A Novel Hierarchical Threshold Secret Image Sharing Scheme

In this paper, we propose a novel hierarchical visual cryptography scheme to protect secret image by designing secret sharing and recover procedures. The polynomial coefficients are generated using the projection matrix method, and shadows are generated for different levels of participants based on the Birkhoff interpolation method. The proposed hierarchical secret sharing processes and recover processes are proposed in detail by mathematical design, utilizing the random matrix to generate the polynomial coefficients and generating quite different secret shadow image to each participant. Security analysis and experiments prove that the proposed scheme is effective and can defend fake shadow attacks and collusion attacks.