H Function based Tamper-proofing Software Watermarking Scheme

A novel constant tamper-proofing software watermark technique based on H encryption function is presented. First we split the watermark into smaller pieces before encoding them using CLOC scheme. With the watermark pieces, a many-to-one function (H function) as the decoding function is constructed in order to avoid the pattern-matching or reverse engineering attack. The results of the function are encoded into constants as the parameters of opaque predicates or appended to the condition branches of the program to make the pieces relevant. The feature of interaction among the pieces improves the tamper-proofing ability because there being one piece destroyed, the program will not work correctly. The simulation shows that the performance of the proposed scheme is good and can resist many kinds of attacks.