Ramp secret image sharing

Abstract

Secret image sharing (SIS) belongs to but differs from secret sharing. In general, conventional (k, n) threshold SIS has the shortcoming of pall-or-nothingq. In this article, first we introduce ramp SIS definition. Then we propose a $(k_1, k_2, n)$ ramp SIS based on the Chinese remainder theorem (CRT). In the proposed scheme, on the one hand, when we collect any $k_1$ or more and less than $k_2$ shadows, the secret image will be disclosed in a progressive way. On the other hand, when we collect any $k_2$ or more shadows, the secret image will be disclosed losslessly. Furthermore, the disclosing method is only modular arithmetic, which can be used in some real-time applications. We give theoretical analyses and experiments to show the effectiveness of the proposed scheme.

Keywords

• secret image sharing
• ramp secret image sharing
• chinese remainder theorem
• progressiveness
• lossless recovery