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Date:      Mon, 16 Oct 1995 07:57:41 +0200
From:      Mark Murray <mark@grondar.za>
To:        Dave Hayes <dave@elxr.jpl.nasa.gov>
Cc:        hackers@freebsd.org
Subject:   Re: Creating a /dev/random 
Message-ID:  <199510160557.HAA25208@grumble.grondar.za>

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> Mark Murray <mark@grondar.za> writes:
> >I am building devices, /dev/random and /dev/urandom that when read give
> >random noise generated in and by the kernel. 
> 
> How is this noise generated? Is it really random, by statistical
> tests?

It is very random, and I believe it will survive the most rigorous tests.
The code maintains a pool of entropy, which is added to by system events
such as interrupts, timer events eystrokes etc. As entropy is removed,
the entropy count is reduced, and as events come in, this is increased.

If you like, I can forward the code...

> Is there any chance of having an option to take random bits from an
> existing sound card if there is one there?

Sure. That is a _great_ source of noise if the card is properly set up.

M

--
Mark Murray
46 Harvey Rd, Claremont, Cape Town 7700, South Africa
+27 21 61-3768 GMT+0200
Finger mark@grumble.grondar.za for PGP key



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