Posted May 26, 2008 5:42 UTC (Mon) by ikm (subscriber, #493)
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Johnson noise and other crap like that. Usually it's not really totally uniformly random, but still quite unpredictable :)
Appropriate sources of entropy
Posted May 30, 2008 22:16 UTC (Fri) by ejr (subscriber, #51652)
[Link]
Search for "randomness extractor" for information on turning an unknown
random distribution into a known one. It's quite difficult, but often
possible. Cool combinatorics at work, and also closely related to error
correcting codes and hashing. (They're all related by the concept of
distance between and distinguishability of the sampled points.)