Image Watermarking embeds a secret message into a cover message which discourages intellectual property theft and allows us to prove ownership in case of theft. Embedding a structure W (the watermark) into a program P such that: The embedding has a high data rate, cheap i.e. it does not adversely affect the performance of P and stealthy (does not change any statistical properties of P)
Two possible interpretations of stealth are static stealth and dynamic stealth. A watermark is statically stealthy if there are no statistical differences between the original and the watermarked program. Similarly, the watermark is dynamically stealthy if an execution trace of the program doesn’t differ.
Static Watermarking Techniques
Software watermarks are of two types, static and dynamic. Static watermarks are stored in the application executable itself. And have been around for a long time. Moskowitz and Cooperman and Davidson and Myhrvold are two techniques of static watermarks. According to Markowitz and Cooperman a static watermark is embedded in an image using one of the many media watermarking algorithms. This image is then stored in the static data section of the program. Whereas according to Davidson and Markowitz static code watermark a fingerprint is encoded in the basic block sequence of a program’s control flow graphs.
To detect the watermark of Venkatesan et al. The extractor needs to reconstruct the control flow graph of the watermarked program, identify which nodes of graph belong to watermark graph and reconstruct watermark graph itself.
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