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Data Hiding using LSB Steganography technique Rituraj Rusia 1 , Munendra Kumar Mishra 2 , R. K. Tiwari 3 1 Ph.D.(CS) Research Scholar, MGCGVV, Chitrakoot (MP) 2 Vindhya Institute of Technology and Science (VITS), Satna (MP) 3 Head of Dept. of Physics, Govt. M. S. Golvarkar New Science College, Rewa (MP) 1 riturajrusia@gmail.com 2 munendra.mca@gmail.com 3 rkt084@gmail.com Abstract The applications accessing multimedia systems and content over the Web have grown extremely in the past few years. Furthermore, many end users can easily use tools to synthesize and edit multimedia information. Thus, security has become one of the most significant problems for distributing new information technology. It is necessary to protect this information while communicated over insecure channels. It is also important to determine where and how such a multimedia file is confidential. Thus, a need exists for developing technology that will help protect the integrity of digital content and secure the intellectual property rights of owners. Cryptography is a means to achieve this task. In this paper, a secured package is implemented and integrated under the hash function umbrella to provide appropriate services for protecting multimedia through communication channels. The algorithm was tested with different cryptosystems using multimedia files under windows environment and it was proved that extracting any information about the encrypted information is hard for any eavesdropper with computational resources. In addition, information security results with experimental examples are discussed and finally conclusion and remarks are presented. KEYWORDS Cryptography, Steganography, Stego-image, Data Hiding, Encryption, Decryption, Multimedia Information, Image Compression, Embedding, etc. 1. Introduction While in multimedia communications, the need of confidentiality and privacy gains more and more in importance, particularly in open networks like the Internet. In this age of universal electronic connectivity, of viruses and hackers, of electronic eavesdropping and electronic fraud, there is indeed a need to protect information from passing before curious eyes or, more importantly, from falling into wrong hands. Thus, multimedia security is much to consider in distributing digital information safety. Cryptography is the study of mathematical techniques related to aspects of information security such as confidentiality, data integrity, entity authentication, and data origin authentication [1-3]. Cryptography scrambles a message so it cannot be understood. Steganography hides the message so it cannot be seen. A message in ciphertext, for instance, might arouse suspicion on the part of the recipient while an “invisible” message created with steganographic methods will not. Cryptography is probably finding its widest use today (and perhaps its widest use in history) in securing and validating information in many applications. Secure sockets layer (SSL) and transport layer security (TLS), used to encrypt information exchanges conducted over the World Wide Web. In the next section, a brief of how this package is working and its stages are presented. 1.1. The State of the Art: This package works in a sequence (sometimes these stags are optional). The two parties who are in communication, usually called Alice, the Sender, and Bob, the receiver will start to communicate. The sender decides if the plaintext needs to be compressed or not depending on its size. Then the key, which will be used in the encryption process, will be hashed using a hash technique and inserted into the plaintext as a message authentication code (MAC). This plaintext is encrypted using a cryptosystem that is called Key-Based Security Algorithm (KBSA) [4]. The compressed hashed encrypted data is then embedded into an innocent image “cover-image” after preprocessing it using a steganographic algorithm producing stego-image. Before this stego-image is transmitted through communication channels to the other party, it is compressed using image compression. This communication takes place in the presence of a warden. The receiver by his role will do the reverse operation to extract the original plaintext after extracting it from the stego- image. The relative entropy between the cover image and the stego image is zero. A tractable objective measure for this property is the (weighted) mean squared error between the cover image and the stego image (embedding distortion). The resulting stego and the cover images should be indistinguishable by the naked eye. In the next sections a description is given of the package stages including cryptographic algorithms, network security, hash Rituraj Rusia et al, Int.J.Computer Technology & Applications,Vol 5 (4),1495-1505 IJCTA | July-August 2014 Available online@www.ijcta.com 1495 ISSN:2229-6093
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  • Data Hiding using LSB Steganography technique

    Rituraj Rusia1, Munendra Kumar Mishra2, R. K. Tiwari3 1Ph.D.(CS) Research Scholar, MGCGVV, Chitrakoot (MP)

    2 Vindhya Institute of Technology and Science (VITS), Satna (MP) 3Head of Dept. of Physics, Govt. M. S. Golvarkar New Science College, Rewa (MP)

    1 riturajrusia@gmail.com 2 munendra.mca@gmail.com

    3 rkt084@gmail.com

    Abstract

    The applications accessing multimedia systems and

    content over the Web have grown extremely in the

    past few years. Furthermore, many end users can

    easily use tools to synthesize and edit multimedia

    information. Thus, security has become one of the

    most significant problems for distributing new

    information technology. It is necessary to protect

    this information while communicated over insecure

    channels. It is also important to determine where

    and how such a multimedia file is confidential.

    Thus, a need exists for developing technology that

    will help protect the integrity of digital content and secure the intellectual property rights of owners.

    Cryptography is a means to achieve this task.

    In this paper, a secured package is implemented

    and integrated under the hash function umbrella to

    provide appropriate services for protecting

    multimedia through communication channels. The

    algorithm was tested with different cryptosystems

    using multimedia files under windows environment

    and it was proved that extracting any information

    about the encrypted information is hard for any

    eavesdropper with computational resources. In

    addition, information security results with

    experimental examples are discussed and finally

    conclusion and remarks are presented.

    KEYWORDS Cryptography, Steganography, Stego-image,

    Data Hiding, Encryption, Decryption, Multimedia Information, Image Compression, Embedding, etc.

    1. Introduction While in multimedia communications, the need

    of confidentiality and privacy gains more and more

    in importance, particularly in open networks like

    the Internet. In this age of universal electronic

    connectivity, of viruses and hackers, of electronic

    eavesdropping and electronic fraud, there is indeed

    a need to protect information from passing before curious eyes or, more importantly, from falling into

    wrong hands. Thus, multimedia security is much to

    consider in distributing digital information safety.

    Cryptography is the study of mathematical

    techniques related to aspects of information

    security such as confidentiality, data integrity,

    entity authentication, and data origin authentication

    [1-3]. Cryptography scrambles a message so it

    cannot be understood. Steganography hides the

    message so it cannot be seen. A message in

    ciphertext, for instance, might arouse suspicion on

    the part of the recipient while an invisible

    message created with steganographic methods will

    not. Cryptography is probably finding its widest

    use today (and perhaps its widest use in history) in

    securing and validating information in many

    applications. Secure sockets layer (SSL) and

    transport layer security (TLS), used to encrypt

    information exchanges conducted over the World

    Wide Web. In the next section, a brief of how this

    package is working and its stages are presented.

    1.1. The State of the Art: This package works in a sequence (sometimes

    these stags are optional). The two parties who are

    in communication, usually called Alice, the Sender,

    and Bob, the receiver will start to communicate.

    The sender decides if the plaintext needs to be

    compressed or not depending on its size. Then the

    key, which will be used in the encryption process,

    will be hashed using a hash technique and inserted

    into the plaintext as a message authentication code

    (MAC). This plaintext is encrypted using a

    cryptosystem that is called Key-Based Security

    Algorithm (KBSA) [4]. The compressed hashed

    encrypted data is then embedded into an innocent

    image cover-image after preprocessing it using a

    steganographic algorithm producing stego-image.

    Before this stego-image is transmitted through

    communication channels to the other party, it is compressed using image compression. This

    communication takes place in the presence of a

    warden. The receiver by his role will do the

    reverse operation to extract the original plaintext

    after extracting it from the stego- image. The

    relative entropy between the cover image and the

    stego image is zero. A tractable objective measure

    for this property is the (weighted) mean squared

    error between the cover image and the stego image

    (embedding distortion). The resulting stego and the

    cover images should be indistinguishable by the

    naked eye. In the next sections a description is

    given of the package stages including

    cryptographic algorithms, network security, hash

    Rituraj Rusia et al, Int.J.Computer Technology & Applications,Vol 5 (4),1495-1505

    IJCTA | July-August 2014 Available online@www.ijcta.com

    1495

    ISSN:2229-6093

    mailto:riturajrusia@gmail.commailto:munendra.mca@gmail.commailto:rkt084@gmail.com

  • function, steganographic algorithms, and

    compression algorithm that are used to accomplish

    the model. In this package more than 12

    cryptosystems were implemented, 3 hash function

    algorithms and 1 steganographic algorithm

    gathered together into a library that might work

    easily and is manipulated by the user to deal with

    the multimedia plaintext.

    1.2. Basic Concepts and Related Work: There are many aspects to security and many

    applications. One essential aspect for secure

    communications is that of cryptography. But it is

    important to note that while cryptography is

    necessary for secure communications, it is not by

    itself sufficient. There are some specific security

    requirements for cryptography, including

    Authentication, Privacy /confidentiality, and

    Integrity Non -repudiation. The three types of

    algorithms are described:[18]

    (i) Secret Key Cryptography (SKC): Uses a

    single key for both encryption and decryption.

    (ii) Public Key Cryptography (PKC): Uses one

    key for encryption and another for decryption.

    (iii) Hash Functions: Uses mathematical

    transformation to irreversibly "encrypt"

    information. Steganography is the other technique for secured

    communication. It encompasses methods of

    transmitting a secret message through innocuous

    cover carriers in such a manner that the very

    existence of the embedded messages is

    undetectable. Information can be hidden in images,

    audio, video, text, or some other digitally

    representative code.

    Steganography systems can be grouped by the

    type of covers used (graphics, sound, text,

    executable) or by the techniques used to modify the

    covers

    a) Substitution system.

    b) Transform domain techniques.

    c) Spread spectrum techniques.

    d) Statistical method.

    e) Distortion techniques. f) Cover generation methods.

    Text steganography, Image steganography,

    Audio steganography, video steganography, and

    Protocol steganography. Some of the

    steganography methods are

    1. LSB

    2. MASKING

    3. FILTERING

    4. TRANSFORM TECHNIQUE

    The best known steganographic method that

    works in the spatial domain is the LSB (Least

    Significant Bit), which replaces the least significant

    bits of pixels selected to hide the information. A

    large number of commercial steganographic

    programs use the Least Significant Bit embedding

    (LSB) as the method of choice for message hiding

    in 24-bit, 8-bit color images, and grayscale images

    [6]. In this paper we have used LSB algorithm for

    steganography..

    2. Cryptographic Algorithms The most complete non-technical account of the

    subject is Kahn's the Codebreakers [1-3].

    Completed in 1963, Kahn's book covers those

    aspects of the history, which were most significant

    (up to that time) to the development of the subject.

    A cryptographic algorithm transforms

    cryptographic key and readable (plaintext) data into

    ciphertext that can only be understood by applying

    another (possibly the same) cryptographic key and

    crypto-algorithm to it [6-9]. If the keys and

    algorithms are the same, we have a symmetric or

    secret-key crypto system like the DES, IDEA, etc.

    If the algorithm involves two different keys, one

    for enciphering and the other for deciphering, we have an asymmetric or public-key algorithm like

    the RSA, EL-Gamal, etc. Data protected with

    encryption may be transmitted over communication

    channels (e.g., a satellite link, telephone lines,

    network, etc) before it arrives at its final

    destination. For example, data may be input from a

    users terminal to the users program, where it is

    processed and then transmitted to a disk file for

    storage. Later, the user may retrieve the data and

    have it displayed on the terminal. In computer

    networks, data may be transmitted from one

    location on the network to another for processing or

    for any location (computer, terminal, front-end, or

    program) where data may be input, stored,

    encrypted, processed, routed (switched), or output;

    and link for any communication line or data bus

    between two nodes. That it is what will be discussed in the next subsection.

    2.1. Simplified DES (S-DES): The S-DES encryption algorithm takes an 8-bit

    block of plaintext (example: 10111101) and a 10-

    bit key as input and produces an 8-bit block of

    ciphertext as output. The S-DES decryption

    algorithm takes an 8-bit block of ciphertext and the

    same 10-bit key used to produce that ciphertext as

    input and produces the original 8-bit block of

    plaintext. The encryption algorithm involves five

    functions: an initial permutation (IP); a complex

    function labeled fK, which involves both

    permutation and substitution operations and

    depends on a key input; a simple permutation

    function that switches (SW) the two halves of the

    data; the function fK again; and finally a permutation function that is the inverse of the

    initial permutation (IP1). The function fK takes

    two 8-bit keys which are obtained from the original

    10-bit key [15]. The S- DES algorithm flow is

    shown in below figure.

    The 10-bit key is first subjected to a permutation

    (P10) and then a shift operation is performed. The

    Rituraj Rusia et al, Int.J.Computer Technology & Applications,Vol 5 (4),1495-1505

    IJCTA | July-August 2014 Available online@www.ijcta.com

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    ISSN:2229-6093

  • output of the shift operation then passes through a

    permutation function that produces a 8- bit output

    (P8) for the first sub key (K1). The output of the

    shift operation again feeds into another shift and

    (P8) to produce the 2nd sub key (K2) [17].We can

    express encryption algorithm as superposition

    Considering a 24-bpp color image, the image is

    split into three matrices (frames) each matrix

    containing pixels indicating the intensities of Red, Green and Blue. If m by n is the dimension of that

    image, then there will be (m x n) number of pixels

    in that image. Hence, the matrices corresponding to

    Red, Green and Blue intensities will also have (m x

    n) number of pixels.

    2.2. Proposed Technique:

    (a) Proposed Message Embedding Procedure:

    Figure-1: Sender Prospect

    Figure-1 shows the senders prospect of

    Proposed Technique in which the secret

    information is encrypted by using simplified data

    encrypted standard (S- DES) encryption algorithm.

    Then encrypted message is embedded into cover

    image by using Alteration component technique. Image containing the secret data is called stego

    image. Next phase is to select the stego key for

    encoding. In Embedding process data is hidden by

    using Alteration component technique in which

    pixels have been replaced by key and secret

    message. Firstly key is converted into binary form

    and its binary form is filled in the first component

    of first pixels. After then, secret message is

    converted into binary form and its binary form is

    filled in first component of next pixels.

    Embedding Algorithm: Step (a): Extract all the pixels in the given

    image and store it in the array called Pixel- Array.

    Step (b): Extract all the characters in the given

    text file and store it in the array called Character-

    Array.

    Step (c): Extract all the characters from the Stego key and store it in the array called Key-

    Array.

    Step (d): Choose first pixel and pick characters

    from Key- Array and place it in first component of

    pixel. If there are more characters in Key- Array,

    then place rest in the first component of next pixels,

    otherwise follow Step (e).

    Step (e): Place some terminating symbol to

    indicate end of the key. 0 has been used as a

    terminating symbol in this algorithm.

    Step (f): Place characters of Character- Array in

    each first component (blue channel) of next pixels

    by replacing it.

    Step (g): Repeat step (f) till all the characters has been embedded.

    Step (h): Again place some terminating symbol

    to indicate end of data.

    Step (i): Obtained image will hide all the

    characters that we input.

    (b) Proposed Message Extraction Procedure:

    Figure-2: Receiver Prospect

    Figure-2 shows the receivers prospect of Proposed Technique in which the sender sends a

    stego-image to the receiver or legitimate user. The

    legitimate user having the stego key to extract

    secret data from stego image. The legitimate user

    must have the same key with which the image is

    embedded. On Stego image Extracting process is

    applied by using Alteration component technique.

    After data extraction I get the secret message which

    is in encrypted form. Simplified data encryption

    standard (S-DES) decryption algorithm is used to

    decrypt message. Finally we get the Secret Data

    which is embedded.

    Extraction Algorithm: Step (a): Consider three arrays. Let they be

    Character-Array, Key-Array and Pixel- Array.

    Step (b): Extract all the pixels in the given

    image and store it in the array called Pixel- Array. Step (c): Now, start scanning pixels from first

    pixel and extract key characters from first (blue)

    component of the pixels and place it in Key-Array.

    Follow Step 3 till we get terminating symbol,

    otherwise follow step (d).

    Step (d): If this extracted key matches with the

    key entered by the receiver, then follow Step 5,

    otherwise terminate the program by displaying

    message Key is not matching.

    Step (e): If the key is valid, then again start

    scanning next pixels and extract secret message

    characters from first (blue) component of next

    Rituraj Rusia et al, Int.J.Computer Technology & Applications,Vol 5 (4),1495-1505

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  • pixels and place it in Character Array. Follow Step

    (e) till we get terminating symbol, otherwise follow

    step (f).

    Step (f): Extract secret message from Character-

    Array.

    2.3. Analysis of the Network Security: A model for network security, in general terms,

    is shown in Figure-3. A message is to be

    transferred from one party to another across some sort of networks as in the Internet [2]. The two

    parties, who are the principals in this transaction,

    must cooperate for the exchange to take place. A

    logical transformation channel is established by

    defining a route through the internet from source to

    destination and by the cooperative use of

    communication protocols (e.g., TCP/IP) by the two

    principals.

    Figure-3: A model for network security.

    Data is encrypted on a network using

    either link or end-to-end encryption. In general,

    link encryption is performed by service providers,

    such as a data communications provider. Link

    encryption encrypts all of the data along a

    communications path. Since link encryption also

    encrypts routing data, communications nodes need

    to decrypt the data to continue routing. End-to-end encryption is generally performed by the end user

    organization. Although data remains encrypted

    when being passed through a network, routing

    information remains visible. It is possible to

    combine both types [3]. In the next subsection, the

    hash function is introduced.

    2.4. Hash Function and Data Integrity: Cryptography hashing functions play a

    fundamental role in modern cryptography [4].

    Hash functions take a message as input and

    produce an output referred to as a hashcode, hash-

    result, hash-value, or simply hash. In our model the

    hashcode works with the key used in the encryption

    procedure like the SHA1, Rip-MD 160, etc. More

    precisely, a hash function maps bitstrings of

    arbitrary finite length to strings of fixed length as

    shown in Figure-4.

    Figure-4: General Structure of Secure Hash

    Code. The basic idea of cryptographic hash functions

    is that a hash-value serves as a compact

    representative image (sometimes called an imprint,

    digital fingerprint, or message digest) of an input

    string, and can be used as if it were uniquely

    identifiable with that string. Hash functions are

    used for data integrity as a message authentication

    code (MAC), allows message authentication by

    symmetric techniques. The next subsection

    presents steganography algorithms.

    2.5. Architecture:

    Steganography is a science, which dates back to

    ancient times. It has been used by ordinary people,

    spies, rulers, governments, armies, etc down

    through the ages. It is the original method of

    information concealment. Information has been

    hidden in drawings, paintings, books, newspapers, in speech, in written word, even in postage stamps

    [10].

    The Greeks, from the histories of Herodotus,

    wrote text on wax-covered tablets. In one story,

    Demeratus wanted to notify Sparta that Xerxes

    intended to invade Greece. To avoid capture, he

    scraped the wax off the tablets and wrote a message

    on the underlying wood. He then covered the

    tablets with wax again. The tablets appeared to be

    blank and unused so they passed inspection by

    sentries without question.

    The Egyptians, used illustrations to conceal

    messages. The idea being that one party could send

    the illustration to the other in reasonable

    confidence that if the messenger was questioned

    then the illustration would not arouse any interest

    from his enemies.

    The Chinese, would often write on thin silk or paper, which they rolled into a ball and covered in

    wax. A messenger hid the ball somewhere on his

    person, sometimes by swallowing it. This is a form

    of steganography.

    Steganography is the art of communicating

    messages by embedding them into multimedia data

    (usually digital images). It is desired to maximize

    the amount of hidden information (embedding rate)

    while preserving security against detection by

    unauthorized parties. Steganography system Like

    the Least Significant Bit LSB should fulfill the

    same requirements posed by the "Kerckhoff

    principle" in cryptography [11].

    Architecture consists of four basic blocks

    a) Encryption: Matrix Mapping Method for

    Symmetric Key Cryptography

    Rituraj Rusia et al, Int.J.Computer Technology & Applications,Vol 5 (4),1495-1505

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  • b) Steganography: Modified BPCS

    c) Decryption Matrix Mapping Method for

    Symmetric Key Cryptography

    d) Desteganography: Modified BPCS

    Figure-5: Architecture Diagram of System

    a) Encryption: Matrix Mapping Method for Symmetric Key

    Cryptography In this algorithm, using the key we

    generate a mapping matrix. Every bytes of the mapping image is unique and is with respect to key.

    The mapping matrix is of size 16 by 16.This

    algorithm is influenced by Applied cryptography in

    Java (Partida, A.Andina, D.Atos).

    Algorithm:

    1) The source file is opened for reading in

    binary mode.

    2) Every bytes of the source file is read and

    converted into its equivalent 8-bit binary number.

    3) Split the 8-bit binary number into 4-bit higher

    and lower nibble number.

    4) Convert these two 4-bit nibbles into its

    equivalent decimal value.

    5) With the help of these two decimal values

    pick up a pixel from the mapping matrix. Where

    higher nibble equivalent decimal value acts as row

    indicator and lower nibble equivalent decimal value acts as column indicator for mapping image.

    6) Replace the original pixel with the byte

    selected from mapping matrix.

    7) Encrypted file gets generated as the above

    process is repeated for all the pixels.

    b) Steganography: Modified BPCS: Our new Steganography uses an image as the

    vessel data, and we embed secret information in the

    bit- planes of the vessel. This technique makes use

    of the characteristics of the human vision system

    whereby a human cannot perceive any shape

    information in a very complicated binary pattern.

    We can replace all of the noise-like regions in the

    bit-planes of the vessel image with secret data

    without deteriorating the image quality. This

    algorithm is influenced by Principle and application

    of BPCS-Steganography (Eiji Kawaguchi and Richard O.Eason).This algorithm is termed as

    Modified BPCS-Steganography, which stands for

    Bit-Plane Complexity Segmentation

    Steganography. Input data will be vessel image and

    data to embed in byte format. Load the vessel

    image into memory. Get width and height of the

    memory image. Generate a threshold value. For

    each pixel get red, green and blue values of current

    pixel.

    Algorithm: Real Image and data to Embed in byte array

    format is given as input.

    1) Load the vessel image into memory. 2) Get a "readable pen" for the memory image.

    3) Get width and height of the memory image.

    4) Generate a threshold value.

    5) Loop for all rows of memory image

    Loop for all cols of memory image

    a) Using the "readable pen" get red, green

    and blue values of current pixel.

    b) If red

  • Figure-6: Algorithm to encrypt data and embed it

    into image

    c) Decryption: Matrix Mapping Method for Symmetric Key Cryptography:

    In this algorithm, using the key we generate a

    mapping matrix. Every bytes of the mapping image

    is unique and is with respect to key. The mapping

    matrix is of size 16 by 16.

    Algorithm: 1) The encrypted file is opened for reading in

    binary mode.

    2) Every bytes of the encrypted file is read and

    converted into its equivalent 8-bit binary number.

    3) Match the byte in the mapping matrix and

    find out row and column number of the matched

    byte.

    4) Form 2 nibbles using the row number and

    column number. Generate 8-bit binary number

    from 4-bit higher (row) and lower (column) nibble

    number.

    5) Substitute this generated 8 bit binary data in

    place of the current byte.

    6) Original file gets generated as the above

    process is repeated for all the pixels.

    Get the bytes from image using Desteganography and use the key to generate

    decryption matrix. Now match the byte which we

    got from image with each matrix element. And get

    corresponding row and column number of matched

    element. Convert the obtained row and column

    number into binary format. Deconjugate these two

    numbers which represents original data.

    d) Desteganography: Modified BPCS:

    Figure-7: Algorithm to decrypt data and extract

    from image

    Image having embedded data is given as input.

    Algorithm:

    1) Load the image into memory.

    2) Get a "readable pen" for the memory image.

    3) Get width and height of the memory image.

    4) Generate a threshold value.

    5) Loop for all rows of memory image

    Loop for all cols of memory image

    a) Using the "readable pen" get red, green

    and blue values of current pixel.

    b) If red

  • data. Digital images are typically stored in either

    24-bit or 8-bit files. A 24-bit image provides the

    most space for hiding information; however, it can

    be quite large (with the exception of JPEG images).

    All color variations for the pixels are derived from

    three primary colors: red, green, and blue. Each

    primary color is represented by 1 byte; 24-bit

    images use 3 bytes per pixel to represent a color

    value. These 3 bytes can be represented as hexadecimal, decimal, and binary values. In many

    Web pages, the background color is represented by

    a six-digit hexadecimal number- actually three

    pairs representing red, green, and blue. A white

    background would have the value FFFFFF: 100

    percent red (FF), 100 percent green (FF), and 100

    percent blue (FF). Its decimal value is 255, 255,

    255, and its binary value is 11111111, 11111111,

    11111111, which are the three bytes making up

    white. This definition of a white background is

    analogous to the color definition of a single pixel in

    an image. Pixel representation contributes to file

    size. For example, suppose a 24-bit image 1024 x

    768 - a common resolution for high-resolution

    graphics. Such an image has more than 2 million

    pixels, each having such a definition, which would

    produce a file exceeding 2 Mbytes. Such a huge size for the cover image is considered as an

    advantage for embedding larger messages. On the

    other hand, such 24-bit images are still relatively

    uncommon on the Internet, their size would attract

    attention during transmission. Thus, using image

    compression for the cover image can solve such

    contradiction and would be beneficial, if not

    necessary, to transmit such a file. How to embed

    the data will be available in the next subsection.

    1.1. Embedding Data: Embedding data, which is to be hidden,

    into an image requires two files. The first is the

    innocent-looking image that will hold the hidden

    information, called the cover image. The second

    file is the message - the information to be hidden.

    A message may be plain text, ciphertext, other images, or anything that can be embedded in a bit

    stream. When combined, the cover image and the

    embedded message make a stego image. A stego-

    key (a type of password) may also be used to hide,

    and then later decode, the message [12]. In 8-bit

    color images such as GIF files, each pixel is

    represented as a single byte, and each pixel merely

    points to a color index table (a palette) with 256

    possible colors. The pixels value, then, is between

    0 and 255. The software simply paints the

    indicated color on the screen at the selected pixel

    position. When considering an image in which to

    hide information, one must consider the image as

    well as the palette. Obviously, an image with large

    areas of solid colors is a poor choice, as variances

    created from the embedded message will be

    noticeable in the solid areas. Once selecting a

    cover image, one must decide on a technique to

    hide the information wanted to embed.

    1.2. Digital Image Preprocessing: In the embedding module, all of the gray

    scales of the pixels within a block will be modified

    such that the mean intensity value of the block will

    be equal to the closest center of an interval. If there

    are too many pixels whose gray scales are near the gray scale boundary, i.e., 0 or 255, it will be hard to

    adjust the mean intensity value while maintaining

    the image fidelity. For example, the mean value of

    a block is 195, and half of pixels in this block have

    gray scale 255, and the desired interval center is

    210. Since half of pixels could not be adjusted,

    other pixels will be added 30 on the average. This

    change may be too large to maintain the image

    fidelity. Thus, a preprocessing is provided to make

    all gray scales away from the boundary [12, 13].

    Many steganography experts recommend using

    images featuring 256 shades of gray. Gray-scale

    images are preferred because the shades change

    very gradually from byte to byte, and the less the

    value changes between palette entries, the better

    they can hide information. Figure-8 shows a gray-

    scale palette of 256 shades.

    Figure-8: Gray-scale palette of 256 shades.

    1.3. The Proposed Kbsa Steganographic: In this section, a block diagram of the package

    model KBSA [4] stages for multimedia

    communications is presented as shown in Figure-9.

    Many experiments were done in the lab using

    image files and text message. Only a sample is

    presented and it is shown that the stego image

    cannot indicate that it contains any information so,

    no one might suspect in that innocent image and the extracted message is same like the original

    message.

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  • Figure-9: The block diagram of a general KBSA

    package model using compressed, hashed,

    encrypted and steganographic algorithms.

    More recently, people are hiding secret

    messages in graphic images. Replace the least

    significant bit of each byte of the image with the

    bits of the message. The graphical image will not

    change appreciably - most graphics standards

    specify more gradations of color than the human

    eye can notice - and the message can be stripped

    out at the receiving end. One can store a 64-kilobyte message in a 1024 1024 grey-scale

    picture this way. Steganography goes well beyond

    simply embedding text in an image. It also pertains

    to other media, including voice, text, binary files,

    and communication channels.

    4. Experiments and Results This example is accomplished by applying the

    Least Significant Bit Insertion (LSB). Stego-keys

    are used to generate the stego-tables and table indices. In 24-bit images, to hide an image in the

    LSBs of each byte of a 24-bit image, you can store

    3 bits in each pixel (RGB). For example, the letter

    A can be hidden in three pixels (assuming no

    compression). The original raster data for 3 pixels

    (9 bytes) may be (the highlighted bits are the least

    significant bit in each byte):

    (00100111 11101001 11001000)

    (00100111 11001000 11101001)

    (11001000 00100111 11101001)

    The binary value for letter A is 10000011.

    Inserting the binary value for A in the three pixels

    would result as

    (00100111 11101000 11001000)

    (00100110 11001000 11101000)

    (11001001 00100111 11101001)

    The underlined bits are the only four actually changed in the 8 bytes used. On average,

    LSB requires that only half the bits in an image be

    changed. You can hide data in the least and second

    least significant bits and still the human eye would

    not be able to discern it. Here is an example in a

    large scale of 1024 x 768 Girl and Baboon cover

    image before embedding the encrypted data as

    shown in Figures-10 (a) and (b) respectively.

    Figure-10: Two RGB Cover Images (a) Girl (b)

    Baboon.

    A 1024 x 768 Girl image has the potential

    to hide a total of 2,359,296 bits (294,912 bytes) of

    information and a 1024 x 768 Baboon image has

    the potential to hide a total of 1,656,789 bits

    (207,099 bytes) of information. The relative

    entropy between the cover image and the stego

    image is zero. The resulting stego and the cover

    images should be indistinguishable by the naked

    eye. . Here is an example in a large scale of 1024

    x 768 Girl and Baboon cover image after

    embedding the encrypted data as shown in Figures-11 (a) and (b) respectively.

    Figure-11: Two Stego images Created by our

    approach (a) Girl (embedded data are 2,359,296

    bits (294,912 bytes)). (b) Baboon (embedded data

    are 1,656,789 bits (207,099 bytes)). An advantage of the proposed scheme is

    that the extracting algorithm is simple and easy to

    implement. When receiving a stego-image, the

    receiver uses the same stego-keys to generate the

    same stego-tables and table indices as those used in

    the embedding process to extract the originally

    encrypted data. Then decryption and

    decompression procedures are consequently done

    to obtain the plaintext. He also do the MAC check

    to be sure that the data is not modified through the

    communication channels. Some of the advantages

    of using K-bit LSB Steganography are:

    1) Gives high data embedding capacity.

    2) Provides high and imperceptible quality stego

    images.

    3) Provides high security.

    5. Conclusion & Future Enhancements In this paper, we presented an

    implementation to a package that contains many

    cryptosystems, hash functions, steganography and

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  • compression algorithms. This package might be

    used to deal to secure multimedia in

    communication channels as in the Internet.

    Hashing the key is used as a message

    authentication code (MAC). Cryptography and

    steganography methods are combined to make a

    robust model that can survive image manipulation

    and attacks. The more information that is made

    available on the Internet, the more owners of such information need to protect themselves from theft

    and false representation. The presented Secured

    Package Machinery achieved the two cryptographic

    principals objectives: (i) Secrecy (or privacy), to

    prevent the unauthorized disclosure of data and (ii)

    Authenticity (or integrity), to prevent the

    unauthorized modification of data.

    Steganographys function in security is to

    supplement cryptography, not replace it. If a

    message is encrypted and then embedded in an

    image, video, or voice, it becomes even more

    secure. If an encrypted message is intercepted, the

    interceptor knows the text is an encrypted message.

    Nevertheless, with steganography, the interceptor

    may not know that a hidden message even exists.

    The work accomplished during this project

    can be summarized with the following points: 1) In this project we have presented a new system

    for the combination of cryptography and

    Steganography using matrix mapping method for

    Symmetric Key Cryptography and modified BPCS

    technique for Steganography which could be

    proven a highly secured method for data

    communication in near future.

    2) Steganography especially combined with

    cryptography, is a powerful tool which enables

    people to communicate without possible

    eavesdroppers even knowing there is a form of

    communication in the first place. The proposed

    method provides acceptable image quality with

    very little distortion in the image.

    3) The main advantage of this

    Cryptosteganography System is hybrid

    combination of cryptography and Steganography which provides double layer security.

    In future video or audio files can be used

    to hide data instead of images.

    6. References [1] William Stallings; Cryptography and Network

    Security: Principals and Practice, Prentice Hall

    international, Inc.; 2002.

    [2] Oded Goldreich; Foundations of Cryptography,

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    Siegel, The International Handbook of Computer

    Security, Glenlake Publishing Company, Ltd.,

    Glenlake Publishing Company, Ltd., 2000.

    [4] H. M. Al-Barhmtoshy and Emad S. Ibrahim

    Key-Based Security Algorithm (KBSA), INFOS

    2002, Proceedings of the 1st International

    Conference on Information and systems, Cairo,

    Egypt, June, 2002.

    [5] Emad S. Ibrahim and Ahmed M. Gohar, An

    Encrypted Compression Model For Aerial Images,

    ICAIA 2003, proceedings of the 11th International

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    Cairo, Egypt, February, 2003.

    [6] Ma Shilong, Emad S. Ibrahim, and Hala A.

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    [7] Emad S. Ibrahim and Hala A. Bayoumy,

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    Systems, INES2003, Assiut - Luxor, Egypt, March,

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    [8] Emad S. Ibrahim and Ahmed M. Gohar,

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    [10] Neil F. Johnson, Zoran Duric, Sushil Jajodia,

    Information Hiding: Steganography and

    Watermarking - Attacks and Countermeasures,

    Kluwer Academic Publishers, 2000.

    [11] Ross J. Anderson, Fabien A.P. Petitcolas, On

    the Limits of Steganography, IEEE Journal of

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    [12] B. Pfitzmann, Information Hiding

    Terminology, Proc.First Intl Workshop

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    pp. 347-356. [13] Yeuan-Kuen Leea and Ling-Hwei Chen,

    High capacity steganographic model, IEE Proc.-

    Vis. Image signal Process., Vol. 147, No. 3, June

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    [14] http://www.jjtc.com/stegdoc/stegdoc.html.

    [15] E. Biham, A. Shamir. Differential

    cryptanalysis of DES-like cryptosystems, Journal

    of Cryptology, vol. 4, pp. 3-72, January 1991.

    [16] C. B. Smith and S. S. Agaian, On noise,

    steganography, and the active warden, Multimedia

    Forensics and Security, Chapter VIII, Information

    Science Reference, PA, 2008, pp. 139-162.

    [17] K. Kim, S. Park, and S. Lee, Reconstruction

    of s2DES SBoxes and their Immunity to

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