Covert watermarking of digital documents

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master_Zaheer_Jawad_2024.pdf (13.6 MB)

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Volume Title

School of Science | Master's thesis
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Date

2024-09-02

Department

Major/Subject

Security and Cloud Computing

Mcode

SCI3113

Degree programme

Master's Programme in Security and Cloud Computing

Language

en

Pages

83

Series

Abstract

Covert watermarking is a security and privacy-related technique for subtly embedding a concealed identifier into a digital document that is not easily perceptible to human senses but can be retrieved by those with the right tools and knowledge. In this study, we use this technique to watermark personalized copies of PDF and printed documents to track information leaks online. This is to discourage the unauthorized sharing of company-confidential memos, documents with customers' personal information, etc. The study involves surveying existing tools, devising a robust watermark method, and embedding bit strings into documents through spacing modifications. Evaluation includes comparing original and modified documents, detecting encoded information, and measuring the accuracy and error rate by comparing Levinshtein distance. Furthermore, strategies are proposed to ensure the watermark’s resilience against printing-and-scanning, and screenshotting.

Description

Supervisor

Aura, Tuomas

Thesis advisor

Dragoni, Nicola

Keywords

watermarking, steganography, information hiding, encoding, decoding, image processing

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Citation

Permanent link to this item

https://urn.fi/URN:NBN:fi:aalto-202411207209

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[dipl] Perustieteiden korkeakoulu / SCI