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--- security:steganography [2011/12/29 01:57] – cedric
+++ security:steganography [2016/07/05 13:01] – cedric
@@ Line 1: / Line 1: @@
+====== Installation of Stéganô ======
+For the examples you need to install Stéganô.
+<code bash>
+sudo pip install Stegano
+</code>
+You can read the [[http://stegano.readthedocs.io | documentation of Stéganô]] (included in the sources).
 ====== Steganography ======
 Steganography is the art and science of writing hidden messages.
@@ Line 10: / Line 20: @@
 We will dive into digital steganography.
-The folowing sections will present some techniques of digital steganography.
+The following sections will present some techniques of digital steganography.
 ===== Simple steganography art =====
-In computer scinece a well known method of hiding data (message) is to concatenate these data to an archive.
+In computer science a well known method of hiding data (message) is to concatenate these data to an archive.
 For example, if I want to hide a text file in a music file:
@@ Line 135: / Line 145: @@
 ===== Steganalysis of the LSB method with sets =====
-We will hide a message in a picture with the simple LSB method and with the LSP method + sets.
+You must [[security:steganography#installation_of_stegano|install Stéganô]] before running these commands.
+First, we will hide a message in a picture with the simple LSB method and with the LSB method + sets.
 <code bash>
-$ python ./slsb-gen.py --hide -i ../examples/pictures/Montenach.png -o ./Montenach-enc-gen.png --generator eratosthenes -f ../examples/lorem_ipsum.txt
+$ cd stegano
-$ python ./slsb.py --hide -i ../examples/pictures/Montenach.png -o ./Montenach-enc.png  -f ../examples/lorem_ipsum.txt
+# LSB with The Eratosthenes set
+$ slsb-set --hide -i ./examples/pictures/Montenach.png -o ~/Montenach-enc-gen.png --generator eratosthenes -f ./examples/lorem_ipsum.txt
+# LSB only
+$ slsb --hide -i ./examples/pictures/Montenach.png -o ~/Montenach-enc.png  -f ../examples/lorem_ipsum.txt
 </code>
+The selected generator //Sieve of Eratosthenes// (''--generator eratosthenes'') will generate the set of points. This set of points will be used in order to select the pixels where the informations will be hidden.
+The following will generate the corresponding steganalysed pictures (left column):
 <code bash>
-$ python steganalysis-parity.py -i ./Montenach-enc.png -o ./Montenach-enc-steg.png
+# Steganalysis of the original image
-$ python steganalysis-parity.py -i ./Montenach-enc-gen.png -o ./Montenach-enc-gen-steg.png
+$ steganalysis-parity -i ../examples/pictures/Montenach.png -o ~/Montenach-steg.png
-$ python steganalysis-parity.py -i ../examples/pictures/Montenach.png -o ./Montenach-steg.png
+# Steganalysis of the image with hidden text (LSB only)
+$ steganalysis-parity -i ~/Montenach-enc.png -o ~/Montenach-enc-steg.png
+# Steganalysis of the image with hidden text (LSB + Eratosthenes)
+$ steganalysis-parity -i ~/Montenach-enc-gen.png -o ~/Montenach-enc-gen-steg.png
 </code>
+{{:security:montenach.png?700*500|Original image}}
+{{ :security:montenach-steg.png?700*500|(1) Steganalysis of the original image}}
+{{:security:montenach-enc.png?700*500|Image with hidden text  (LSB only)}}
+{{ :security:Montenach-enc-steg.png?700*500|(2) Steganalysis of the image with hidden text (LSB only)}}
 {{:security:montenach-enc-gen.png?700*500|Image with hidden text  (LSB + Eratosthenes)}}
-{{ :security:montenach-enc-gen-steg.png?700*500|Steganalysis of the image with hidden text (LSB + Eratosthenes)}}
+{{ :security:montenach-enc-gen-steg.png?700*500|(3) Steganalysis of the image with hidden text (LSB + Eratosthenes)}}
+Compare the pictures 1 and  2 and compare the pictures 1 and 3, left column.
+==== Reveal the message ====
+<code bash>
+$ slsb-set --reveal --generator eratosthenes -i ~/Montenach-enc-gen.png -b ~/file-gen.txt
+$ slsb --reveal  -i ~/Montenach-enc.png -b ~/file.txt
+$ cmp ~/file-gen.txt ~/file.txt
+$ cat ~/file.txt
+Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nam placerat fermentum
+lorem, at porttitor metus congue eu. Mauris vitae tell
+.
+.
+.
+$ slsb-set --reveal --generator fermat -i ~/Montenach-enc-gen.png -b ~/file.txt
+Impossible to detect message.
+$ slsb-set --reveal --generator mersenne -i ~/Montenach-enc-gen.png -b ~/file.txt
+Impossible to detect message.
+</code>