Novel Image Steganography Based on Preprocessing of Secrete Messages to Attain Enhanced Data Security and Improved Payload Capacity

Image steganography hides secret messages in cover images by manipulating their content. There is a fundamental requirement of maximizing secrecy and payload capacity. This paper presents a novel algorithm for achieving two layer security as well improved payload capacity by prepossessing the secret images before hiding it in a cover image. The secret image is divided in to small windows of fixed sizes and is searched from a database of 255 images. Each window of secret image is replaced by the address of its closet match in database. Instead of hiding a secret image this algorithm hides the address of database. Consequently makes it impossible for any third party to retrieve the secret image without having access to the database. The size of the database address is less than the size of secret message thus it improves the payload capacity of the proposed algorithm.