Hash Function Based Software Watermarking

Software piracy is the greatest threats to software industry, which will bring serious damages to the interests of software developers or providers. As a prevention technique, software watermarking is a new research area that aims at providing copyright protection for commercial software. This article proposes a hash function based dynamic software watermarking algorithm. By constructing appropriate hash function, watermark piece is embedded into it. Given the satisfied parameters, hash function will calculate out the corresponding watermark. To strengthen the logical relation with the program itself, some of the programpsilas constants are replaced by specific level hash function, tampering of watermark will lead to the applicationpsilas undefined behavior. Distinguishing from other watermarking techniques, this kind of watermark is not hidden inside the program code or its runtime state, but is calculated out dynamically. Analysis shows that this algorithm will be able to withstand a variety form of attacks.