A self-verifiable computational visual cryptographic protocol for secure two-dimensional image communication

A visual secret sharing (VSS) scheme is an image encryption technique for the secure transmission of multimedia visual information. A VSS divides the secret into a number of image shares. The shares are distributed to the participants either as meaningless or meaningful shares. VSS has been applied to support secure transmission of military, medical and financial documents and so on. No individual share discloses the secret message. One of the drawbacks of VSS is that if an intruder happens to modify or change the share, the reconstructed secret image cannot be verified for its integrity. Other factors such as security and quality are also considered to be a significant concern. Traditional VSS schemes verify the integrity of the reconstructed image with additional shares, or with a trusted third party. The security of the image integrity also needs to be considered. This article proposes a new self-verifiable computational visual cryptographic protocol (SCVCP) that facilitates a computational model to overcome issues of integrity verification. The SCVCP maintains the secure transmission of meaningful shares without compromising the quality of the reconstructed image. The experimental results show that the SCVCP is secure and robust against quality issues without complex computations. The SCVCP verifies the authenticity of the reconstructed two-dimensional image without any extra shares. The verification ensures the integrity of the secret message at the revealing stage while reconstructing the secret image. (paper)