A privilege-based visual secret sharing model

• The first paper discusses the privilege concept in visual cryptography.
• A model is proposed to help the design of the sharing matrices.
• High privilege participant has better capability to reveal the secret image.
• The restored image has better contrast than other researches.

In traditional visual secret sharing (VSS) schemes, every transparency has the same capability for recovery of the secret image. This means that managers are unable to assign an appropriate privilege to participants according to their importance. One way to solve this problem would be to assign each share a suitable recovery capability. In this study, we propose a novel secret sharing method, the privilege-based visual secret sharing model (PVSSM), which allows participants with different privileges. It is assumed that participants having a higher privilege will have a higher ability to recover the secret image. The proposed PVSSM has the following advantages: (1) Each share has an appropriate capability to reveal the secret information corresponding to the privilege of the share holder. (2) The restored image has a better contrast than the traditional VSS method can achieve. (3) The share has the same size as the secret image.