A Comparable Study of Hiding Information in Images Using Least Significant Bit (LSB) Substitution and Pixel Value Differencing (PVD) Methods

Steganography is one of the most powerful techniques that conceal the existence of hidden secret data inside a cover object. In this thesis, we take an image for a carrier of secret data which is known as a host or cover image. After embedding the secret data into the host image, the output image of this hiding process is called a stego-image, data hiding schemes are used, by applying some pixel adjustment process to the stego-image obtained by the simple LSB substitution method, and using PVD method, the image quality of the stego-image can be greatly improved with low extra computational complexity. The mean-square-error between the stego-image and the cover-image and Peak Signal to noise ratio are computed. Experimental results show that the stego-image is visually indistinguishable from the original cover-image. As we make a comparable study, the results show that PVD method gives a better image quality combined with the capacity of hidden data, as well as the complexity and robustness of embedded data are increased where the secret data is stored in a difficult way to understand by any intruder.