New entropy source proposal.

Pawel Jakub Dawidek pjd at
Mon Mar 7 13:17:34 GMT 2005

On Mon, Mar 07, 2005 at 02:07:11PM +0100, Poul-Henning Kamp wrote:
+> In message <20050307130330.GX9291 at>, Pawel Jakub Dawidek wr
+> ites:
+> >I've been playing a bit with "use sound card as an entropy source" idea.
+> >This simple program does what I wanted:
+> Can you give a quick summary:
+> 	What sample setting do you use ?
+> 	What gain setting do you use ?
+> 	Have you run experiements where you have attached various
+> 	signal sources to the input ?  Music ?  Pure sine tone ?

I didn't make any sound card configuration nor connected sound source.
It was just pure noice (no microphone attached).

/dev/dspW uses 16-bit little endian encoding and I only use less
significant 8 bits. As I read "Open Sound System" guide, on sound
device open it works in 8kHz mono mode. So that was my testing

I'm not an expert in this area, of course, just playing around and giving
a start for future research, I hope.

Pawel Jakub Dawidek             
pjd at                 
FreeBSD committer                         Am I Evil? Yes, I Am!
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