Research On Software Watermark Based On PE File

In recent years, with the development of computer communication technology and the popularization of the Internet, the dissemination of digital information and products has become more convenient and widespread. At the same time, software copyright protection has become issues requiring urgent solution. As a new technology of software copyright protection, software watermarking can be used to identify its author, publisher, owner, user, etc. Besides, it carries information of copyright protection and identification, thus it can identify those illegally copied or embezzled software products.PE file format is one of the mainstream file formats of Microsoft's Windows operating system. All executants of Win32 are stored on the disk in this format. Research work about PE file is mostly concentrated in the area of anti-virus, while research of software watermark is still in the initial stage. On this account, the following actions have been taken in this thesis.(1) On the basis of detailed analysis of PE file format, it further studies the redundancy of PE file and proposes an algorithm of software watermark, which is based on the replacement of instructions. By replacing the original instruction in the PE file and moving it into the section of structure code, this algorithm combines more closely the watermark with the original instruction and improves the watermark's imperceptibility and invulnerability.(2) Through the intensive study of the import table in PE file, based on which it proposes an algorithm and embeds the watermark taking advantage of the miscellaneous character in the import table in PE file. Moreover, it disguises the embedded information in accordance with the characteristics of the embedded characters, which improves the watermark's imperceptibility.(3) It also studies the structure of the import table in PE files, based on which it proposes another software watermark algorithm. This algorithm embeds the watermark into the carrier PE file, through the reform of the import table's structure. There's no need to add any extra data. The algorithm has good imperceptibility and invulnerability.(4) Referring to the matter of limited embedded information in each single carrier, algorithm of multi-file software watermark based on the import table is proposed. Through tracking back to the relation trees within the multiple files generated by the import table, and by storing the watermark distributed in multiple files, this algorithm increases the capacity of embedded information and has good imperceptibility and invulnerability.In this thesis, the above four algorithms have been shapes of algorithm system, each of which has been verified its feasibility and effectiveness.