From: "Josh M. Osborne" <stripes@va.pubnix.com>
Date: Wed, 9 Aug 95 17:59:48 PDT
To: Hal <hfinney@shell.portal.com>
Subject: Re: "S1" encryption system (was: this looked like it might be interesting)
In-Reply-To: <199508092259.PAA10092@jobe.shell.portal.com>
Message-ID: <UAA08495.199508100059@garotte.va.pubnix.com>
MIME-Version: 1.0
Content-Type: text/plain


In message <199508092259.PAA10092@jobe.shell.portal.com>, Hal writes:
>I suppose the unstated implication is that this might be Skipjack.

I don't suppose anyone has access to Skipjack to verify or
refute this claim?

[...much intresting analisys deleted...]
>                                           In addition to the points
>mentioned it is curious that the G arrays are initialized with a list of
>256 values rather than taking advantage of the apparent regularities
>noted.

It is fairly simple to cut & paste 10 values ~25 times, it is harder
to write and verify code to initilize the array.

More intresting is that Gx[i % 10] is faster then a stright index
on many systems (anything you could expect cache line conflicts or
cache capacity overfills on, and supports a modulis signifigantly
faster then the first few parts of the memory hierachy).

Also note that the code may have been written from a dissasembled
binary rather then a hardware spec.

[...]
>Hal Finney
>hfinney@shell.portal.com
>