A hierarchical threshold secret image sharing

In the traditional secret image sharing schemes, the shadow images are generated by embedding the secret data into the cover image such that a sufficient number of shadow images can cooperate to reconstruct the secret image. In the process of reconstruction, each shadow image plays an equivalent role. However, a general threshold access structure could have other useful properties for the application. In this paper, we consider the problem of secret shadow images with a hierarchical threshold structure, employing Tassa’s hierarchical secret sharing to propose a hierarchical threshold secret image sharing scheme. In our scheme, the shadow images are partitioned into several levels, and the threshold access structure is determined by a sequence of threshold requirements. If and only if the shadow images involved satisfy the threshold requirements, the secret image can be reconstructed without distortion.

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► We propose a secret image sharing which has hierarchical access structure.
► Shadow images are partitioned into some levels, and each level has its threshold.
► Secret image can be recovered when the shadow images satisfy the access structure.
► The scheme can solve the problems of overflow and underflow.
► The embedding capacity and the visual quality of the shadow images are satisfied.