A stegano-visual cryptography technique for multimedia security

Owing to the increasing growth in digital communication as well as the multimedia applications, security has now become a very significant problem in the communication as well as storage space of such images. The Visual Cryptography (VC) has been used for hiding the information that are in the images which is a special technique of encryption that is decrypted by a human visual system. In this paper, a technique for embedding a secret message within that of a cover-image to ensure the interceptors will not observe the presence of such hidden data is presented. The method has an essential conception by means of a simple Least Significant Bit (LSB) substitution. Being inspired by the steganography approach, the current work splits the cover images into n blocks of 8X 8 pixels and into a secret message of n partitions in order to improve the image quality and to increase the capacity of secret message along with its security level. For the purpose of improving this stego-image quality and for increasing the capacity of secret message along with its security level, being inspired by the current work that splits cover images into the n blocks of 8X 8 pixels and into a secret message of n partitions. In the proposed method, the Cuckoo Search (CS) is used for searching an approximate and optimal solution of finding any optimal substitution matrix to transform the message in every block as opposed to finding a single optimal matrix for substitution and the entire cover-image is presented. The final quality of its resulting in the stego-image, and its secret message and its capacity with the level of security of this method proposed will be calculated and then comparted to the other different methods. The results of the experiment proved that the proposed method outperformed all the Joint Photographic Experts Group (the JPEG) and the Joint Quantization Table Modification (the JQTM) based method in terms of quality of image, security level and embedding capacity.