[689] in cryptography@c2.net mail archive
Re: Random numbers from the '60's...
daemon@ATHENA.MIT.EDU (Phil Karn)
Mon May 5 19:31:59 1997
Date: Mon, 5 May 1997 16:23:42 -0700 (PDT)
From: Phil Karn <karn@qualcomm.com>
To: brettc@tritro.com.au
CC: stewarts@ix.netcom.com, cryptography@c2.net
In-reply-to:
<c=AU%a=_%p=Tritronics_.Aust%l=TRI_NT5-970502011533Z-1074@net.tritro.com.au>
(message from Brett Carswell on Fri, 2 May 1997 11:15:33 +1000)
>I'm pretty sure that what Phil is referring to is using the noise
>generated by the preamp without a microphone connected. As far as I'm
>aware this is similar to shot noise in resistors which generates pretty
>nice random bit sequences.
Right, though having a microphone attached certainly won't hurt. My
point was simply that a microphone isn't *essential*, as it's been my
experience that the microphone preamp on a typical soundblaster card
is quite noisy. Just crank the gain all the way up and hash the resulting
noise. If you do have a microphone connected, so much the better. Just
make sure the speaker is muted to avoid some annoying screeches.
By the way, the Linux /dev/random driver already accepts external
seeding information. So seeding it from the microphone can be as easy
as
$ cat /dev/audio > /dev/random
(wait a few seconds, then hit ^C)
--Phil
