'ABCD' since you will have already tried them with the ':' default rule
> M: Memorize the newly mangled word. This is where things get really
> complicated. Long story short, we want to reject all guesses that would be
> created by a simple capitalize rule since that would create duplicate
> guesses when we called the capitalize rule. So the rest of the checks are
> to remove those duplicates. Aka reject the word 'a12345' when it is
> uppercased to 'A12345'.
> c: capitalize the mangled guess. So 'PASSWORD' is changed to 'Password'.
> Note, it will only change if any letter but the first letter is
> capitalized.
> Q: Reject the guess unless it has changed. Aka only accept it if there were
> letters to capitalize that were not the first character
> u: Finally uppercase the word to reverse the capitalization we did earlier
> to detect duplicate guesses
>
> Matt
>
>
> On Tue, May 28, 2013 at 10:57 AM, Rafael Veras <rafaveguim@...il.com>
> wrote:
>
> > After reading the documentation, I'm still left with some questions about
> > the following rule:
> >
> > # Uppercase pure alphanumeric words
> > -c >2 !?X u Q M c Q u
> >
> > 1. What does !?X mean?
> >
> > 2. Why c (capitalize) is called after uppercase (u)? I thought capitalize
> > wouldn't have any effect after uppercase.
> >
> > 3. Why is uppercase called once again in the end?
> >
> > I guess I am missing something about the Q and M commands that occur in
> > between.
> >
> > Thanks,
> >
> >
> > --
> >
> > *Rafael Veras*
> >
> >
> >
>
--
*Rafael Veras*
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