A progressively essential secret image sharing scheme using hierarchy shadow

This paper presents an improved (t, s, k, n)-scalable essential secret image sharing based on Lagrange interpolation. In the proposed scheme, an image is shared to n participants in which s are essential. Any set of k or more shadows including a least t essential shadows can obtain the low-quality image, any set of k or more shadows including a least t essential shadows can recover the high-quality image. The more essential shadows to participate in the recovery, the more information of the secret image is obtained. While t = s, the entire secret image can be completely recovered. Even if the essential participants do not cooperate to recovery, k non-essential participants can also collaborate to obtain the low-quality image. Moreover, when an essential shadow is lost or destroyed, only the high-quality image recovery is influenced, meanwhile the low-quality image is still obtained. Compared with the previous similar literatures that some parts of the image cannot be recovered if one of the shadows is accidentally lost or maliciously attacked, our scheme is more suitable for the practical application. (C) 2019 Elsevier Ltd. All rights reserved.