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The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:16:49 ADT
Peter Wayner (pcw@access.digex.net)
Wed, 1 Apr 1998 08:59:26 -0500
>I seem to recall that a digital watermarking product was
>released a short
>while ago, and a succesful attack against it was published soon
>afterwards. Can anyone remember the attack I am referring to? And
>if so could you point me towards further information.
>
One major system is the Digimarc system which is built into new
versions of Adobe Photoshop. It embeds information by using some
sort of Fast Fourier Transform device. It's somewhat robust
because you can crop or blur an image to some extent and still
recover the watermark. I've discovered, however, that one way to
destroy it is to rotate by 45 degrees, blur twice, sharpen twice
and rotate back. My eyes don't notice the degradation, but maybe
yours would.
This was included in the back of my book, _Digital Copyright
Protection_, published by AP Professional and available from,
among others, http://www.amazon.com/
-Peter
pcw@digex.net
>regards,
>
>Nicholas Brawn
>
>--
>Email: ncb05@uow.edu.au
>Nicholas Brawn - Computer Science Undergraduate, University of
>Wollongong.
The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:16:49 ADT