International Journal of Engineering and Technology

Data security has become an indispensable part with rapid progress in digital technology. Secret information particularly needs to be handled with utmost care while transmitting through internet or any other media as well. Out of many techniques for securing data Cryptography and Steganography are the most efficient methods. The latter hides the data whereas the former encrypts the data. In this paper we propose a new methodology that incorporates both these techniques to facilitate robust data security. The cover image is first encrypted using Arnold algorithm, and then the secret data which could be a text file or binary data is hidden using LSB substitution and Pixel Value Differencing (PVD) to embed data adaptively in the encrypted cover image to give near full-proof security. In order to increase PSNR optimisation technique Optimum Pixel Adjustment Process (OPAP) has been used.