Reversible data hiding based on Shamir's secret sharing for color images over cloud

To reduce the vulnerability of the multimedia content against the wide attacking surface of the cloud-based paradigm, obscuring the information before dissemination becomes a necessary step. In this paper, a reversible data hiding scheme based on Shamir's secret sharing for rightful ownership verification in encrypted domain has been proposed. It obscures the cover information via distributing it into multiple random looking shares and embeds a secret information specific to the owner into some of these encrypted shares based on a secret key prior to outsourcing the media information to cloud servers. The shares reveal no information at the cloud servers and even if they get attacked at these cloud servers, the owner information can be extracted to provide the rightful ownership of the media. The scheme facilitates extraction of secret information either directly from the cloud servers or after recovery of the original media at the authentic entity end possessing the secret keys. The robustness of the scheme has been validated by considering different attack scenarios in the encrypted domain itself. The visual quality of the recovered media and the extracted secret information evaluated via peak signal to noise ratio (PSNR), normalized cross correlation metric (NCC) and structural similarity index (SSIM) prove the efficacy of the proposed scheme.