Watermarking PDF Documents using Various Representations of Self-inverting Permutations

Maria Chroni, Stavros Nikolopoulos

2015

Abstract

Portable Document Format (PDF) documents are extensively used over the internet for information exchange and due to the ease of copying and distributing they are susceptible to threats like illegal copying, redistribution, and plagiarism. This work provides to web users copyright protection of their 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 self-inverting permutation p* 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 p*, and then, since pages of a PDF document T are 2D objects, we present an image-based algorithm for encoding p* into T by first mapping the elements of p* 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 p* into the document structure of a PDF file T by exploiting the RPG-representation of p* 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.

Paper Citation

in Harvard Style

Chroni M. and Nikolopoulos S. (2015). Watermarking PDF Documents using Various Representations of Self-inverting Permutations . In Proceedings of the 11th International Conference on Web Information Systems and Technologies - Volume 1: WEBIST, ISBN 978-989-758-106-9, pages 73-80. DOI: 10.5220/0005445800730080

in Bibtex Style

@conference{webist15,
author={Maria Chroni and Stavros Nikolopoulos},
title={Watermarking PDF Documents using Various Representations of Self-inverting Permutations},
booktitle={Proceedings of the 11th International Conference on Web Information Systems and Technologies - Volume 1: WEBIST,},
year={2015},
pages={73-80},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0005445800730080},
isbn={978-989-758-106-9},
}

in EndNote Style

TY - CONF
JO - Proceedings of the 11th International Conference on Web Information Systems and Technologies - Volume 1: WEBIST,
TI - Watermarking PDF Documents using Various Representations of Self-inverting Permutations
SN - 978-989-758-106-9
AU - Chroni M.
AU - Nikolopoulos S.
PY - 2015
SP - 73
EP - 80
DO - 10.5220/0005445800730080