Research Of Dynamic Graph Software Watermarking Algorithm Based On Tamper-proofing

With the rapid development of software industry, the copyright protection of software products already becomes a very important issue. Nowadays, so various technologies for software copyright protection have been studied. Traditional software copyright protection is mainly use the encryption technology. But with the development of software cracking technology, this methods can’t be avoid to crack, and the encryption technology can’t provide further protection after software decrypted. Software watermarking is an important branch of the digital watermarking technology. The copyright information and user information of the software products is stealthily embedded in the software. It proves the ownership of intellectual property rights when piracy occurred. Software watermarking make up for the lack of traditional software copyright protection, and provides a new way for copyright protection.Software watermarking can be classified as static watermarking or dynamic watermarking. Dynamic watermarking is robustness, superior to static watermarking, so it becomes a hotspot in this field. Dynamic Graph Watermarking (DGW) is one of the better dynamic watermarking. The idea of DGW is using of the graph topology structure, the software products copyright information can hide in the graph, this provides technical support to prevent software piracy and tampering.Firstly, this paper introduces the generation of dynamic graph software watermarking, the process of extraction and the embedded watermarking, the encoding methods and some relevant algorithms. By studied the dynamic graph watermarking algorithm, a double software watermarking scheme based on tamper-proofing is put forward for improving the low resilience and encoding data rate of software watermarking. With the stealth of register allocation to make ICP algorithm; combined the high data rate of radix-k encoding with the high resilience of PPCT encoding to make DPPCT mix encoding; after the watermarking embedded, using checksum mechanism and AES code encryption to prevent reverse engineering and some other methods to attack the software watermarking. Theoretical analysis and experimental result show that this scheme has high stealth, robustness, resilience and data rate.Secondly, through the chaos theory, a sharing software watermarking scheme based on chaotic optimization is proposed, in order to solve the poor robustness of software watermarking and the low execution efficiency of watermarking sharing algorithm. The scheme takes advantage of chaos system, generating chaotic sequence, matrix partition and chaotic scrambling the watermarking information to form sharing watermarking; when watermarking is embedded, using DPPCT topology graph encode the sharing watermarking, then putting the hash value of the watermarking information into the Info field of each DPPCT; after the watermarking embedded, using chaotic encryption to protect all code and prevent reverse engineering and other methods to attack the software watermarking. Theoretical analysis and experimental results show that the scheme can effectively improve robustness and execution efficiency of the watermarking.Finally, combined SandMark software watermarking platform, design a software watermarking prototype system, experiment on the proposed watermarking schemes, and objective analysis the watermarking performance, the result verifies the feasibility, robustness and superiority of the schemes that proposed.