The Application Research Of Digital Watermarking Technology In Design Documents Management

With the development of network technology, lots of electronic documents are used in the internet,which causes many problems of the protection of copyrights and integrality of electronic documents.To solve those problems, digital watermarking technology is just an effective measure, which canavoid loss of tampering documents maliciously. Nowadays, digital watermarking technology ismainly used for the protection of copyrights and content authentication of documents, by the way ofembedding some watermark into digital products. This paper introduces digital watermarkingtechnology into the design documents management, building a security digital watermarkinghierarchy for those design documents, proposing a new algorithm to produce watermark informationand improving algorithms to embed and extract watermark. The main content of the paper is asfollows.(1) Describes a multilevel digital watermarking hierarchy whose core content is digitalwatermarking algorithm of documents. Because it cannot guarantee the security of documents in theinformation system that if we only use digital watermarking algorithm. This paper adopts thetechnology of RBAC (Role Based Access Control), improves several classic digital watermarkingalgorithms and classic digital watermarking protocol based on those existed ones. This security digitalwatermarking hierarchy solves the problems about the protection of copyrights and the security ofcontent better.(2) Proposes a new algorithm to produce the information of watermark. This algorithm getswatermark information through matrixing several times and then computing the Eigen value based onthe characters’ encoding with Unicode and location in the document. Some experiments’ resultsrepresent that this algorithm is useful to any type of character, enhance the system’s anti-Hollimanattack, is sensitive to malicious tamper and can be used to verify the uniqueness of the documents.(3) Proposes an improved algorithm to embed and detect watermark. Documents are mainlycomposed of the intersection between all kinds of lines, curve and straight line with smaller lengthand width. This characteristic is similar to that of binary image. Binary image is a special kind ofimage which is less redundancy and with simple texture and sensitive to distortion. So binary imagesare useful for the authentication of documents’ integrity and reliability. This paper embeds watermarkinto documents through partitioning the document image twice according to the similarity betweenbinary image and document. Firstly, we divided documents into some equal small blocks which are not overlap, then embed watermark into each image block under the condition of flipped pixels.Secondly, to improve the robustness of algorithm, the document which has been embed watermarkonce is divided into some equal larger blocks which are not overlap, then embed watermark into eachblock by the way of detecting edge. Some experiments’ results represent that this algorithm causesless distortion, can predict the possible location being tampered, improve the capacity of watermarkand guarantee the robustness.