Followup to: <Pine.LNX.4.21.0005260055450.13990-100000@server.serve.me.nl>
By author: Igmar Palsenberg <maillist@chello.nl>
In newsgroup: linux.dev.kernel
>
> > What if you simply tuned a cheap FM receiver to just static and fed
> > that into a soundcard. Then reading from /dev/dsp or something would
> > return pretty good random data, right ?
>
> Nope... Unless the receiver recieves a resonable amount of random
> interference, the data isn't considered random enough.
>
Thermal noise is probably your most easily available source of
randomness. The hard part is estimating the amount of entropy
derivable, unfortunately; electrical interference can cause the
entropy to be less than what you would expect. The /dev/random mixing
function takes care of removing the predictable stuff, but you still
need to get a value (conservative is fine) for the amount of entropy
actually available.
-hpa
-- <hpa@transmeta.com> at work, <hpa@zytor.com> in private! "Unix gives you enough rope to shoot yourself in the foot."- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Wed May 31 2000 - 21:00:15 EST