Improved Algorithm for Visual Cryptography Using Region Incrementation

1 Region incrementing visual cryptography is used to hide multiple secrecy levels in a single image. In n level region incrementing visual cryptography scheme, image is divided in n regions. Each region consists of one level information. For implementing visual cryptography in n levels we need to encode (n+1) shares in such a way so that any single share is not able to show the information and by combining any two shares, first level information would be visible. Similarly by superimposing any three shares, information upto second level could be seen. In similar way, for revealing whole information all the (n+1) shares are superimposed. These n levels are created according to user specification. In proposed scheme, user does not need to address the area of different levels manually and levels are created automatically. User needs only to use a particular level information with a particular size of text. The traditional region incrementing visual cryptography scheme has been modified to address the problem of pixel expansion and poor contrast. In proposed algorithm, problem of pixel expansion and poor contrast has been removed and further it is modified to generate the levels automatically which is named as automatic region incrementing visual cryptography.