Re: [Khufu] Pre-Computing the S-Boxes and obtaining aux. keys

From: Matt (matt_crypto_at_yahoo.co.uk)
Date: 10/31/04 

Date: 31 Oct 2004 13:53:26 -0800

Zeljko Vrba <ime.prezime@oss.unist.hr> wrote:
>
> In article <MPG.1beefb60f460327c989981@localhost>, Nikola Skoric wrote:
> >
> > Now, do you know where could I start asking for patent document?
<snip>
> http://tirnanog.ls.fi.upm.es/Servicios/Software/ap_crypt/indice.html
>
> as its first link.. there you can download khufu implementation together
> with the S-box generator..

The problem with this implementation is that it doesn't appear to use
the "canonical bootstrapping" S-box that is (somehow) derived from the
RAND random number list; it seems to just use a library PRNG instead:

/* make the initial sbox... (this is just a quick hack for now) */
srandom(seed);
for (i = 0; i < 256; ++i)
   InitialSBox[i] = random();

The Khufu and Khafre patent number is #5,003,597 and you can look it
up online here:

http://patft.uspto.gov/netahtml/srchnum.htm

Matt