A Study on Various Secret Data Embedding Techniques in Digital Images for Secure Communication

Covert communication using images is relatively very young and fast growing field combining image and signal processing with cryptography, communication theory, coding theory, signal compression, and the theory of visual perception. Image steganography aims at hiding the very presence of communication, to make the communication undetectable. This is done by adding secret data in a suitable multimedia cover, e.g., image, audio, and video files. There exists various techniques to embed secret data in images. Different image file formats have different embedding schemes, with their own advantages and disadvantages. In this paper a study on available secret data embedding techniques in an image file in various spatial domain and frequency domain techniques are done along with masking and filtering techniques. Techniques for the recovered image quality assessment is also discussed in this paper since performance of each embedding techniques is assessed by the quality of recovered image and the distortion less extraction of secret data.