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.
-----BEGIN PGP SIGNED MESSAGE----- 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 - --------------------------------------------------------------------------- PGP 6.2.2 Key fingerprint: AA D0 F5 44 C1 8C 11 52 B3 80 34 1C CE 38 EC 53 Public key at: pgp-public-keys@pgp.mit.edu, and other popular key servers. - --------------------------------------------------------------------------- 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 - =========================================================================== -----BEGIN PGP SIGNATURE----- Version: 2.6.2 Comment: Auto-signed with Bryce's Auto-PGP v1.0beta iQCVAwUBMJ+5WqDthkLkvrK9AQFsgwP/UFHv+skRuUb/2V3QgUHmXcDe/dZfBZaZ d4A78fuixruhtpCU6dJKcfpUzyWz8Y+iYGll+bFiotJuX2xrSnYji2TbesWsp0AL XjczoLdG/V2RRQrx57R8Zdq33W6QFb/7j16NdXghLizvxUi5LVk6zRAakMhwa2FM 3+ywY6mgM2I= =dBcX -----END PGP SIGNATURE-----
participants (3)
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Bill Stewart -
Henry W. Farkas -
SINCLAIR DOUGLAS N