[149106] in cryptography@c2.net mail archive
Re: [Cryptography] cheap sources of entropy
daemon@ATHENA.MIT.EDU (Bill Frantz)
Sat Jan 18 14:04:08 2014
X-Original-To: cryptography@metzdowd.com
Date: Sat, 18 Jan 2014 10:07:07 -0800
From: Bill Frantz <frantz@pwpconsult.com>
To: cryptography@metzdowd.com
In-Reply-To: <52DA388D.8040708@iang.org>
Errors-To: cryptography-bounces+crypto.discuss=bloom-picayune.mit.edu@metzdowd.com
On 1/18/14 at 12:17 AM, iang@iang.org (ianG) wrote:
>Jon Callas (I think) a long time ago suggested pointing your cheapo USB
>camera at a photographer's grey card in low light. The theory is that
>the cells in a camera seek for information and if they don't see
>something that is worth reporting, it drives them a little tipsy. The
>claim is that this effect can drive them into some form of quantum
>uncertainty.
I think what is happening here is the effective ISO is being
pushed up by the low light so there is a lot of noise in the
amplifiers used to read out the sensor cells. What you are using
is thermal noise in the amplifiers. You get a lot of readings in
one photo, and it should be a good source.
>Open question: What do people think of the production of big important
>keys using the old compliance method of "must use a HSM" now ?
I have always looked at HSMs as black boxes built by people I
don't trust. If I built it I would feel different, but you
should be uncomfortable using my HSM. Getting mutually
suspicious people to trust the same HSM is an interesting
social/technical problem.
Cheers - Bill
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