Graph access structures with optimal pixel expansion three
Let G=(V,E) G = ( V , E ) be a graph without isolated vertices. Let ?(G) ? ( G ) denote the strong access structure whose basis is the edge set E  and let m?(G) m ? ( G ) denote the optimal pixel expansion of a visual cryptography scheme for ?(G) ? ( G ) . In this paper we obtain a characterization of all connected graphs G  with m?(G)=3 m ? ( G ) = 3 .
pixel expansion strong access structure visual cryptography scheme relative contrast