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The following archive was created by hippie-mail 7.98617-22 on Thu May 27 1999 - 23:44:23
Bill Stewart (bill.stewart@pobox.com)
Mon, 26 Apr 1999 23:34:31 -0700
At 10:07 PM 4/26/99 +0100, Mj Dascombe wrote:
>Has it ever been suggested that seperate hardware be used to generate
>the random bits required for key generation.
Yes. Go look for "hotbits" somewhere under fourmilab.ch ...
There's also been a lot of discussion on various lists,
some of which may be known to popular search engines,
about hardware random number generation using thermal noise
in diodes and other relatively cheap non-radioactive approaches.
>I created such a device using a FLIPFLOP
>random bit circuit and a clock, attached to pin 2 of an RS232, wich
>provided a terminal program with random characters. Would these characters
>not be random beyond question?
If the input is really "random beyond question", then you can calculate
how random the output will be. (If you've learned the maths to do that...)
But that's begging the question - how random is the input? Can you prove
it?
What kinds of correlations are there? How would you test for them?
Is there some reason to expect the timing of your flipflop to be
independent of the timing of your clock? What if they're correlated?
Is there any signal leakage from the output back to the input?
What effects would that have on the randomness of the system?
How would you measure it? Could your flipflop's state be
derived from the same clock that your system clock is?
How much skew is there? How many good random bits are you getting per second?
If you're studying science, you can always ask questions,
and if you're studying engineering, you can always measure stuff.
If you're a mathematician, you can occasionally get beyond questions
by proving things using known techniques and good starting points,
but that's mainly useful if your starting points are good,
which gets you back to the engineering and science questions.
Thanks!
Bill
Bill Stewart, bill.stewart@pobox.com
PGP Fingerprint D454 E202 CBC8 40BF 3C85 B884 0ABE 4639
The following archive was created by hippie-mail 7.98617-22 on Thu May 27 1999 - 23:44:23