The Study And Application On Multi-Secret Image Of Visual Cryptography

Visual cryptography is produced as a new research direction. It has been widely used in terms of secret sharing and information hiding. It has the characteristics of high safety and strongly concealment for image encryption of a special kind secret sharing scheme. The participants can restore the secret images by stacking the sharing images which do not need to master the knowledge of cryptography, what only need to do is using the human visual system. In recent years, with the development of visual cryptography, the study of visual cryptography is focused on parameter optimization, the color visual cryptography scheme, visual cryptography of the meaningful sharing image, multi-secret sharing visual cryptography and the application of visual cryptography. In this paper, we have studied several important directions in existing visual cryptography scheme, and the dissertation obtains main results as follows:In order to protect the copyright of 3D image, this paper has proposed a digital watermark scheme based on visual cryptography. Employing the methods of Anorld transform, DWT, quantization and plane sweep, the shares of encrypted watermark were embedded into the pretreated 3D image view images. The stimulation results showed that the scheme had the robustness of resisting JPEP compression, cropping, adding Gaussian noise, rotation and median filtering attack. The implanted watermark can't be extracted by 3D image directly, in which way the copyright security of 3D image is protected.The problem of information storage existed in traditional VCS. To improve the quantity of secret images when sharing the same amount of participants, this paper designed a MVCS based on the block separation. The scheme didn't utilize a pre-defined pattern book with expansion as others did, the rotation of matrix is used to encrypt the two secret images. There was no expansion in the proposed scheme, and the quality of image is pretty good.Aiming to solve the problem of biology information exposing of e-passport, this paper proposed an authentication system for e-passport based on VCS, which applied the fingerprint template in the daily life. One other fingerprint image is stored instead of the real one, in which way it can reduce the attention of the attackers, and the security of biology information is enhanced.