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The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:20:11 ADT
Ben Laurie (ben@algroup.co.uk)
Tue, 07 Jul 1998 22:36:45 +0100
Mike Rosing wrote:
> One of the main questions I have is what to look for as random data.
> The signal is periodic, every time there's a decay which passes thru the
> ion chamber there is a voltage peak. There is *always* a decay within
> 200 microseconds, when two decays occur almost simultaneously the voltage
> peak is very high. So I have both timing (zero cross overs) and raw
> voltage as possible sources of randomness.
>
> Any ideas on how to distill randomness from this data appreciated.
When you say "zero cross overs" I presume you mean something other than
zero (coz I'm kind of hoping that you can't make resistance negative).
More seriously, the conventional method is to measure them (that is the
timings, and, presumably, the voltage every so often) and add them to a
pool, which, once you've decided you've added enough bits of entropy to
it, you hash down to the number of bits you think you've really got. I
presume you already knew this, though, so I'm left wondering what you
are _really_ asking?
Cheers,
Ben.
-- Ben Laurie |Phone: +44 (181) 735 0686| Apache Group member Freelance Consultant |Fax: +44 (181) 735 0689|http://www.apache.org/ and Technical Director|Email: ben@algroup.co.uk | A.L. Digital Ltd, |Apache-SSL author http://www.apache-ssl.org/ London, England. |"Apache: TDG" http://www.ora.com/catalog/apache/WE'RE RECRUITING! http://www.aldigital.co.uk/recruit/
The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:20:11 ADT