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Date: Thu, 31 Jan 2013 09:03:00 +0400
From: Solar Designer <solar@...nwall.com>
To: john-dev@...ts.openwall.com
Subject: Re: NetNTLMv1

On Thu, Jan 31, 2013 at 07:59:52AM +0400, Solar Designer wrote:
> Oh, here's an idea: what if we apply the DES encryption (or decryption)
> to the last of the 3 blocks, not the first?  Doesn't the last block
> contain only like a couple of non-zero bytes?  (I don't recall.)  If so,
> we could replace this instance of DES with a lookup table, computed just
> once (e.g. at program startup, to avoid increasing program size).

I took a look.  It's the last portion of the key, not block, that
contains only 2 bytes.  The table can't be precomputed just once because
it depends on the challenge, but it can be precomputed in salt() (higher
memory usage) or set_salt() (lower memory usage, but also lower speed).

Alexander

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