Security enhanced random grid visual cryptography scheme using master share and embedding method

Visual cryptography scheme is one of the main branches of secret sharing. The image is converted into various shares and then recouped by overlapping the required number of shares. In this paper, a master share based on random grid visual cryptography is generated and then embedded in to a cover image. Traditional visual cryptography scheme based on random grids require 2n shares to transfer n secret images. The proposed method only requires (n + 1) shares as the master share is considered to be common to all shares. The method provides multiple layers of security as the master share is safeguarded by embedding method. The key advantages of random grid algorithms are that the pixel expansion and codebook design issues are averted. The analysis and demonstrated experiments proved that the method is more secure and efficient when compared to existing techniques of visual cryptography and steganography.