digital watermarking

							    DIGITAL WATERMARKING
            A   T E   C H N O L O G Y   O   V E R V I E W




                                  www.tech-desire.blogspot.com




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                                              Overview
•   Introduction
•   Definitions
•   Digital Watermarking Techniques
•   Features of Digital Watermarking
•   Classification of Digital Watermarking Techniques
•   Applications of Digital Watermarking
•   Conclusion

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                                                            Introduction
• Internet
• Intellectual Property Rights
• Digital Rights Management
            • Describing, identifying, trading, protecting, monitoring and tracking IP
              rights
            • Addresses content identification, content storage, content representation,
              content distribution and IP rights management
• Digital Watermarking
            • Establishing ownership rights, tracking usage, ensuring authorized access,
              preventing illegal replication and facilitating content authentication




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                                                       Definitions
• Watermarking
            • Concealing information inside documents without affecting
              their perceived quality
            • Rooted in Steganography
• Steganography
            • a technique where a secret message is hidden within another
              unrelated message and then communicated to the other
              party.
• Digital Watermarking
            • Similar to watermarking
            • a low-energy signal is imperceptibly embedded in another
              signal

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      Difference between
Steganography and Cryptography
• In Cryptography,the content of a communicated
  message is secret.
• In Steganography,the very existence of the
  message that is communicated is a secret and its
  presence is known only by parties involved in the
  communication.




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                    Digital Watermarking

                                    Noise                Attacks
                  Watermark                                             Watermark
                  Key                                                   Key
Cover
Signal       Watermark             Communication                   Watermark    Watermark
             Embedder                Channel                        Detector


                  Watermark
                  Signal




                              Digital Watermarking Systems

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                                Digital Watermarking
                                                   T E   C   H   N   I Q   U   E   S




• General Procedures or schemas

            • Watermark Insertion

            • Watermark Extraction




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                                Digital Watermarking
                                                   T E   C   H   N   I Q   U   E   S




• Watermark Insertion
            • Cover (data/image) / hiding Medium
            • Watermark Symbol
            • Watermark key




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                      Digital Watermarking
                                         T E   C   H   N   I Q    U   E   S




                                 Watermark
                                 Key
            Cover
            Signal        Watermark                              Watermarked
                          Embedder                               Image


                                 Watermark
                                 Signal




                     Watermark Insertion

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                               Digital Watermarking
                                                  T E   C   H   N   I Q   U   E   S




• Watermark Extraction
            • Watermarked Data
            • Public or Private Key
            • Depending upon technique used original image may be
              needed




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                            Digital Watermarking
                                               T E   C   H   N   I Q    U   E   S




                                       Watermark
                                       Key
            Watermarked
            Image               Watermark                              Watermark
                                 Detector




                          Watermark Extraction

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                                              Features
•   Imperceptibility
•   Robustness
•   Inseparability
•   Security




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                                  Features
• Imperceptibility
            • Embedded watermarks are imperceptible and do not alter aesthetics of
              multimedia contents
• Robustness
            • Supports different level of robustness against changes made to the
              watermarked content
• Inseparability
            • Separating the content from the watermark is not possible
• Security
            • Prevents unauthorized users from detecting and modifying the watermark
              embedded in the cover signal

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                    Digital Watermarking             T E   C   H   N   I Q   U   E   S




• Least Significant Bit Technique (LSB)
            • A simple technique
            • In this lower order bits of selected pixels in the image are
              used to store watermarks




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                Classification              of   Digital Watermarking Techniques




•   Robust & Fragile Watermarking
•   Visible & Transparent Watermarking
•   Public & Private Watermarking
•   Asymmetric & Symmetric Watermarking
•   Steganographic & Non-Steganographic




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                                                        Classification
                                                        of   Digital Watermarking Techniques




• Robust & Fragile Watermarking
            • In Robust Watermarking technique, modification will not affect
              the watermark content
            • In Fragile watermarking, watermarking is destroyed when
              content is modified or tampered
• Visible & Transparent Watermarking
            • Visible watermarks are embedded in contents in such a way
              that they are visible when content is viewed
            • Transparent watermark are imperceptible and cannot be
              detected by just viewing the content

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                                                        Classification
                                                        of   Digital Watermarking Techniques




• Public & Private Watermarking
            • In Public watermarking, users are authorized to detect the
              watermark
            • In private watermarking, the users are not authorized to detect
              the watermark
• Asymmetric & Symmetric Watermarking
            • In asymmetric watermarking, different keys are used for
              embedding and detecting the watermark
            • In symmetric watermarking, same key is used for embedding
              and detecting watermarks

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                                                       Classification
                                                       of   Digital Watermarking Techniques




• Steganographic & Non-Steganographic
            • In Steganographic watermarking, content users are unaware of
              the presence of a watermark
            • In Non-Steganographic watermarking, users are aware of the
              presence of a watermark




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                Applications
•   Copyright Protection
•   Copy Protection
•   Tracking
•   Tamper Proofing
•   Broadcast Monitoring
•   Concealed Communication



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                                                        Applications
• Copyright Protection
            • Used to identify and protect copyright ownership
• Copy Protection
            • Content can be watermarked to indicate that the content
              cannot be illegally replicated
• Tracking
            • Watermarks can be used to track the usage of digital content
            • Watermarking technique used for this is called as
              fingerprinting

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                                                        Applications
• Tamper Proofing
            • Watermarks with fragile nature are used for tamper proofing
            • Watermarks get destroyed whenever any sort of modification
              is done
• Broadcast Monitoring
            • Can be used to monitor broadcasted content like television
              and broadcast radio signals
• Concealed Communication
            • Can be used for concealed communication also

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                                                Conclusion
• Digital Watermarking is the technique of choice for Digital
  Rights Management Systems for future e-Commerce
  Applications with Internet Distribution
• Digital watermarking have a huge potential in consumer
  electronics industry
• There is a legal complications and widespread
  disagreement about the scope of IP rights
• There may be advanced attacks against Digital
  Watermarks… The Research continues…


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