A novel bit plane based image sharing scheme using EVCS

A novel (k,n)-threshold image sharing scheme using Extended Visual Cryptography Scheme(EVCS) for grayscale images is proposed in this paper. In the sharing phase, the grayscale secret image is firstly decomposed into 8 bit planes which are viewed as 8 binary images. Each bit plane is encoded into n meaningful binary shadows using EVCS. By stacking the corresponding binary images in bit level, n meaningful grayscale shares are generated. In the revealing phase, the grayscale shares are decomposed into bit planes which are used to recover the secret bit planes. The secret grayscale image is reconstructed by the secret bit planes. The proposed algorithm has the advantage of perfect reconstruction of the secret image with low computation effort as well as easy recognition and management of the output shares when comparing to Lukac and Plataniotis´s scheme.