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Date: Sat, 31 Dec 2011 14:47:32 +0100
From: magnum <john.magnum@...hmail.com>
To: john-dev@...ts.openwall.com
Subject: Re: SSE/intrinsics for sapB/sapG [was: john-users]
On 12/31/2011 02:27 PM, magnum wrote:
> On 12/31/2011 04:30 AM, jfoug@....net wrote:
>>> Jim, Simon, how would I do a crypt of between 56 and 63 bytes? Is this
>>> not possible? Can we actually only do 0-55 *or* 64-119 bytes?
>>
>> To encrypt 56 bytes, do this:
>>
>> 1. set the 56 bytes, then set 0x80 as the 57th, and null out the rest.
>> Do the sha.
>> 2. create another buffer. NULL the entire buffer, but put 56<<3 into
>> the length location (last 8 bytes, BE format, I think).
>> 3. perform sha on this, using the results of step 1 as the init seed.
>
> This was almost correct. For the record, I had to put the 0x80 different:
Sorry, my bad. What you described is correct.
For 56-59 bytes we can do the above. For 60 bytes, I presume we put all
of them in the first buffer but the 0x80 in the second. For 61-63 bytes
we also need to put the last couple of bytes in the second buffer. For
64 bytes, we put everything in the first buffer but a 0x80 in the second.
I suppose the figures are sligthly different for MD4 and MD5, where the
length byte is placed at 14*4 instead of 15*4?
magnum
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