Research On Java-based Software Watermarking And Interrelated Technique

As far as software watermarking interrelated technology is concerned a software watermarking based on constant reorder for Java is proposed firstly. Secondly, to combine with the idea of program decomposition, a kind of Java software birthmark is proposed. Finally, on the basis of software birthmark, a software watermarking based on code obfuscation is proposed. The main research conents and originality of this thesis can be summarized from three aspects in detail as follows:(1) By analyzing the structure of class file which can be the executived by Java Virtual Machine, the data redundancies of constant storage and usage regulation are found. By embedding the watermarks into these redundancies, a kind of Java software watermarking algorithm based on constant reorder is proposed. The algorithm embeds information through reordering the indexes of constant. The process of embedding does not embed additive data to the program, consequently it will not change the size of program, and it will not affect the performance of the program.(2) The existing k-gram software birthmark algorithm is to split the sequence of program instructions by equal length. This mechanical splitting can't embody the semantic of the program. Aiming at this disadvantage of k-gram software birthmark, a birthmark based-on Program decomposition for Java is proposed. By analyzing the virtual machine instructions, the instruction dependence by data processing is acquired. Combining with the program decompose technology, program instructions are splitting by unequal length, and the set of fragment of the program which can be the birthmark of the software is acquired. The birthmark can reflect semantics of the program, and resist the attacks of code reordering, appending additive code and so on.(3) On the basis of the proposed software birthmark, a Java software watermarking algorithm combining with the technology of obfuscation is proposed. According to code obfuscation and software watermark are both the semantics-preserve transformation, The two protection methods are combined with each other efficiently in the dissertation. The algorithm coding the watermark into sequences of instructions firstly. It uses the obfuscation technology to embed the sequences into the fragment of program, and it has moderately high robustness.Finally, the research work of this thesis is summarized, and the future developing direction of the software watermarking technologies is indicated.