Steganography is a “science”, the method of hiding sent information. Unlike cryptography that deals with coding of information, the main idea of steganography is hiding the fact that the message exists. It embeds the secret message in cover media (image, audio, video, text, etc.). During the last years with the development of digital image processing, methods of digital steganography have gained a lot of popularity. The most popular steganography method is LSB (Last Significant Bit) replacement in the cover image. With extensive evolution of steganography, Steganalysis methods have a lot of importance. Steganalysis algorithms role is to detect a hidden secret message inside any media. The most notable Steganalysis algorithm is the RS method [1], which detects stegamesage by the statistical analysis applied on image pixels.
Shen Wang and others [2] created a new algorithm based on Genetic Shifting method (GSM). GSM performs manipulation and modification of the original image pixels. GSM algorithm keeps image statistic after inserting a hidden message and is hard to be detected by the RS analysis. The goal of the project is to demonstrate effectiveness and stability of GSM algorithm against RS analysis by using mathematical and statistical methods.
Project presentation - Steganographic Application of improved Genetic Shifting algorithm against RS analysis - BScEE final assignment by Vadim Purinson, adviser Vladislav Kaplan MScEE
1. Steganography application of effective
Genetic Shifting Algorithm against RS
Analysis
Advisor: MScEE, Vladislav Kaplan
Vadim Purinson LV Tailoring Software
2. Who owns the information – owns the
world
Rotschild Nathan Mayer
• What is Steganography?
• Why Steganography?
• History of Steganography.
• Digital steganography.
• Steganalysis.
• RS Fridrich analysis.
• Genetic shifting algorithm.
• Software implementation.
• Tests
• Conclusions
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3. What is Steganography?
The art and science of hiding information by embedding it in some
other media.
• Steganography versus cryptography
• In general, steganography approaches hide a
message in a cover e.g. text, image, audio file,
etc.
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4. Why Steganography?
• Transfer secret information or embed secret
messages into media.
• Data, intellectual property and privacy
protection - Digital Water marking, medical
data.
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5. History of Steganography.
• 400 B.C. – writings of Herodotus
• 1499 – “Steganographia”, Trithemius –
steganography and magic.
• 1665 – Steganographica, Gaspari Schotti.
• 1870 – The Pigeon Post into Paris.
Most popular example in history this is use
invisible inks.
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7. Terminology and Definitions
• Steganographic system or stegasystem –
this is set of tools and methods are used to
generate a secret channel of information
transmission.
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8. Digital image definition
A digital image is binary representation of a two
dimensional image and contains a fixed number of rows
and columns of pixels.
• Pixel
• Byte
• Bit
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Equation 1
9. Message embedding
mathematical definition
8 bit Grayscale equivalents to 1 byte per pixel.
For example, for the image size of 7 Kbyte
maximum message size can be embedded, by
using 1 LSB is 7168 bit
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Equation 2
10. Digital steganography.
Advantages of digital images steganography is:
• There are a variety of methods used in which information can be hidden in
the images.
• Relatively large volume of digital images representation, that allows the
embedding of large amount of information.
• Known size of the cover media, that absence of restrictions, requirements
imposed by real-time.
• Presence of relatively large textural regions in most digital images that have
noise structure and well suited for information integration.
• Weak sensitivity of the human eye to minor changes the color of the image,
brightness, contrast and the noise presence.
• Image steganography has come quite far with the development of fast,
powerful graphical computers.
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11. IMAGE STEGANOGRAPHY TECHNIQUES
• Least Significant Bit insertion – LSB
• Masking and filtering
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16. The properties of the human eye
used in the steganography .
• selectivity to brightness fluctuations;
• frequency sensitivity;
• masking effect;
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17. Selectivity to brightness fluctuations
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Human eye sensitivity to
contrast.
Experimental data by Aubert (1865), Koenig and
Brodhun (1889) and Blanchard (1918). It
indicates that the Weber-Fechner law - according
to which the smallest perceptible change in
intensity ∆ 𝐼 vs. intensity level I is constant.
21. Stegattacks classes
• Attack with the knowledge of the modified media only.
• Attack with knowledge of unmodified container.
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The results of stegattack
• Detect secret message presence.
• Recover secret message from stegoimage.
• Destroy the message in case no possibility to recover
message.
23. Main methods of stegattack
• Visual analysis – detect visual image
degradation by “naked” eye.
• Statistical Histogram and STD analysis.
• Detection methods are based on data hiding
analyzing the characteristics of the probability
distribution of the container.
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28. Genetic Shifting Algorithm (Shen Wang )
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Before or After ?
𝐶 =
𝑖
𝑁
𝑖 + 1 − 𝑖
𝑁 − 1
𝑁 – this is number of pixels, and (𝑖 + 1) and
𝑖 are indicate current and next pixel values.
30. Front Panel
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Example of Front panel view
• Modern
• System
• Classic
• Express
• Control
Design &
Simulation
• .Net &
ActiveX
• Signal
processing
• Add ons
• User
Controls
• Select and
control
• DSC
Module
• RF
Communica
tions
• Sound &
Vibration
• Vision
Controls palette view
37. Steps definition
• Perform basic message coding (Cover Image) up to LSB-4 for gray images.
• Perform basic message recovery (Stego Image) up to LSB-4 for gray images.
• Compare visual image degradation.
• Compare visual degradation through common tools (Histogram, STD).
• Perform study of coded message saturation (message of different length) vs.
recovery and image degradation per different LSB coding at gray images.
• Build RS analysis (Fridrich algorithm) routine.
• Confirm validity of RS analysis on gray images.
• Implement secure genetic steganography method for RS baseline shifting
for LSB-1. (GSM for RS shifting).
• Perform basic message recovery with GSM for RS shifting for LSB-1.
• Perform RS analysis comparison for different message length with GSM for
RS shifting and without, use different “snake” division array image
representation.
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38. Compare visual image degradation
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LSB-1
The recovered text file size is 6.21 KB
(6,361 bytes), 1177 words text,
equivalent to 2.5 pages in WORD
format.
40. Compare visual image degradation
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LSB-2
The recovered text file size is 12.4 KB
(12,737 bytes), 2228 words text,
equivalent to 5 pages in WORD
format.
41. Compare visual image degradation
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LSB-3
The recovered text file size is 18.6 KB
(19,106 bytes), 3317 words text, equivalent
to 7.5 pages in WORD format.
42. Compare visual image degradation
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LSB-4
The recovered text file size is 24.8 KB
(25,477 bytes), 4468 words text,
equivalent to 10 pages in WORD format –
this is a maximum text file size can be
imbedded into 225 × 225 𝑝𝑖𝑥𝑒𝑙𝑠 image by
using 4LSB plane.
44. Compare visual degradation through
common tools
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Different depth of the LSB
Blue line is displays Cover
image Histogram and red line
represents manipulated image
distribution.
45. Compare visual degradation through
common tools
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Histogram degradation trough of
message enlargement for 4LSB level