From: tzeruch@ceddec.com
Date: Tue, 24 Jun 1997 06:06:24 +0800
To: Steve Schear <azur@netcom.com>
Subject: Re: Sources for stego images, was re: Laying PipeNet
In-Reply-To: <v03102804afd38b324730@[10.0.2.15]>
Message-ID: <97Jun23.180055edt.32257@brickwall.ceddec.com>
MIME-Version: 1.0
Content-Type: text/plain



On Sun, 22 Jun 1997, Steve Schear wrote:

> >That's the major problem with images, you need to generate your own.
> >Unless you fancy writing an image enhancement system, and analyse the
> >algorithms in existing systems to ensure that randomness is
> >introduced.
> >
> 
> There are plenty of Net-cams watching traffic or sunsets around the world.
> Since these images tend to change a bit from frame to frame they could
> cheaply and reliably provide the sorts of images which are ideal for stego.
> I'm not sure if you can frame-grab from such a changing Web page with the
> current browser features, but this should be a significant hurdle.

Or, set up your own webcam "to watch your coffee pot twice a minute" or
something. Merge the crypto stream through the gifs after tweaking the
brightness and contrast to avoid 0 and 255 (a light fixture with a pattern
of 254/255 values gets suspicious, and is not from thermal noise - a
"problem" with monochrome quickcams for night photography).

Then do something like

  lynx -source webcam.x.y/images/coffee.gif | destegodecrypt >>reconstruct

every 30 seconds (with some kind of dropout correction).  [lynx is a
textmode browser that works well for these types of things].

Or even an AVI for both video and sound stego.