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Message-ID: <ce99cf08d6d23534bf91c8030062c371@smtp.hushmail.com>
Date: Sun, 01 Jul 2012 14:07:18 +0200
From: magnum <john.magnum@...hmail.com>
To: john-dev@...ts.openwall.com
Subject: Re: raw-sha1-ng reduced binary size

On 2012-07-01 13:51, magnum wrote:
> On 2012-07-01 13:20, Tavis Ormandy wrote:
>> magnum <john.magnum@...hmail.com> wrote:
>>> BTW you still advertise a BINARY_SIZE of 20 octets although you would do
>>> perfectly fine with 4. The difference is very far from neglectable if you
>>> load a couple of million hashes. I *really* think this should be your #1
>>> goal and it's a walk in the park. Take a look at a late rawSHA1_fmt_plug.c
>>> and look for BINARY_SIZE vs DIGEST_SIZE.
>>>
>>> magnum
>>
>> I understand, I'm just not sure it's worth the performance penalty (because
>> I can't treat it like a dqword in cmp_all). I can think of a faster format
>> if I store it redundantly, like:
>>
>> SHA1  =00112233 44556677 aabbccdd eeff3344 eeaa1122
>> BINARY=EEAA1122 EEAA1122 EEAA1122 EEAA1122
>>
>> Then I only have to shuffle it once, instead of once per cmp_all. That's a
>> saving of 4 bytes per hash, and I can still use it like a dqword, is that
>> ok?
> 
> Sure, I did not realize you would end up with a slower cmp_all. There
> should be some way around that.
> 
>> I made both changes, so you can choose. I sent you a pull req for the 16byte
>> one, but the 4byte one is here if you prefer:
>>
>> https://github.com/taviso/magnum-jumbo/commit/88ea3e884b7a0bfd5f2452d864c5cc6244fc3f34

You mean ac3bb1951d6f44cad71b9b2d39a095ff140bb2de, right?

magnum

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