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The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:19:06 ADT
Adam Shostack (adam@homeport.org)
Thu, 25 Jun 1998 17:10:22 -0400 (EDT)
Max volume usually doesn't peg a system. What happens as you get
above the analog's equipments to handle it is distortion, which gets
sent to the D/A stuff.
Also, white noise, such as from a machine floor or jet engine, ends up
being very 'choppy' in binary. Its not a continuous tone that
produces the same levels. If you use a whitening technique such as
counting parity of the number of bits between transitions, you
probably will get decent randomness. The worse situation is not
having the mike functional, so the DA converter gets no input. (Cat
/dev/audio on a sun with no mike.)
Adam
Kriston J. Rehberg wrote:
| One thing I've always wondered about are these listening random number
| generators (I understand they are on certain kinds of FORTEZZA cards)
| that use sound for entropy. What if the ambient sound is at such a
| volume, such as on a machine floor, that the listening device's input is
| so distorted and its values are always pegged at some "maximum" level,
| that it provides no entropy at all?
|
| Kris
|
| Eric Murray wrote:
| >
| > Perry E. Metzger writes:
| > >
| > >
| > > No general page (it would be GREAT if someone had a general page on
| > > hardware RNG equipment), but the reference http://lavarand.sgi.com/
| > > will at least amuse you.
| >
| > http://nz.com/webnz/robert/recent/lottery.html is a
| > decent hardware RNG reference.
| >
| > A question: what would it be worth to have a cryptographic-quality
| > hardware RNG available on consumer PC equipment? I.e. how many
| > retail dollars do you think that the typical consumer would spend
| > for it? This question is more a business question than a technical
| > one (excepting the fact that its people paying money that drives
| > most techologies) so perhaps replies should be sent to me instead of the list.
| >
| > --
| > Eric Murray Chief Security Scientist N*Able Technologies www.nabletech.com
| > (email: ericm at lne.com or nabletech.com) PGP keyid:E03F65E5
|
| --
| Kriston J. Rehberg
| http://kriston.net/
| AOL: Kriston endeavor to persevere
|
-- "It is seldom that liberty of any kind is lost all at once." -Hume
The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:19:06 ADT