(IJCSIS) International Journal of Computer Science and Information Security, Vol. 11, No. 11, 2013 On the Information Hiding Technique Using Least Significant Bits Steganography Samir El-Seoud Faculty of Informatics and Computer Science, The British University in Egypt, Cairo, Egypt Islam Taj-Eddin Faculty of Informatics and Computer Science, The British University in Egypt, Cairo, Egypt Abstract—Steganography is the art and science of hiding data or the practice of concealing a message, image, or file within another message, image, or file. Steganography is often combined with cryptography so that even if the message is discovered it cannot be read. It is mainly used to maintain private data and/or secure confidential data from misused through unauthorized person. In contemporary terms, Steganography has evolved into a digital strategy of hiding a file in some form of multimedia, such as an image, an audio file or even a video file. This paper presents a simple Steganography method for encoding extra information in an image by making small modifications to its pixels. The proposed method focuses on one particular popular technique, Least Significant Bit (LSB) Embedding. The paper uses the (LSB) to embed a message into an image with 24-bit (i.e. 3 bytes) color pixels. The paper uses the (LSB) of every pixel’s bytes. The paper show that using three bits from every pixel is robust and the amount of change in the image will be minimal and indiscernible to the human eye. For more protection to the message bits a Stego-Key has been used to permute the message bits before embedding it. A software tool that employ steganography to hide data inside of other files (encoding) as well as software to detect such hidden files (decoding) has been developed and presented. Key Words—Steganography, Hidden-Data, Embedding-Stego- Medium, Cover-Medium, Data, Stego-Key, Stego-Image, Least Significant Bit (LSB), 24-bit color pixel, Histogram Error (HE), Peak Signal Noise Ratio (PSNR), Mean Square Error (MSE). I. INTRODUCTION One of the most important properties of digital information is its easiness in producing and distributing unlimited number of its copies (i.e. copies of text, audio and video data) regardless of the protection of the intellectual and production rights. That requires innovative ways of embedding copyright information and serial numbers in those copies. Nowadays, the need for private and personal computer communication for sharing confidential information between two parties has increased. One such technique to solve the above mentioned problems is Steganography [11][3]. It is the art of hiding private information in public information used or sent on public domain or communication from an unwanted party. These private information need to be undetectable and/or irremovable, especially for the audio and video data cases. The art of hiding messages is an ancient one. Steganography (literally meaning covered writing) is a form of security through obscurity. For example, a message might be hidden within an image. One method to achieve that is by changing the least significant bits to be the message bits. The term steganography was introduced at the 15th century. Historically, steganography was used for long time ago. Messages were hidden (i.e. tattooed) on the scalp of slaves. One famous example being Herodotus who in his histories tells how Histiaeus shaved the head of his most trusted slave and tattooed it with a message which disappeared once the hair grew back again. Invisible ink has been for quite some time. Microdots and microfilm technology used after the advance of the photography science and technology. Steganography hides the private message but not the fact that two parties are communicating. The process involves placing a hidden message in a transport medium (i.e. the carrier). The secret message is embedded in the carrier to form the steganography medium. Steganography is generally implemented by replacing bits of data, in regular computer files, with bits of different, invisible information. Those computer files could be graphics, sound, text or HTML. The hidden information can be plain text, cipher text, or images. In paper [2], the authors suggested an embedding algorithm, using two least significant bits that minimize the difference between the old value of the pixel in the cover and the new value of the pixel in the stego-image in order to minimize the distortion made to the cover file. Experimental results of the modified method show that PSNR is greater than the conventional method of LSBs replacement. A distinguish between stegnography and cryptography should be emphasized. Steganography is the science and art of hiding information from a third party. Cryptography is the science and art of making data unreadable by a third party. Cryptography got more attention from both academia and industry than steganography. 34 http://sites.google.com/site/ijcsis/ ISSN 1947-5500
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(IJCSIS) International Journal of Computer Science and Information Security, Vol. 11, No. 11, 2013
On the Information Hiding Technique Using Least
Significant Bits Steganography
Samir El-Seoud
Faculty of Informatics and Computer Science,
The British University in Egypt,
Cairo, Egypt
Islam Taj-Eddin
Faculty of Informatics and Computer Science,
The British University in Egypt,
Cairo, Egypt
Abstract—Steganography is the art and science of hiding data or
the practice of concealing a message, image, or file within another
message, image, or file. Steganography is often combined with
cryptography so that even if the message is discovered it cannot
be read. It is mainly used to maintain private data and/or secure
confidential data from misused through unauthorized person. In
contemporary terms, Steganography has evolved into a digital
strategy of hiding a file in some form of multimedia, such as an
image, an audio file or even a video file. This paper presents a
simple Steganography method for encoding extra information in
an image by making small modifications to its pixels. The
proposed method focuses on one particular popular technique,
Least Significant Bit (LSB) Embedding. The paper uses the
(LSB) to embed a message into an image with 24-bit (i.e. 3 bytes)
color pixels. The paper uses the (LSB) of every pixel’s bytes. The
paper show that using three bits from every pixel is robust and
the amount of change in the image will be minimal and
indiscernible to the human eye. For more protection to the
message bits a Stego-Key has been used to permute the message
bits before embedding it. A software tool that employ
steganography to hide data inside of other files (encoding) as well
as software to detect such hidden files (decoding) has been
A proposed Pseudo-code for extracting hidden messages:
VI. EXPERIMENTS
This Section explains the steganography application in order
to encode a text message into image file and decode that
message from the stegano file.
The following figure shows the Main Menu screen with three
buttons: the two buttons in the upper side of the screen used for
encrypting and decrypting a text message into image file, the
third button in the middle of lower side of the screen is used for
encrypting and decrypting images.
By pressing the Encrypt Text File text box button or Dealing
With Images text box button will lead you to the first screen
of the encoding process, after you finish the encoding process
click the button in the upper right side of the screen Decrypt
The Stegano File to continue the decoding process.
A. Encoding: 1) Step 1
In the first step, insert the path of the required image to be
encoded in the “Source Image File” text box, or click the
Browse button to select it. The selected image could be seen
in the “Source Image Preview” picture box (see figure 7).
The application shows the image size in bytes in the
“Image Size” text box, and it also shows how many bytes you
can hide inside this image. The maximum number of bytes you could hide will be displayed in the text box "You can hide up to" (see figure 7). Click button Next to proceed to the next
(IJCSIS) International Journal of Computer Science and Information Security, Vol. 11, No. 11, 2013
2) Step 2 In the next step two options are available (see fig. 8):
a) Either write the required text message to be hide in
the image in the text box shown on the screen.
b) Or select the file that contains the text message to be
hide in the image by clicking the button Browse
and insert the path in the text box "File Name".
The number of bytes to be encoded in the image will be displayed in the text box "No. of Bytes". Click button "Next"
to proceed to the next step.
3) Step 3 In the third step (see fig. 9) type the output image name
that contains the encoded message in the text box "Stego File Name", and a security password in the text box "Password".
Finally, click button "Finish" to create the target file and
go to the next step.
Here below is the encoded message (text) into the source
image
4) Step 4 At this screen (see fig. 10), a comparison between the
original image before encoding (Cover Image) and the output
image after encoding (Stego Image) could be seen by the
naked eye.
Click button "Close" when finishing comparison.
If the button "Decrypt The Stegano File" at the Main
Menu screen (Figure 6) had been pressed, then the next screen
will leads the user through two steps to complete the decoding
stage. These two steps are explained below:
B. Decoding: 1) Step1
At this stage, the encoded message with the given stegofile
name is stored in main directory with the current path.
Now go to the main menu (see fig. 6) and click, this time, the
button “Decrypt”. Click button "Browse" to select the new
created image (encoded image) and the application will show the encoded image size in bytes in the text box "Stego Image Size". Also the encoded image will be shown in the