🚀 go-pugleaf

In article 700 Adam J. Richter writes:
>	Here's a note for you cryptography wizards out there.
>Assuming that there isn't some kind of bug in the program I used to
>deduce this, I think I've found an interesting property of the
>S-boxes.  I have no idea how this might be useful and I have no idea
>whether this property is a strength of DES, a weakness of DES, an
>irrelevant artifact of DES, or a bug in my program.  (Source code is
>at the end.)

>	Consider the following question.  For s-box S, input bit I,
>and output bit O, how many input bit combinations that have input bit
>I set result in output bit O being set, for s-box S?  (Or, "how many
>input-ouptput pairs for s-box S have both input bit I and output bit O
>set?")

He then tells us that this number is very regular indeed- exactly
equal to the average (16) for the last two bits of any S-box.

We have here in Amsterdam a real group of cryptographers, and spent some
time at the problem. We did not find a reason why this would implicate
the cryptographic qualities of DES (although it is likely) but we must
admit that this is at least a remarkable coincedence.

We did not find a bug in Adam's program.

I strongly suggest that anyone who likes to struggle a little with bits
plays with this, may someone will find something.

PS about the simplification of the logical equations of DES: humbug.
Those equations never will give a result that is more efficient that
key search.

Jurjen.