Digital Rights Management System Based On Digital Fingerprinting

Digital fingerprinting is a kind of copyright protection technique which embeds users'ID information into the multimedia copies in a secret way.When the proprietors find a leaking illegal copy,it can extract the ID from it and then trace the"traitor". The secret ID information here is the so-called digital fingerprint.In this paper, a digital fingerprinting algorithm based on characters' shifting aims at the PDF documents is introduced. The thesis introduces a set of rules of binary logic value corresponding to the shift of characters.Based on these rules, fingerprint is insert in the PDF user space according the Logistic chaotic map, so the embedding algorithm can accord with the Kerckhoffs principle. Meanwhile, two fingerprint extraction algorithms are described in this thesis. One is from PDF documents it-selves and the other is from the screen shot of pages in PDF documents.The later algorithm matches the feature points by SURF feature extraction and FLANN search , and uses pixel projection or contour searching to split the characters,finally, it achieves the characters shifting and the fingerprinting by create a coordinate system on the page and maps it to the PDF user space. This algorithm proved to have high practicability.This thesis also presents an image fingerprinting algorithm based on blocked DCT transition and detection of the complexity of the image. It describes the complexity of images with contour detection and the entropy of the gray-level co-occurrence matrix(GLCM), and extracts the blocks contains complex texture, then embeds fingerprinting in them. As a result, the transparency of fingerprinting can be increased. Also, the algorithm divides the fingerprint into many units. Each unit consists of two different parts, the header and the data. The header contains the position of the data part in the original fingerprint, so the data in all units can be restored in a whole fingerprint. Finally, based on Logistic chaos array, the units can be embedded in the chosen blocks which not only increases the robustness of the fingerprinting, but also accord with the Kerckhoffs principle. The experiments shows this algorithm is effective.The last part of this thesis is about an online digital rights management system based on anonymous fingerprinting protocol. The system sets up a third-party institution to manage users'ID information, and to create digital fingerprints with a salted SHA-1 algorithm. This system uses anonymous fingerprinting protocol to increase the safety and efficacy of the fingerprint, and protect the users' privacy.