hardware RNG

[The Doctor]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 09/09/2013 04:01 PM, Eugen Leitl wrote:

> Even cheaper: hang a cheap microphone into a fan exhaust. Noise
> definitely not white, but certainly more entropy than just looking
> at lowest bits of A/D.

I've been playing with one of these for a while with one of my netbooks:

https://www.sparkfun.com/products/11345

By default, the firmware running in the on-board microcontroller
records the time between three successive hits on the 'tube (t1, t2,
t3).  If (t2 - t1) < (t3 - t2), it prints a 0 to the serial port,
else, it prints a 1 to the serial port.  Hardly high resolution
entropy, but it can be stirred into an entropy pool.  New firmware
can, of course, be developed using the existing C code as a base.  I'm
not entirely certain how helpful or useful it is (I have my doubts, to
be honest), but if nothing else it's given me cause to do some reading
up and try a few small scale experiments.

- -- 
The Doctor [412/724/301/703] [ZS]
Developer, Project Byzantium: http://project-byzantium.org/

PGP: 0x807B17C1 / 7960 1CDC 85C9 0B63 8D9F  DD89 3BD8 FF2B 807B 17C1
WWW: https://drwho.virtadpt.net/

Your memories are fiction.

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.20 (GNU/Linux)
Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/

iEYEARECAAYFAlIvYZMACgkQO9j/K4B7F8EkFACffdFMYDo4n4b5o28SVwNGO6DJ
CS8An3uWoQfewFYBCmP+1xByr3yDxgH2
=/y/F
-----END PGP SIGNATURE-----