We propose a visual cryptography scheme (VCS) for two parties  and  In this scheme, every participant receives a sheet, and when two participants belonging to different parties stack their sheet together, a hidden secret image is recovered. This scheme is called a visual cryptography scheme of -type, here  denotes the complete bipartite graph. In this paper, we propose constructions of visual cryptography scheme of -type with contrast  and that of -type with contrast  for  are provided. Next we prove that the contrasts of these constructions are maximum, if  Moreover, explicit construction of VCBG of -type with pixel expansion 2rand contrast  is proposed for all  and it is shown that this pixel expansion is minimum.

graph based, visual cryptography scheme.