Hi Eugene,
There are many parts of your recent comments which I disagree with, as
much as I understand them. Some of what you write isn't really clear
to me, and I don't feel like debating each point in detail.
However, here are a two points of clarification, regarding "Napster"
and my
As far as I know, all fielded watermarking schemes can be defeated
with simple, invisible distortions of the image - see
http://www.cl.cam.ac.uk/~fapp2/steganography/
for work done by Fabien Petitcolas and Ross Anderson. You don't even
have to have more than one copy of the picture or know
On Sat, 15 Jan 2000, Eugene Leitl wrote:
Joe Sixpack also doesn't believe that color laser copiers leave an
unique signature on each copy, allowing you to trace the copy to an
individual device. Nevertheless these are there, and can be evaluated
if need arises. (Just try distributing a few
Well, the deformations must be smooth, so this just describes an
attack against a certain type of watermarks.
As I said, it is difficult to resiliently watermark a single image.
Paul Crowley writes:
As far as I know, all fielded watermarking schemes can be defeated
with simple, invisible
Correct
Working for Xerox I can assure you that all of our colour machines together
with all our competitors colour machines leave a "trace".
I have seen this in action with respect to our Australian Federal Police
tracking down money printed on one of our machines.
Regards
AM
-Original
