A construction method of (t,k,n)-essential secret image sharing scheme

Secret image sharing (SIS) is a technique to decompose a secret image into multiple shadows distributed to the corresponding participants. Only qualified subsets of the shadows can reveal the secret image. Usually all shadows have the same importance. However, in some application scenario, some shadows are accorded with the special privilege due to the status or importance of the corresponding participants. A (t, k, n) essential secret image sharing (ESIS) scheme share a secret image into n shadows including t essential shadows and n-t non-essential shadows. A qualified subset of the shadows should contain at least k shadows including all t essential shadows. In this paper, we propose a construction method of (t, k, n) essential secret image sharing (ESIS) scheme. In our scheme, all shadows have the size 1/k times of the secret image. It also resolves the problems in the previous ESIS schemes, such as different shadow sizes, concatenation of sub-shadows, using multiple SIS schemes and so on. Theoretical analyses and experimental results show that the proposed scheme is secure and effective.