A Novel Two Stage Binary Image Security System Using ( 2 , 2 ) Visual Cryptography Scheme

Visual Cryptography Scheme (VCS) is an encryption method used to encode secret written materials. The idea is to convert the written material into a binary image and encode this image into n shadow image, it is also called as shares of images. The decoding only requires selecting some subset of these n shadow images, making transparencies of them and stacking them on top of each other. Main advantage of this scheme is mathematical computation complexity is reduced compared to conventional cryptographic techniques. This paper presents design of two stage binary image security scheme using (2,2)Visual Cryptography Technique such that we are not able to get back the original image at the first decoding stage. As the cryptographic algorithm becomes more relevant, it will become inefficient. So, the basic model of Visual Cryptography is not an efficient tool to hide the information anymore. This method aims to improve efficiency of VCS. The performance of proposed algorithm is compared with three different binary images. Result shows that there is no residual information present in the shares. Key word: Visual Cryptography Scheme, LFSR, Binary Image Security.