On Thu, 29 Jul 2004, Andy Polyakov wrote:

> >>>>Note that 3rd argument to padlock_xstore is no longer void ** and second
> >>>>argument to more diverse, 1 and 3.
> >>>
> >>>I read somewhere that with edx=3 the RNG gives the "best" random
> >>>numbers.
> >>
> >>Well, it's most "wasty" that's for sure:-) I mean it seem to compress 8
> >>bytes to 8 bits.
> >
> > Wasty ... maybe. But you usually need not too much bytes with a good
> > entropy instead of a fast flow of numbers with poor entropy. How about
> > using the "slow" variant as RNG and the fast one as PRNG? There are
> > different entries for both in the RAND_METHOD structure.
>
> I'm actually leaning toward opinion to #if 0 RNG at initial commit to
> CVS. The evaluation report (at via site)  maintains that edx=3 should be
> used for non-secure applications [such as monte-carlo simulations]. For
> cryptographic applications they recommend to pool values collected with
> edx=0 and whiten them with secure hash. For all applications they
> explicitly discourage rep prefix and recommend to thoroughly check
> returned eax after each xstore instruction. Another concern is that
> registering RAND_METHOD has an "usurping" effect on RAND_bytes and
> proposed code provides no error control whatsoever. In other words in my
> opinion further consideration is required... Shall we settle for this
> for now?

Well ... yes. RNG is not that critical (although it's a loss to not use it
when it is there). But go ahead with the CVS commit without RNG.

> I also wonder if you have any hints on what one should look for if one
> wants to build system based on this CPU?  Particular CPU models
> (steppings to avoid), mothercards (would any 370 card do?), cooling
> required... Stuff like that... A.

ACE is available in VIA Nehemiah stepping 8 and higher. I have one such
CPU on a C3M266 board (socket 370) with a standard fan taken from an older
Athlon. I don't know if those cool mini-ITX boards with a passive cooler
are already available with this new Nehemiah. You should ask VIA or their
resellers for availability and requirements. All that I can recommend
is the correct stepping ;-)

Michal Ludvig
-- 
* A mouse is a device used to point at the xterm you want to type in.
* Personal homepage - http://www.logix.cz/michal
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