Plane-Wise Encryption Based Progressive Visual Cryptography for Gray Image

Abstract

Visual secret sharing is a powerful technique, which allows to diffuse and disguise a secret image into two or more shares. To reconstruct the secret image these shares are stacked and viewed by the human visual system. Unluckily, Visual cryptography is not in primary use because of the degradation process entails severe problems in reconstructed image quality. Degradation reflects in terms of pixel expansion and loss in contrast, which makes visual cryptography unsuitable to handle visual information (image, video etc.) for the purpose of sharing and protection. The visual secret sharing techniques performed computation in order to absolve reconstructed secret image from pixel expansion and loss in contrast. Progressive visual cryptography (PVC) inherits all the advantageous features of traditional visual cryptography except the decryption process. In PVC, contrast of the reconstructed secret image increases gradually as the number of stacked shares increase but quality of reconstructed secret images still an issue for the researchers. To resolve the issue, this paper proposes a plane-wise encryption based progressive visual cryptography scheme for gray image. The effectiveness of the proposed scheme are carried out by experimental results and compared with state of the art approaches. Experimental results show that proposed scheme is well suited for applications where quality of secret image is a major issue.