A cellular automata-based multi-stage secret image sharing scheme

A new Multi-Stage Multi-Secret Image Sharing (MSMSIS) scheme, based on polynomial sharing and cellular automata, is proposed in this paper. The proposed scheme shares multiple secret images among a number of players. The shares and the authentication strings, produced by a cryptographic hash function, are then embedded in cover images by an XOR-based operation in such a way that visual and statistical quality of covers are preserved as much as possible. A particular type of cellular automata is used to guarantee that the secrets are only recovered according to a pre-specified order. The scheme is multiuse, since some parameters are distributed only once and used multiple times. The scheme is verifiable as well, because a cryptographic hash function is used in each stage for each secret image separately. Generality of our scheme also implies that it can be applied on a heterogeneous set of different secret formats, where each secret has its own access structure. Based on our experiments, the PSNR of the proposed method is improved almost 11 percent compared to the average PSNR of the previous similar schemes.