[Moderator's note: Please no top posting. --Perry]

Hello Sandy, all,

basically what I need is a library that will allow me to check for
a watermark into an image/video/etc. It could be different algorithms
for different media type - my work is not related to the algorithms

The important issues are:
* the algorithm(s) should be based on public key (asymmetric)

* my program should be able to verify that a watermark exists and
   has been generated with a private key corresponding to a specific
   public key

* an attacker should not be able to add a watermark that my app
   would recognize as valid (ie., the verification would fail when
   using my app's public key if an attacker tries to substitute
   the watermark)

* if the watermark is removed/altered/substituted I should be able
   to detect it

* the watermark should be invisible

Do you know if/where can I find some libraries that provides me with
some implementation of one or more algorithms that satisfy my needs ?
I know there are a lot of publications about these algorithms, but
I need a usable (also if not perfect) implementation.. preferably
written in C/C++


On 04/20/2010 09:49 AM, Sandy Harris wrote:
What are your threat model and goals for the watermarking?

Some watermarks -- like the photographer's copyright notice across
a web picture -- are designed to be extremely visible. The whole
idea is that if anyone steals the photo, everyone will know.

For other threats, you might want a watermark to be completely
invisible, perhaps even undetectable without some sort of key.

Does it need to be tamper-resistant or unremovable?


Best Regards,

        Massimiliano Pala

Massimiliano Pala [OpenCA Project Manager]                   ope...@acm.org

Dartmouth Computer Science Dept               Home Phone: +1 (603) 369-9332
PKI/Trust Laboratory                          Work Phone: +1 (603) 646-8734
People who think they know everything are a great annoyance to those of us
who do.
                                                           -- Isaac Asimov

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