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Message-ID: <4DAA2EDF.70204@bredband.net>
Date: Sun, 17 Apr 2011 02:05:51 +0200
From: magnum <rawsmooth@...dband.net>
To: john-dev@...ts.openwall.com
Subject: MS formats optimisations (was [john-users] New format: MS Kerberos!)
On 2011-04-10 16:55, magnum wrote:
> Performance is not very impressive, it's OpenSSL.
After having time to actually understand my copy-paste-hack better I
have realised the above is not true. It uses Solar's md4 and md5 and a
hmac_md5 originally from the Samba project, altered by JoMo-Kun so it
uses Solar's md5 routines. It does use OpenSSL's RC4 but that doesn't
even show up in profiling so it's not a problem.
In revision 12 of my patch I have optimised that hmac_md5 a little. It
was very inefficient, like first memsetting everything to zero, then
setting everything to something else. This also affected LMv2 and NETLMv2.
Anyway, in set_key() we produce an ordinary NT hash from the plaintext.
This also applies to NETNTLM, NETLMv2, NETNTLMv2. I wonder if this would
benefit from applying a modified copy of crypt_all_generic (or even
something arch specific) from NT_fmt.c? That one saves the last steps to
cmp_exact (or _one) so it can't be used as-is but I think I could puzzle
it together. But I'm not sure if it would perform that much better than
the current raw md4 when just producing one NT hash at a time as opposed
to a bunch of them?
NETLM and MSCHAPv2 has a similar "problem" in that their set_key() need
to produce an LM hash from the plaintext. These ones currently do use
OpenSSL. Maybe some of John's own DES code could be used there? I have
tried to digest it but there are optimisations and stuff that probably
makes it unusable as is? Like with the NT hashes, we really need a
proper hash, not a john-proprietary binary.
Any thoughts are welcome.
magnum
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