An Extended Region Incrementing Visual Cryptography Scheme Using Unexpanded Meaningful Shares

Abstract

Region Incrementing Visual Cryptography (RIVC) is an important and active research area. In (2, n) region incrementing visual cryptographic scheme, a single secret image is divided into multiple secret regions. We need at least 2 secret shares to be superimposed to reveal the 1st secret region. By stacking more and more shares we get the entire image revealed. All the existing schemes for RIVCS suffer from the problems like color reversal, pixel expansion and low contrast. Also conventional RIVCS schemes generate noise like shares. The management of these shares is also problem, as there is no way to identify these shares. Thus we are proposing a new Extended RIVC scheme which uses the characteristics of both RIVCS and Extended VCS which adds a meaningful cover image to the shares. Our proposed method solves all the above mentioned drawbacks of the existing schemes. The main contributions in this paper are: a) No pixel expansion b)Meaningful share images c)Increased contrast d) No color reversal e) Improved Security.