Re: Video as a source of randomness

>>How useful would it be to use a video stream as a source of random input
>>to something like /dev/random?  I'm thinking along the lines of a
>>Connectix QuickCam (sp?) or the cool videocam that comes with the Indy.
>>It seems to me that the picture recieved by a camera sitting atop a
>>monitor would be quite unpredictable. (relatively) High bandwith, too.

Depends on what the camera's looking at - the first frame you grab may have
a lot of entropy, but if there's nothing much going on in the room, 
one frame's going to look a lot like the next.  Of course, pointing the camera
at your keyboard and taking a video of you typing in lots of random
numbers will probably produce better randomness than just timing the keys
while you do so...  But do move it away before typing in your passphrase...
Pointing the camera at a snowy TV or out the window or at a cat playing
with catnip can generate much more randomness if you need it.

Somebody was saying that of course not may computers will have video capture
devices on them, but it was probably one of those parochial PC or Unix geeks
who forget that Mac users get all the cool video/audio gear long before
the rest of us :-)
#---
#                                       Thanks;  Bill
# Bill Stewart, Freelance Information Architect, stewarts@ix.netcom.com
# Phone +1-510-247-0664 Pager/Voicemail 1-408-787-1281
#---

The cheapest strong source of video noise that I can think of would be
a small fan with a ribbon tied to the grille.  As long as it's in a
turbulent flow regime, you'll get very random numbers at a fast
rate.

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On Sun, 5 Nov 1995, SINCLAIR DOUGLAS N wrote:

> The cheapest strong source of video noise that I can think of would be
> a small fan with a ribbon tied to the grille.  As long as it's in a
> turbulent flow regime, you'll get very random numbers at a fast rate.

Oh, I don't know about cheapest.  Electricity costs money.  How does $.32 
per day sound to you?  I've come up with a successful algorithm that 
works like this: I generate a number based upon a random seed.  To get 
the seed, I mail a letter in exactly the same bin at exactly noon 
Monday - Saturday at the US Post Office on Orange Street in New Haven, 
CT.  The letter is always addressed to the exact same recipient.  I simply 
record the number of days it takes for the letter to arrive.  Guaranteed 
random.

===========================================================================
     Henry W. Farkas      |     Me?     Speak for IBM?     Fat chance.
 hfarkas@ims.advantis.com |------------------------------------------------  
   hfarkas@vnet.ibm.com   |     http://www.ims.advantis.com/~hfarkas
      henry@nhcc.com      |          http://www.nhcc.com/~henry 
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We'll just outlaw unlicensed cryptography.  After all, it works in France.
You don't see weekly terrorist attacks there any more do you?  - futplex -
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