Date: Wed, 23 Aug 1995 19:09:35 +0100 From: Andrew.Spring@ping.be (Andrew Spring)
I've been looking at using the Mac's Sound Input Manager for hardware RNG.
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I suspect there's much less entropy in that signal than even this estimate,
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Does anybody have any experience/advice in this area?
I would try injecting noise and seeing how well you can control the output signal. I would also do a Fourier transform of the output and look for cyclic behavior -- then see how the frequency spectrum can be modified by turning machinery on and off, turning radios on and off, .... You can also try various compression algorithms to see how much entropy they claim to see. When that's done, you can then use some of my ranno conditioning code, free on the net (although written for UNIX, for now): http://www.clark.net/pub/cme/html/ranno.html I especially like running a pseudo-random stream through ranM and then a hash, to obliterate any patterns which might sneak past your analysis. - Carl +--------------------------------------------------------------------------+ |Carl M. Ellison cme@acm.org http://www.clark.net/pub/cme/home.html | |PGP: E0414C79B5AF36750217BC1A57386478 & 61E2DE7FCB9D7984E9C8048BA63221A2 | | ``Officer, officer, arrest that man! He's whistling a dirty song.'' | +----------------------------------------------------------- Jean Ellison -+