Watermarking PDF Documents using Various Representations of Self-inverting Permutations

Abstract

This work provides to web users copyright protection of their Portable Document Format (PDF) documents by proposing efficient and easily implementable techniques for PDF watermarking; our techniques are based on the ideas of our recently proposed watermarking techniques for software, image, and audio, expanding thus the digital objects that can be efficiently watermarked through the use of self-inverting permutations. In particular, we present various representations of a selfinverting permutation π * namely 1D-representation, 2D-representation, and RPG-representation, and show that theses representations can be efficiently applied to PDF watermarking. Indeed, we first present an audio-based technique for marking a PDF document T by exploiting the 1D-representation of a permutation π * , and then, since pages of a PDF document T are 2D objects, we present an image-based algorithm for encoding π * into T by first mapping the elements of π * into a matrix A * and then using the information stored in A * to mark invisibly specific areas of PDF document T . Finally, we describe a graph-based watermarking algorithm for embedding a self-inverting permutation π * into the document structure of a PDF file T by exploiting the RPGrepresentation of π * and the structure of a PDF document. We have evaluated the embedding and extracting algorithms by testing them on various and different in characteristics PDF documents.

Research on a watermarking recognition method for PDF documents based on natural language processing

“…PDF documents have been widely used in various internal networks such as e-government networks and enterprise information networks, and security issues have become increasingly prominent 3 . Watermarking, as a technical means to  281097756@qq.com, lis54@hn.sgcc.com.cn, lizizun1996@qq.com, 517793054@qq.com, 860755845@qq.com, 1523302247@qq.com protect file security and prevent malicious theft by others 4 , is commonly used to protect internal confidential official documents and files.…”

Integrity Verification & Temper Detection of English Documents u si ng Hybrid Structural Component a nd Word Length

“…This procedure is defined through the following mathematical equations. means the pattern marking rate transition and state which is given in equation 1and (2). From the Markov matrix, weight of every state is calculated and then the pattern matching rate is calculated for the attacked and the original document.…”

“…The geometrical attack attacks the text documents that are watermarked based on the invisible watermark. The attacker needs knowledge about the technique that is used for watermarking or watermarking key to remove the watermark [2].…”