Data Hiding Using Steganography

Data Hiding Using Steganography

Abstract:

It is a truth universally acknowledged that “a picture is worth a thousand words”. The emerge of digital media has taken this saying to a complete new level. By using steganography, one can hide not only 1000, but thousands of words even in an averagesized image. This article presents various types of techniques used by modern digital steganography, as well as the implementation of the least significant bit (LSB) method. The main objective is to develop an application that uses LSB insertion in order to encode data into a cover image. Both a serial and parallel version are proposed and an analysis of the performances is made using images ranging from 1.9 to 131 megapixels.

Introduction:

Throughout time, confidentiality has always been important. Whether it is carved in stone, written on paper or sent over the Internet, correspondence between two persons is exposed to tampering or eavesdropping. Therefore, it is necessary to provide a mechanism that protects written information. One of the most common methods of securing transmitted data is cryptography. The purpose of cryptography is to disguise plaintext in such a way that it becomes unreadable. The resulted text, called cyphertext can then be safely transmitted to the destination. Knowing the algorithm used for encryption, only the receiver will be able to obtain the original message. Access to powerful computers does not only mean better encryption. It can equally be a tool used for breaking a cipher or decrypting a message. No matter how powerful the encryption algorithm is, encrypted data will always arouse suspicion. This is where steganography can help. Steganography can be defined as “the art and science of communicating in a way which hides the existence of communication” [1]. Although cryptography and steganography are often confounded, they are essentially different. Whilst the first one “scrambles a message so it cannot be understood”, the other one “hides the message so it cannot be seen” [2]. It is commonly believed, mistankenly , that steganography could replace cryptography. On the contrary, by using the two techniques together one can create a solid and powerful encryption system, better than each of the two components. With digital data as a mean of communication, messages can be hidden in the ones and zeros of text files, pictures, audio or video files. However, in order for the message to remain secret, only certain bits can be used. Hence, before the beginning of the information-hiding process,  the stenographic. system must identify the redundant bits - those bits that can be modified without altering the integrity of the file [3]. After this step, the least significant bits from the cover medium can be replaced with data that has to be hidden.

Proposed method:

The goal of this project was to implement an application that uses the LSB steganography method in order to hide and recover data. Because communication involves a sender and a receiver, there are two ways in which the application can run: as an encoder or as a decoder. For the encoding part the message is hidden into the least significant bits of an image, thus resulting the stego-image. This image is then given to the decoder to extract the data that has been hidden.

Applications:

• To protect information most secret
• Confidential communication and secret data storing
• Protection of data alteration
• Secret communication in defense applications

Tools Required:

      Matlab 7.5 , Matlab 10a