Lock and Key Share Secret Sharing Scheme with Meaningful Shares for Grayscale Image and Color Image

Objectives: The proposed scheme aims to present a secret sharing scheme (2, m, n) with lock and key shares, including meaningful shares for all lock and key shares. Methods: To create m lock and n key shares, the secret image will be encrypted. To retrieve the secret information from the recipient, any one share from the lock and another share from the key shares are used. When both shares are selected from either lock shares or key shares, no partial information about the hidden image is recovered. Meaningful shares do not disclose any information on the privacy of the picture data. The secret image at the recipient can have lossless reconstruction with minimal computation. Findings: The performance analysis of a proposed minimally computational secret sharing approach shows the structural similarity index (SSIM) as 1 and correlation as 1 which yields a reconstructed image that is exactly the same as the secret image. Typically, the secret image is reconstructed from meaningless shares using Boolean XOR. However, because attackers believe that secret information is concealed in meaningless shares, these shares are susceptible to share security breaches. Therefore, meaningful shares will improve the security of the share image. Novelty: The scheme provides a two-tier security model with meaningful shares for the secret image formats like grayscale and color images. Keywords: Visual cryptography, Meaningful shares, Two-tier security, Boolean operation, Information security