An Implementation of LSB Steganography Using DWT Technique

Steganography is the art or practice of concealing a message, image, or file within another message, image, or file. In steganography, there is a technique in which the least significant bit is modified to hide the secret message, known as the least significant bit (LSB) steganography. Least significant bit matching images are still not well detected, especially, at low embedding rate. In this paper, we have improved the least significant bit steganalyzers by analyzing and manipulating the features of some existing least significant bit matching steganalysis techniques. This paper explains the LSB Embedding technique with lifting based DWT schemes by using Micro blaze Processor implemented in a FPGA using System C coding. Keywords— DWT, FPGA, LSB, Micro Blaze, Steganography. Introduction The art or practice of concealing a message, image, or file within another message, image, or fileis called Steganography. The word steganography combines steganos meaning "co-vered, concealed, or protected", and graphein meaning "writing". Generally, the hidden messages will appear to be (or be part of) something else: images, articles or some other cover text. Steganalysis develops theories, methods and techniques that can be used to detect hidden messages in multimedia docu-ments. The documents without any hidden messages are called cover documents and the documents with hidden messages are denoted by stego documents. In steganography, there is a technique in which the least significant bit is modified to hide the secret message, this technique is known as the least significant bit (LSB) steganography or LSB embedding. A digital image is described using a 2-D matrix of the intestines at each grid point (i.e. pixel). Typically, gray images use 8 bits, whereas coloured utilizes 24 bits to describe the colour model, such as RGB model. The steganography system which uses an image as the cover object is referred to as an image steganography system. The shift from cryptography to steganography is due to that concealing the image existence as stego-images enable to embed the secret message to cover images. Steganography conceptually implies that the message to be transmitted is not visible to the informal eye. Steganography has been used for thousands of years to transmit data without being intercepted by unwanted viewers. It is an art of hiding information inside other information. The main objective of Steganography is mainly concerned with the protection of contents of the hidden information. Images are ideal for information hiding because of the large amount of redundant space is created in the storing of images. Secret messages are transferred through unknown cover carriers in such a manner that the very existence of the embedded messages is undetectable.Carriers include images,audio,video,text or any other digitally represented code or transmission.The hidden message may be plaintext or another as a bit stream. 2. THE LSB TECHNIQUE We have implemented the LSB steganography algorithm in gray scale images to reduce the complexity of the system. It is the process of embedding data within the domain of another data, this data can be text, image, audio, or video contents and the scope of the current paper covers only codes (integer values). The embedded data is invisible to the human eye i.e., it is hidden in such a way that it cannot be retrieved without knowing the extraction algorithm. In this paper we evaluated the technique using gray scale images of size International Journal of Engineering Research and General Science Volume 2, Issue 6, October-November, 2014 ISSN 2091-2730 399 www.ijergs.org 64*64 in which each pixel value was represented with 8 bit representation. Example: Take the number 300, and its binary equivalent is 100101100 embedded into the least significant bits of pixel values of the Cover image. If we overlay these 9 bits over the LSB of the 9 bytes cover image pixel values, we get the following (where bits in bold have been changed) 10010101 0000110