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Message-ID: <20120215155320.GA2485@openwall.com>
Date: Wed, 15 Feb 2012 19:53:20 +0400
From: Solar Designer <solar@...nwall.com>
To: john-users@...ts.openwall.com
Subject: Re: sha1 + hex salt
On Wed, Feb 15, 2012 at 09:28:34AM -0600, jfoug wrote:
> I really wonder if the description of this crypt is wrong. I bet this is
> simply a fixed 16 byte null buffer, that has the password overwrite the
> first part of this buffer, and then is crypted with SHA1. This is similar
> to how cisco pix works (but pix used md5). I.e., we are seeing a fixed
> sized null padded password buffer.
>
> Thus, it may be better for this crypt, to do this type pseudo code:
>
> clean_buffer (whole buffer is NULL).
> append_key
> set_length_16 (I do not think this function exists in dynamic right now)
> sha1_crypt
Actually, this appears to work:
[List.Generic:dynamic_1998]
Expression=sha1($p NUL-padded to length 16)
Flag=MGF_SHA1_40_BYTE_FINISH
Func=DynamicFunc__clean_input
Func=DynamicFunc__append_keys
Func=DynamicFunc__set_input_len_16
Func=DynamicFunc__SHA1_crypt_input1_to_output1_FINAL
Test=$dynamic_1998$20c59472b34ec4b9678b7149d519a2338bc31ba9:92086390
$ ./john -te=1 -fo=dynamic_1998
Benchmarking: dynamic_1998 sha1($p NUL-padded to length 16) [SSE2i 10x4x3]... DONE
Raw: 5561K c/s real, 5561K c/s virtual
$ ./john --format=dynamic_1998 -i=digits pw
Loaded 1 password hash (dynamic_1998 sha1($p NUL-padded to length 16) [SSE2i 10x4x3])
92086390 (?)
guesses: 1 time: 0:00:00:10 DONE (Wed Feb 15 19:48:39 2012) c/s: 5136K trying: 92080055 - 92086591
I think 10 seconds is an improvement over 15 minutes. ;-)
I also tested a linux-x86-mmx build on a 1 GHz P3 - works as well (but
slower, indeed - takes a little over 1 minute to crack the same password).
Alexander
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