Day by day, the digital watermarking is becoming a promising technique to protect digital data. It has seen numerous novel article covering new techniques; each one of those techniques have there advantages and inconveniences. In recent years, the techniques using linear algebra has attracted attention of researchers to use it for watermarking(e.g. SVD).

1. Protection of digital watermarking,
based on SVD against false positive
detection vulnerability
UNIVERSITY HADJ LAKHDER -BATNA-
SCIENCES FACULTY
COMPUTER SCIENCE DEPARTEMENT
By: Belferdi Wassila
Dr Behloul Ali
INTERNATIONAL CONFERENCE ON
ADVANCED COMMUNICATION AND
INFORMATION SYSTEMS

2. Plan
• Introduction:
• Singular Value Décomposition:
• False Positive Détection Vulnerability:
• Proposed Method:
• Sharing Secret Principle:
• Experiment Results :
• Robustness Conditions Of The Proposed Method:
• Conclusion and perspectives:
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3. Introduction
• Day by day, the digital watermarking is becoming a
promising technique to protect digital data.
• It has seen numerous novel article covering new
techniques; each one of those techniques have there
advantages and inconveniences.
• In recent years, the techniques using linear algebra
has attracted attention of researchers to use it for
watermarking(e.g. SVD).
3

4. • From the viewpoint of linear algebra we can observe that.
a discrete image is an array of non-negative scalar entries
which may be regarded as a matrix.
M=USV’=S li UiVi
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Singular Value Décomposition (1)
M U S V’
m
n
=
m r
n

5. 5
SVD Based Watermarking Example
Watermark
Hôst image
Uw
Sw
Vw
U
S
V
Insertion of
watermark in
hôst image
Watermarked
Image

6. False Positive Détection Vulnerability
• Duo to the watermark insertion method, another
watermark rather than the original can be reconstructed as
the embedded watermark; causing the false positive
detection vulnerability .
• If an attacker use U* and V* matrices of his own
watermark in place of reserved ones he can show his own
watermark.
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7. False Positive Détection Vulnerability (2)
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8. Proposed Method
• To avoid that an attacker reconstruct his watermark
using their own matrices U* and V*; the idea is to share
a secret key D between matrices Uw, Sw and Vw of
watermark.
• During the embedding phase, for each matrices Uw, Sw
and Vw of watermark a key is inserted, then use the
modified S* to reconstruct the watermarked image,
those keys are calculated using sharing secret principle.
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9. Sharing Secret Principle
• The goal is to divide a secret key D into pieces.
• The coefficients a1... ak-1 are randomly chosen from a uniform
distribution over the integers in [0, p-1]
• Pick a random k-1 degree polynomial q(x)=a0+alx+ . . . ak-1xk-1
in which a0=D.
• The values D1,..., Dn are evaluate:
D1= q(1) ,..., Di = q(i) ,..., Dn = q(n).
• Given any subset of k of these Di, we can find the
coefficients of q(x) by interpolation, and evaluate D=q (0).
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10. Embedding Phase
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11. Extraction Phase
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12. Experiment Results
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Robustness results of the proposed method against attacks
Attacks We W*e |D-Dc| |D-D*c|
Cropping 5 188037
Gaussian
noise 5 1888037
Rotation
0,2° 46568 234611
Resizing
44095 232139
Contrast
adjustment 425 188469

13. 13
Experiment Results(2)
the size
of
image
We W*e |D-Dc| |D-D*c|
512×512 5 188037
256×256 36 188007
128×128 913 187131
64×64 2406 185638
Results of the influence of image size on the robustness of the proposed method

14. Robustness Conditions Of The Proposed
Method
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• In the SVD, the biggest
part of energy is
concentrated in low
frequencies of images,
the watermarking profit
this property to insert
watermark in low and
middle frequencies
according to
robustness/invisibility
compromiser
influence of the inserted secret on the quality of the watermarked image

15. Conclusion
• The novelty of our scheme is the use of the sharing secret
principle in watermark embedding, that is adaptively chosen
according to the local features of the image.
• The aim of our solution is to hide the watermark and insure
their robustness against the false positive detection
vulnerability.
• The experimental results obtained give evidence that our
scheme is robust against several attacks.
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16. Perspectives
Our perspective turns around:
• increasing the robustness of our solution using block based
SVD scheme.
• Conceive a méthode to choose coefficients a1... ak-1 randomly
to obtain better results.
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17. QUESTIONS ?
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