Image Steganographic Systems using Transforms

Steganography is used to hide information in some other medium to provide protection against detection. The success of a technique lies in changing the cover medium in a way that makes the change imperceptible for both the human and computer. A major limitation of steganography is the size of the cover medium used. Therefore, all the Steganographic methods aim to achieve higher hiding capacity in a given medium. Images however, offer a wide variety of ways in which additional information could be embedded. The major dimensions in which images can be used are spectrum, Least Significant Bit (LSB) substitution and transformed domain steganography. The transformed domain steganography techniques are more robust and difficult to detect as compared to LSB insertion. There are few techniques available for color image steganography because, most of the color image formats like jpeg are larger in size and communicating heavy images over open systems like internet can raise suspicions.This book, therefore, provides three steganographic systems based on wavelet/contourlet transforms and Blowfish encryption for improved image steganography using different image sizes of JPEG format.