Threshold Visual Cryptographic Scheme With Meaningful Shares

摘要

In a conventional threshold $k$ out of $n$ visual cryptographic scheme (($k,n$)-VCS, for short), one secret image $P$ can be encoded into $n$ seemingly random transparencies (called shares) such that the superimposed result of any group of $k$ or more transparencies can reveal $P$ to our eyes, while that of less than $k$ ones cannot. To ease the management and identification, the shares may look meaningful, instead of seemingly random, pictures. Given secret image $P$ shared by $n$ participants and cover image $C$, we study ( $k, n$)-VCS with meaningful shares (denoted as ($k, n$)-VCS-MS) in this letter where the $n$ shares could be recognized as the meaningful cover $C$ and their superimpositions follow the threshold requirements of ($k, n$)-VCS. We present a formal definition to ( $k, n$)-VCS-MS and develop an efficient construction by way of integer line- r programming. Experimental results demonstrate the effectiveness of our construction.