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Date: Fri, 8 Feb 2013 16:50:45 -0500
From: Lex Par <ziptied@...il.com>
To: john-users@...ts.openwall.com
Subject: Re: Cracking SHA1 with some knowledge of password

This might be a silly question, but why is there a 55 byte max?



On Fri, Feb 8, 2013 at 4:44 PM, jfoug <jfoug@....net> wrote:

> This should work.  Be SURE to use the latest JtR  (but I did test with
> 1.7.9-jumbo5 Win32 build from JtR download page, and it worked there, but
> was slower).
>
> [List.Generic:dynamic_1050]
> Expression=xxxSHA1($p)yyy
> Flag=MGF_SHA1_40_BYTE_FINISH
> MaxInputLen=19
> Func=DynamicFunc__clean_input
> Func=DynamicFunc__append_input1_from_CONST1
> Func=DynamicFunc__append_keys
> Func=DynamicFunc__append_input1_from_CONST2
> Func=DynamicFunc__SHA1_crypt_input1_to_output1_FINAL
> Const1=something here\x20
> Const2=\x20and other stuff here
> Test=$dynamic_1050$6f4ba502c5885a980229162861134e4ed09c9351:openwall
>
> NOTE, the max input length set to 19 bytes. This is due to the 'extra' data
> being 36 bytes long, and we need to keep this inside 55 bytes max.  I also
> changed the const values, and recomputed the hash.
>
> $ echo -n "something here openwall and other stuff here" | sha1sum
> 6f4ba502c5885a980229162861134e4ed09c9351 *-
>
>
> From: Lex Par [mailto:ziptied@...il.com]
> >
> >thanks Jim! I'd liek to use your approach.  When I add what you specified
> in my conf file and run:
> >
> >./john --format dynamic_1050 --test
> >
> >I get:
> >Invalid format dynamic_1050 xxxSHA1($p)yyy;  The first command must be a
> clean input 1 or input 2 OR a special key 2 input loader function Unknown
> ciphertext format name requested
> >
> >xxx is really "something here "
> >and yyy is really " and other stuff here"
> >
> >both with spaces included...
>
>
>

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