A New High Capacity and Reversible Data Hiding Technique for Images

The growth in the internet has paved the way for an increase in digital communication. Cryptography and data hiding provide security of the data being communicated. In cryptography, the fact that the information is hidden is not concealed, whereas, in data hiding, it is hard to tell if a cover media contains embedded information. Data hiding can be used for covert communication, or to embed extra information about the image. Often the original cover image cannot be restored once the embedded data has been extracted. However, for certain applications like those belonging to medical and military, the data hiding process cannot distort the cover image. Medical images contain important diagnostic information, and military images serve some legal purpose. Any change in these images can lead to negative consequences. Therefore, a data hiding mechanism is needed for applications in which both the image as well as the data being hidden are important to hide data in such a way which will enable the extraction of embedded data and also restore the original image. Reversible data hiding (RDH) techniques have been proposed to embed data in such sensitive images. In this paper, we discuss a histogram shifting based two pass RDH scheme. Experimental results illustrate that the proposed technique, other than being reversible provides fairly high quality marked image along with high embedding capacity.