Digital

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Digital Watermarking
Thái Chí Minh Tr?n Luong Khiêm
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Content

• Introduction
• History
• Applications
• Requirements
• Techniques
• Attacks

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Content

• Introduction
• History
• Applications
• Requirements
• Techniques
• Attacks

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Introduction
499.99 0.99
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Introduction
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Introduction
Digital watermarking
Steganography
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Introduction
Digital watermarking
Relation between embedded message and cover work
Goal and assumption
Steganography
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Content

• Introduction
• History
• Applications
• Requirements
• Techniques
• Attacks

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History
Histiæus the slave
Paper watermark, 1282
Banknote. 18th century
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History

• In 1954, Emil Hembrooke of the Muzak Corporation
  filed a patent for watermarking musical Works
• The first Information Hiding Workshop (IHW)
  ,which included digital watermarking as one of
  its primary topics, was held in 1996

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Content

• Introduction
• History
• Applications
• Requirements
• Techniques
• Attacks

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Applications

• Broadcast monitoring
• Owner identification
• Proof of ownership
• Transaction tracking
• Content authentication
• Copy control

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Broadcast monitoring
Advertisement
Rebroadcasting
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Owner identification
Original
Lena Soderberg, 1972
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Proof of ownership
Bob
Alice
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Transaction tracking
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Transaction tracking
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Content authentication

• Digital signature is NOT enough

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Content authentication
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Copy control

• Cryptography is NOT enough

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Copy control
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Content

• Introduction
• History
• Applications
• Requirements
• Techniques
• Attacks

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Requirements

• Perceptual Transparency
• Robustness
• Data payload
• With / Without originals
• Security

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Perceptual Transparency
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Robustness

• Fragile
• Semi-fragile
• Robust

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Data payload

• Data payload refers to the number of bits a
  watermark encodes within a unit of time or within
  a Work
• Different applications may require very different
  data payloads

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With / Without originals

• Non-blind watermarking
• Type I
• Type II
• Semi-blind watermarking
• Blind watermarking

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Security
(Present later)
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The mutual dependencies among the elements
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Content

• Introduction
• History
• Applications
• Requirements
• Techniques
• Attacks

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Techniques

• LSB
• Spread spectrum
• Applying on Vietnamese documents

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Techniques
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Techniques

• There are many techniques to do watermarking in
  digital things
• Spatial domain watermarking LSB, in text data,
• Transform domain watermarking frequency-based
  watermarking, wavelet based watermarking
• Embedding the watermark in the transform domain
  from carrier object (using DCT, DFT, DWT, )

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Techniques

• LSB
• Embedding
• Choosing some representation values (e.g pixels)
  of carrier object.
• Embed the bits of message (watermark) to LSBs of
  representation value
• Message A 100 0001
• Carrier object RGB (2 bits)
• 100000 010101 101100
• 010001 100001 000100
• 101110 011010 111000

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Techniques

• LSB
• Embedding
• Choosing some representation values (e.g pixels)
  of carrier object.
• Embed the bits of message (watermark) to LSBs of
  representation value
• Message A 100 0001
• Carrier object RGB (2 bits)
• 100001 010100 101100
• 010000 100001 000100
• 101111 011010 111000

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Techniques

• LSB
• Detector
• Retrieve the watermark by having the knowledge of
  the representation values (e.g pixels) used for
  embedding individuals bits

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Techniques

• Spread spectrum
• Using frequency domain transform to convert the
  input image into another domain and embedding the
  watermark to this domain.

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Techniques

• Apply on Vietnamese documents

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Techniques

• Apply on Vietnamese documents

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Techniques

• Apply on Vietnamese documents
• Besides, we can use some methods
• Vertically shifting text lines
• Horrizontally shifting words

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Content

• Introduction
• History
• Applications
• Requirements
• Techniques
• Attacks

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Attacks

• From processing
• From attackers

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Attacks

• The actions take effect on the watermark embedded
  in carrier objects.
• Affects
• Destroying the watermark or modifying the
  watermark with new wrong information.
• Removing the watermark entirely.
• But not degrading the quality of carrier objects
  (image, audio, video)
• Relating to a requirements of watermarking
  Robustness

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Attacks

• Classification
• From proscessing carrier objects
• Common signal processing digital-to-analog and
  analog-to-digital conversion, or change image
  contrast, color, JPEG compression,
• Common geometric distortions scaling, rotating,
  cropping, dithering
• From attacker
• Mosaic
• Collusion attacks get the watermark or remove
  watermarks entirely to get the original work.

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Attacks
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Attacks
Mosaic attack
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Attacks

• How to protect watermarks from attacks
• Understanding and applying new researchs in
  watermarking
• Using StirMark Benchmark evaluation engine to
  evaluate your watermarking scheme
• All vendors of digital watermarks have their
  products benchmarked by Stirmark and as of August
  2001, no watermark from any vendor survives the
  test, ie the watermarks are all removed without
  degradation to image quality occurring.

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Questions Answers
Thank you