From: Matt Blaze <mab@crypto.com>
Date: Sat, 12 Aug 95 10:30:21 PDT
Subject: Re: Still more "S-1" foolishness
In-Reply-To: <199508112206.SAA27354@crypto.com>
Message-ID: <199508121738.NAA05367@crypto.com>
MIME-Version: 1.0
Content-Type: text/plain



I wrote:
>Here's a table of where the expanded key schedule bits come from
>(I think - this could be wrong, I had to tweek some of the output
>by hand).  Note that some key bytes are used much more often, and
>in more positions, than others, but every key byte does at least
>end up being used as input to each F eventually (but not always to
>each "target" byte).
>
>Sorry for the opaque notation; this reads best when used in conjunction
>with Colin's cool graph that he posted to sci.crypt last night.
>

Whoops - there was a bug in my understanding of what was going on
that conspired with a bug in my table generation program to make everything
wrong.  Here's the correct table, for those interested.  Sorry for the noise.

-matt


 R |    | G0   G1  F+0  F+1  F+2  F+3   (this key byte is input to this fn)
 O bytes| R+4  R+5 R+2  R+3  R+0  R+1   (key byte is mixed with this block byte)
 U |enc-| all  all R+6L R+6H R+7L R+7H  (output affects this byte)
 N |rypt| 0    1    2    3    4    5    (key schedule byte #)
 D |ed  |LLHH LLHH LLHH LLHH LLHH LLHH  (posn of orig key byte in sched byte)
======================================
 0  76   5831 9425 5362 4738 8492 5038 
 1  10   1497 5081 1928 0394 4058 1694 
 2  32   7053 1647 7584 6950 0614 7250 
 3  54   3619 7203 3140 2516 6270 3816 
 4  76   9275 3869 9706 8172 2836 9472 
 5  10   5831 9425 5362 4738 8492 5038 
 6  32   1497 5081 1928 0394 4058 1694 
 7  54   7053 1647 7584 6950 0614 7250 
 8  76   3619 7203 3140 2516 6270 3816 
 9  10   9275 3869 9706 8172 2836 9472 
10  32   5831 9425 5362 4738 8492 5038 	(number indicates position in schedule
11  54   1497 5081 1928 0394 4058 1694   of original key bytes; an entry
12  76   7053 1647 7584 6950 0614 7250   "5678" means key bytes 5 and 6 are
13  10   3619 7203 3140 2516 6270 3816   in the low order position of this
14  32   9275 3869 9706 8172 2836 9472   schedule entry and bytes 7 and 8
15  54   5831 9425 5362 4738 8492 5038   are in the high order position.  Bytes
16  76   1497 5081 1928 0394 4058 1694 	 are first run through an F functuon
17  10   7053 1647 7584 6950 0614 7250   and XORd with each other to create
18  32   3619 7203 3140 2516 6270 3816   the schedule nibble.)
19  54   9275 3869 9706 8172 2836 9472 
20  76   5831 9425 5362 4738 8492 5038 
21  10   1497 5081 1928 0394 4058 1694 
22  32   7053 1647 7584 6950 0614 7250 
23  54   3619 7203 3140 2516 6270 3816 
24  76   9275 3869 9706 8172 2836 9472 
25  10   5831 9425 5362 4738 8492 5038 
26  32   1497 5081 1928 0394 4058 1694 
27  54   7053 1647 7584 6950 0614 7250 
28  76   3619 7203 3140 2516 6270 3816 
29  10   9275 3869 9706 8172 2836 9472 
30  32   5831 9425 5362 4738 8492 5038 
31  54   1497 5081 1928 0394 4058 1694