Date: Wed, 30 Jan 2013 14:02:21 -0600 From: "jfoug" <jfoug@....net> To: <john-dev@...ts.openwall.com> Subject: RE: Speeding up WPAPSK, by leveraging salt shortcomings From: magnum [mailto:john.magnum@...hmail.com] > >Here's a beautyfully simple thought: If we could force John to serve the salts (the current code's salt structs) in essid order, so any same-essid salts would always be *consecutive*, we'd do fine with this one-line change to crypt_all: Been thinking a little on this one. This is the first time (that I am aware of), where order of salts makes a difference. so up to this point, I think there has been no thought put into it. How about this: 1. make an array of pointers into the salt data (it may, or likely is done this way already). 2. the salt loading currently does load_salts, strike_out_pot, build_final_salt. It is not exactly like this, but I think this explanation is close enough so that solar (or magnum) would know the exact mechanics. 3. I propose we add an optional step to this loading. It will be 'similar' to a qsort. This would require changing the format. There will be an 'optional' (almost always set to default) method added. This method will be like the function used by qsort, and hell, we even COULD use qsort to actually do it. qsort is: qsort(void *_Base, size_t _NumElements, size_t _sizeOfElement, int(__cdecl *_ptFuncCompare(const void *, const void*)) So, I propose we add a new function to format methods. This function is: int salt_sort(const void*, const void*); Then if this function is not set to default_salt_sort, we call qsort on our data, using that function as the compare function. That function would have to be either given a pointer to the salt itself, or would have to be smart enough to convert the pointers given into the proper structure, so that the salt could be located. However, is 'should' be the format, that is in charge of ordering salts. The format designer will need to know that it DOES matter, and know exactly how to order things. That way common CRTL functions like qsort would properly order this data, even if we had several formats needing this work. JtR would not need to know anything to do this, the format would own any logic on what is needed. On a side thought, would this same method be beneficial for sorting input words?? Jim.
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