[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 themselves. 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++ Cheers, Max 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?
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