Re: Digital Watermarking query

New Message Reply About this list Date view Thread view Subject view Author view

Marty Levy (rwww60@email.sps.mot.com)
Fri, 03 Apr 1998 07:49:53 +0100

Please excuse me if this is a dumb question, I couldn't find it in
the FAQ and I'm a bit of a newbie.
I have a desire to use watermarking in the following way, and would
appreciate any pointers:

I want to distribute .pdf files to various people and have them be
"watermarked" (traceable to the person I sent them to in a non-
repudiable fashion). I believe Acrobat uses 40 bit RC4 encryption to
"protect" the files (which don't contain .gif or .jpg images
suitable for steganography). My main concern is that I don't
want the files to be distributed beyond the recipient (such as
posted on the internet), and I want to be able to trace them
back to the source if they are.

Q. Is Acrobat's instantiation of 40b RC4 reasonably difficult to break?
Q. If not, is there any watermarking method likely to allow me to
keep traceability?

           Thanks,

           Marty Levy

Mordechai Ovits wrote:

> Nicholas Charles Brawn wrote:
> >
> > 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.
> >
> > regards,
> >
> > Nicholas Brawn
>
> There is an interesting site that contains useful info on cracking
> stego. Here is the URL:
> http://www.fravia.org/stego.htm
> The site contains several ways of breaking stego/watermarking. The most
> interesting to me was the one where Digimarc's code was reverse
> engineered and altered so that you were free to put your own copyright
> on previously copyrighted images. The URL for that is:
> http://www.fravia.org/frogdigi.htm
>
> Also, make sure you check out the work done on Unzign and Stirmark and
> the links at the bottom of the stego page.

New Message Reply About this list Date view Thread view Subject view Author view

 
All trademarks and copyrights are the property of their respective owners.

Other Directory Sites: SeekWonder | Directory Owners Forum

The following archive was created by hippie-mail 7.98617-22 on Fri Aug 21 1998 - 17:16:50 ADT