Properties of Images in LSB Plane

Abstract

Each pixel of an Image (assuming 24 bit BMP) is stored in the three 8 bits corresponding to three colors. Bit Plane Slicing is the technique of breaking image into 8 planes corresponding to 8 different bit positions. The bit plane image corresponding to the plane of the most significant bit (MSB) has the maximum contribution to the total image and forms the majority of the visually significant image data and planes corresponding to other lower bit positions contribute only the subtle details of the image. And the bit-plane image corresponding to the LSB of the RGB value has the minimum contribution of only 1 out of total of 255 Intensity level to the total image. In spite of this the LSB Plane of the image is not insignificant. In fact it is used in Image Steganography for hiding secret information in the images. Image based Steganography is a potent tool used by Terrorists and Criminal organizations for securely broadcasting, dead-dropping and communicating malicious secret messages over the internet by hiding them in the images. Our cyber space is full of such mala-fide images containing hidden secret information. The most difficult aspect of tracking such malicious images is the lack of efficient and fast algorithms for identifying and isolating them from the bulk of innocent images. Analysis of the pixels in the LSB Plane of the image is very effective technique of identification of Distributing Spatial Domain Steganographic Algorithms. In this paper the properties of Information Pixels pixel present in the LSB Plane of any stego image generated by Distributing Algorithms is analyzed in detail. These properties will be very useful in identification of malafide stego images lurking in our cyber space. All the images and tables used in this paper are generated using MATLAB ©Image Processing Tool Box.