Image Block-based Steganography using Varying Size Approach

Abstract

The field of data hiding in digital image processing becomes important as the use of public networks such as the Internet becomes popular and activities of spam increases. Various methods have been proposed and implemented in data hiding. Steganography is one such way to increase the security of messages over the internet. The least significant is one of the methods used in steganography. While most methods work bit by bit value or pixel by pixel value to hide the data. The one disadvantage of such methods is that there is low percentage of data that can be hidden. In this paper, a new algorithm has been proposed that works on blocks of images that are found same or similar in other image. As in today era, the size of digital images are quite large as compared to images used in early years of digital processing and the images contain randomized pixel having blocks of different sizes and variations in colors. This leads to similarity of block of one image with part of other image of same domain and the same approach is used to hide an image inside another image. In this regard, blocks of hiding image are matched up to maximum size m*n with parts of cover image.