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Message-ID: <20100817081856.GA654@openwall.com> Date: Tue, 17 Aug 2010 12:18:56 +0400 From: Solar Designer <solar@...nwall.com> To: john-users@...ts.openwall.com Subject: Re: Consonant Vowel Patterns On Thu, Aug 12, 2010 at 09:17:40AM -0400, Brad Tilley wrote: > I wanted to ask if others had experimented with consonant vowel patterns > in password cracking? I briefly played with something like this in 1995 or so, and the code stayed around for a few years longer (before being dropped). Specifically, early revisions of what became JtR's incremental mode had an optional builtin filter (called "wordlike") that would skip candidate passwords that contain too many consecutive vowels or consonants. It insisted on having no more than 2 consecutive consonants and no consecutive vowels (OK, this wouldn't work for Dutch), although these numbers were easy to edit in the code: bzero(vowels, sizeof(vowels)); vowels['a']++; vowels['e']++; vowels['i']++; vowels['o']++; vowels['u']++; vowels['A']++; vowels['E']++; vowels['I']++; vowels['O']++; vowels['U']++; [...] if (wordlike) { *(long *) & classcount = 0; for (wpos = 0; wpos < usecount; wpos++) { classcount[classindex = vowels[word[wpos]]]++; classcount[classindex ^ 1] = 0; if (classcount[0] > 2 || classcount[1] > 1) break; } } This was of some help with pre-JtR and early JtR revisions of the code. At the time, the sorted character lists were not per-position (there was just one list initially, then three lists for beginning/middle/end). Then per-position lists were introduced. Then .chr files with per-preceding-two-characters lists were introduced (effectively storing info on trigraphs). By this point, the "wordlike" filter was fully obsoleted, so it was eventually not included into a new revision of the code (written in 1997-1998, which became JtR 1.5+). The above code snippet came from JtR 1.4 released in 1997, although "wordlike" was already obsolete by then (JtR 1.4 already had support for .chr files). It's just that I did not drop the code separately from the rewrite for 1.5+. Alexander
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