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Message-ID: <20111220160433.GB10482@openwall.com>
Date: Tue, 20 Dec 2011 20:04:33 +0400
From: Solar Designer <solar@...nwall.com>
To: john-dev@...ts.openwall.com
Subject: Re: Bit slice implementation of DES based hashes
On Tue, Dec 20, 2011 at 05:56:15PM +0530, piyush mittal wrote:
> >
> > Can you please describe what bitslicing is, in your own words?
>
> In Bitslicing ,all combination of bits operates simultaneously and
> parallelly i.e each bit will behave as a different processor.
Each bit of what?
> The same
> concept we are using here in DES.Like in 64 bit machine 64 plain text's
> encryption can be done simultaneously and parrallely.
OK.
> However here we have
> used non standard implementation of DES i.e structure of DES is broken down
> into AND,OR NOR.. gates to further increase the speed.
"To further increase the speed"? Would there be any speed increase at
all (compared to a non-bitslice implementation) without this? And what
alternative(s) did we have?
> > What portion(s) of the DES block(s) does each element of B[] hold?
> >
> > What portion(s) of the DES key(s) does each element of K[] hold?
>
> 64 elements of block is holded by each element of B[]
> 56 elements of block is holded by each element of K[]
These two are not valid answers to my questions. Here are some
ridiculous questions in line with your answers above:
What is an "element" of a block?
Are you implying that one element of B[] has a different size than one
element of K[] (64 "elements" in it vs. 56 "elements")? Is this
discrepancy also seen in the data types used in the program? If not,
what does that mean?
I am sorry for asking those questions like that, but I think that you're
missing some of the basics and I am trying to get you to realize what
exactly you're missing and learn that.
> Now I am starting NETLM_fmt.c and Oracle code I will also give you after it.
> Now I will not inquire further questions to you.
OK, that's your choice.
Alexander
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