Secured Transmission with Enhanced Security for Grayscale Images using Visual Cryptography

Security has gained a lot of importance with the rapid development of communication/storage technology. Protecting the data has become an important issue. In this paper a transmission system with enhanced security is proposed for the image information. Here, the secret image is encrypted and transmitted by using a combined technique that make use of Discrete Wavelet Transform (DWT), Visual Cryptography (VC) and Water marking. DWT is first used for the compression of the secret image. Visual cryptography encodes the compressed image into noise like shadow images known as shares. Shares are made invisible by digital watermarking, which provides additional security. By stacking the shares together, the secret image can be visually decoded. Different image types are used to evaluate the performance of the proposed scheme. Comparison with different values of scaling parameter M, which is used to decrease the size of image in the VC is also done. The results clearly indicate that the proposed scheme can send more data with less bandwidth more secretly.