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Message-ID: <20111215150640.GB5278@openwall.com>
Date: Thu, 15 Dec 2011 19:06:40 +0400
From: Solar Designer <solar@...nwall.com>
To: john-dev@...ts.openwall.com
Subject: Re: Bit slice implementation of DES based hashes
Piyush -
On Thu, Dec 15, 2011 at 05:51:14PM +0530, piyush mittal wrote:
> In File DES_bs_b.c Three methods are given i.e
> 1,DES_bs_crypt_LM()
> 2.DES_bs_crypt_25
> 3.DES_bs_crypt()
>
>
>
> The first two is specific to Lm and Traditional DES respectively.First one
> calls the S-boxes in ECB mode and for second one I don't
> know.Third one i hope don't use any mode.However in oracle_fmt_plug.c
> conversion we need CBC mode so how to call S Boxes in this case?
You need to introduce a fourth function. I suggest that you take
DES_bs_crypt_LM(), copy it to a new function, and remove the
initialization of B from there (let the caller specify the initial B).
This way, you get a function implementing one DES block encryption
(for DES_BS_DEPTH different blocks and/or keys in parallel). As to
block cipher modes, you'll implement those externally to that function
(at least initially).
Another question I expected from you was how to set arbitrary DES keys
when the current DES_bs_set_key*() functions accept ASCII strings only.
I'll answer this one without waiting for you to ask it. ;-) I suggest
that you simply use DES_bs_set_key() for now, but set bit 8 in every
char (OR it with 0x80) to ensure that all 8 chars (with 7 significant
bits per char) are processed. We may introduce a more efficient binary
key setup function later.
Thanks,
Alexander
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