Dependency in software watermarking

The advent of bytecode languages such as Java and advances in decompilation tools has made it easier to infringe the copyright of software. This presents a serious challenge to the software industry, as modern Internet software is highly distributed and the potential for software piracy is immense. Software watermarking has been proposed as one means of protecting the intellectual property in software. The strategy is to embed secret ownership information (i.e., a ´watermark´) in a program that cannot be easily removed by unauthorized parties but that can be reliably extracted by an authorized decoder. We investigate a practical implementation of dynamic graph watermarking, focusing particularly on embedding stealthy watermark generating code in the program´s text. Our scheme is based on the premise that watermarking code should not be distinguishable from ordinary program code. This is because one strategy for an attacker whose goal is to destroy the watermark is to attempt to directly locate the watermark generating code within the program text and remove or alter it.