Design And Implementation Of Electronic Documentcopyright Protection System

With the rapid development of computer and network technology, more and moreinformation is efficiently stored and transmitted through texts, images, audio, video andother information carriers. Electronic document is one of the most frequently andextensively used carriers in daily life and work. The widespread use of electronicdocument provides a great convenience for people, on the other hand, introduces manysecurity issues such like copyright disputes, illegal dissemination and malicioustampering. In order to protect the copyright and the authenticity of the content ofelectronic document, an electronic document copyright protection system is designedand implemented in this thesis based on digital watermarking technology by usingWord2007documents with Office Open XML format as information carriers.This system includes three main parts, they are watermark generation module,watermark embedding module, and watermark extraction module. The watermarkgeneration module generates copyright watermark information without encryption orusing one of three encryption algorithm. Watermark embedding module and watermarkextraction module use two watermarking algorithm with different functions. Firstwatermarking algorithm proposed in this thesis for Word2007is based on identifiermodification. Second is a novel algorithm based on space character. The first algorithmbrings no visual effects to document content and format, and has strong robustness onmodification of document content. The second algorithm could be used for the tamperdetection of contents of electronic documents, because the embedding of watermarkinformation relates to each text element. Watermark embedding module use twoalgorithm mentioned above to repeatedly embed copyright watermark information toelectronic document. Then electronic document with dual watermark is generated. Thewatermark extraction module authenticate the copyright holder through first copyrightwatermark information abstracted by first algorithm, then abstract second watermarkinformation. At last, these watermark information is compared. The document isintegrated if watermark information is accordant with each other. Otherwise, thedocument has been tampered. Experimental results show that, the system is stable andperforms well on copyright authentication and tamper Detection.