A Dynamic Graph Software Watermarking Algorithm Based On Chaotic Theory

With the rapid development of Internet and computer technology, the software piracy and crack are becoming increasingly serious. Therefore, how to effectively solve the copyright protection of software products to prevent piracy has become urgent to be addressed in the field of software security questions.At present, there are two kinds of technologies in software protection: encryption and information hiding. In information hiding field, there are three kinds of technologies for software protection: code obfuscating, tamper proofing and software watermarking. Software watermarking is a new method used to protect the copyright of software. It not only dependent on encryption techniques, software watermarking embeds certain secret information into host software codes to prove the software copyright. Software watermarking can be divided into static software watermarking and dynamic software watermarking according to the loading time. Static watermarks are easy to construct and identify, but it's relatively poor performance of attack-resistant, and dynamic software watermarking technology has a strong attack-resistant.This paper studies the current software watermarking technology detailed and put forward a new scheme which a dynamic graph software watermarking algorithm based on chaotic theory for the shortcoming of weak robustness of software watermarking. The theory used the dynamic map thought of software watermarking, in order to improve watermark information hidden in the program, the watermark information for embed software is separated into n numbers of small watermark information with the Chinese Remainder Theorem at first, and then watermark information can coding into a topological graph structure, Encoding method use the PPCT enumeration encoding and Robustness is best. Finally, the code to building sub-topology was hashed to the entire program code by chaotic system, It can protect the entire program code and improve the watermark robustness. In the extracting procedure the user inputs secret key, the corresponding topology graph is created in the memory, and then uses the decoding algorithm to restore the watermark information from the structure of map to prove their copyright. On the performance of the watermark algorithm, the main work is as following: (1) analyzed the stealthiness, data rates, attack-resistant and so on; (2) divided watermark information into different parts of sub-watermarks, and analyzed different data of time; ( 3 ) made the experiments on the execute time, code space and the embedded efficiency and made comparison with CT algorithm. The experiments indicated it's robustness and stealthiness are stronger, and it is more practicable.