Steganography and Steganalysis of JPEG Images

My research motivation came from a project supported by Naval Research Laboratory (NRL) where I was working on an algorithm to provide better stealthiness for hiding data inside JPEG images. As a result, with the guidance of my advisor, Dr. Newman, and Ira S. Moskowitz from Center for High Assurance Computer Systems, NRL, we developed J2 steganography algorithm which was based on hiding data in the spatial domain by making changes in the frequency domain. J2 had problems such as lower capacity along with no first order histogram restoration. This led to the development of J3 where the global histogram is preserved along with higher capacity. But, the first order preservation is not enough since it can be detected using higher order statistics. I plan to develop an algorithm where I could maintain the first and second order statistics in stego images with respect to cover image. In order to develop a good steganography algorithm, one should have knowledge about the different steganalysis techniques. Keeping this in mind, I also plan to propose a steganalysis scheme where I would estimate the cover image using the second order statistics. My research goals focus on the following topics: 1. Designing a frequency based embedding approach with spatial based extraction using hash of the data from spatial domain, J2. (Done) 2. Designing a novel approach to high capacity JPEG steganography using histogram compensation technique, J3. (Done) 3. Designing a JPEG steganography algorithm using first and second order statistical restoration techniques with high performance in terms of steganalysis, J4. (Work in progress) 1 4. Designing a steganalysis scheme based on estimation of cover using the second order statistics. (Work in progress) 5. Improvement over features of J2 and J3 and analyzing more experimental results for steganalysis using Support Vector Machines. (Work in Progress) 2 Contribution We developed two techniques to embed data in the JPEG medium. The first one, called J2, embeds data by making changing to the DCT coefficients which in turn makes changes in the spatial domain values. The extraction is done by converting JPEG to spatial domain and hashing the values of the bits from the color pixels. Second algorithm, which was a great improvement over J2, called J3, has a high capacity and it embeds data with great efficiency and better stealthiness. It also has the ability to restore the histogram completely to its original values. The third algorithm, as …