Improved (k, n) visual secret sharing based on random grids

Abstract

(k, n) Visual secret sharing (VSS) is a cryptographic procedure in which secret information in the form of images is encoded into ‘n’ shares (or shadow images) such that secret is recovered only if ‘k’ or more shares are superimposed, whereas superimposing not as much as ‘k’ shares provides no information regarding secret. In this paper, (k, n) VSS based on random grids is proposed which requires no design for codebook and does not involve pixel expansion. The proposed scheme produces better results in terms of improved contrast which decides visual quality. Many experiments are executed to assess the efficacy and security of the proposed approach. The proposed scheme is compared with existing schemes to show its benefits.