[Cryptography] The ultimate random source

[Christian Huitema]

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

>> I have a solution to the random number generator problem that can be built for about $50 and is completely verifiable. 
>
> It works just as well, perhaps better, if you put a lens cap on the camera. The ritual with the smarties just makes you feel better.

If you rely on a capped camera to generate white noise, you may be out for a surprise with at least some cameras. There is a lot of filtering and processing that happens on board the camera itself, e.g. conversion from Bayer pattern to YUV or RGB, firmware that enhances the image, compression to JPEG before transmission on the USB bus, cropping and resizing on demand, etc. I would not be surprised if some cameras, when capped, just transmit a black image. 

The  camera is designed to produce an image that represents the scene in front of it. There are two sources of randomness that are "built in," the randomness of the scene itself, and the randomness of the position of the camera in the scene. A few degrees cause a lot of pixels to shift, a live scene has lots of varying bits. I would rather rely on that instead of making assumptions on the amount of filtering built in the firmware.

- -- Christian Huitema
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.20 (MingW32)
Comment: Using gpg4o v3.2.34.4474 - http://www.gpg4o.de/
Charset: utf-8

iQEcBAEBAgAGBQJTBFiTAAoJELba05IUOHVQJzEIAIDtPf5KmKQblLT/Em5xZ58c
Op6T57fu0ifNlvpx/eNkdpKDW8ZfCRD5pOOIKxrVW5fUNd4ZvyG+kn7UaOKqjLKX
LX/4vccjYSg0xesuB2fUIz12QP644FI+nRmo9XOvZWTyTwn2H99Q8eR4Y4ylKAkh
Lw6drL8/iC2e7eB7WRztzMAM2Nd/8R26XsRywauGvqjJ9ywGXp4Ygzd+GtSAvh+E
lsgWncoljI+qKqFXYB527jk8PxHDLvXYb0mMMkJfvOjV3F7VbWk/OUPlienXpy0S
gWjxZa9QOV3zUlTzUF5DiWCWypmeH883pQwWmJv58BheMFwPwsC8XJJiqVW3SWs=
=fO1w
-----END PGP SIGNATURE-----