Messages in this thread | | | From | John Bradford <> | Subject | Re: Want a random entropy source? | Date | Sat, 28 Dec 2002 20:39:16 +0000 (GMT) |
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> > I was astonished to see that the resulting signal is a white-noise > > pattern with a slight emphasis at the high end (when sampled at 44 > > kilosamples per second). In short, it looks like diode noise with a > > 4 kilohertz square wave thrown in. > > "That suggests to me that this would make a fair source of random samples, > > especially after you slot out the interfering signal. > JB> How can you guarantee that you are sampling noise, though, what if a > JB> sound card was picking up 50 Hz mains hum, for example, that would > JB> de-randomise the data quite a bit. > > Well, the 50hz from the mains isn't a perfect 50hz; it has random (yes) > fluctuations.
Yes, that's true.
More generally, though, is there any point in this going in to the mainline kernel, if:
* Most users don't need faster entropy generation than we've got
and
* The entropy gathered from the soundcard is statistically inferior to that gathered from the current sources of entropy.
I don't see how it's possible to guarantee that the data below a certain dB level from the soundcard is noise.
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