Date: Tue, 18 Aug 2015 10:23:19 +0200 From: magnum <john.magnum@...hmail.com> To: john-dev@...ts.openwall.com Subject: Re: Formats using non-SIMD SHA2 implementations On 2015-08-18 09:05, Lei Zhang wrote: > On Aug 18, 2015, at 12:41 PM, jfoug@....net wrote: >> >> On Mon, 17 Aug 2015 22:51:26 -0500, Lei Zhang <zhanglei.april@...il.com> wrote: >> >>> Or perhaps I didn't understand your point correctly ? >> >> It sounds like you understand it well enough. Now, can I ask, what variables >> make up the growth of the lanes ? Is is solely based upon password length? >> Keep in mind, that if it is a combination of password and salt, then all >> you have to care about is password. Within any run, you ONLY deal with >> one salt at a time. > > It's a combination of password and salt. The entire length of data to be hashed is (len(password) + 8)*rounds, where 'rounds' is solely based on salt. That's assuming 'password' is already in UTF-16, right? So for ASCII the number of raw SHA256 calls should be (len(password) * 2 + 8) * rounds / 64. Plus one for the final. So for length 0 it's 65537 calls to SHA256, for length 1 it's 81921, and so on. >> But if this variable length is solely based upon >> length of password, then simply have 'enough' passwords, and sort them, >> so that you work with only passwords of a given length at the same time. > > How do I do this exactly? If it's lengthy to explain I can chew some sample code myself :) I believe cryptsha256_fmt_plug.c lines 619-626 is the heart of it. In that format, groups of lengths use the same buffer size. I think for 7z and rar3, you won't need the 'lens' static array, all lengths will use a different number of limbs. magnum
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