Graph-based algorithmic techniques for watermarking using self-inverting permutations and bitonic sequences (Master thesis)

Μπαντή, Άννα


Over the last 25 years, digital or multimedia watermarking has become a popular technique for protecting the intellectual property of any digital content such as image, audio, video or software data. Software watermarking has received considerable attention and was adopted by the software development community as a technique to prevent or discourage software piracy and copyright infringement. A wide range of software watermarking techniques has been proposed among which the graph-based methods that encode watermark numbers as graphs whose structure resembles that of real program graphs. Following up on recently proposed methods for encoding watermark numbers w as reducible permutation flow-graphs F[ ] through the use of self-inverting permutations , in this thesis, we extend the types of flow-graphs available for software watermarking by proposing two different reducible permutation flow-graphs, namely, Fs[ ] and Ft[ ]. These flow-graphs incorporate important properties which are derived from specific properties of the bitonic subsequences composing the self-inverting permutation . We show that a self-inverting permutation can be efficiently encoded into either Fs[ ] or Ft[ ] and also efficiently decoded from theses graph structures. The proposed flow-graphs Fs[ ] and Ft[ ] enrich the repository of graphs which can encode the same watermark number w and, thus, enable us to embed multiple copies of the same watermark w into an application program P. Moreover, the enrichment of that repository with new flow-graphs increases our ability to select a graph structure more similar to the structure of a given application program P thereby enhancing the resilience of our codec system to attacks. Finally, we compare the proposed watermarking algorithms with two previously proposed codec watermarking algorithms and present similarities and differences with respect to their structures and complexity. In addition, we compute the probabilities of edge and label modifications of our flow-graphs Fs[π*] and Ft[π*] in order to consider the resilience of our watermark systems.
Institution and School/Department of submitter: Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Μηχανικών Η/Υ & Πληροφορικής
Subject classification: Permutations
Keywords: Υδατογράφηση,Μετάθεση,Γράφημα,Watermark,Permutation,Graph,Bitonic
URI: http://olympias.lib.uoi.gr/jspui/handle/123456789/27894
Appears in Collections:Διατριβές Μεταπτυχιακής Έρευνας (Masters)

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