On the (2,2) Visual Multi-Secret Sharing Schemes

Abstract

The concept of visual secret sharing (VSS) scheme was first proposed by Noar and Shamir in 1994. This is a technique to divide a secret image into several meaningless images, called shadows, such that certain qualified subsets of shadows can recover the secret image by “eyes”. The main characteristic of VSS schemes is that its decoding process can be perceived directly by the human visual system without the knowledge of cryptography and cryptographic computations. It possesses a special meaning and effect that “the secret codes are visible”. In this paper, we propose a new Visual Multi-Secret Sharing (VMSS) scheme. The main difference between VMSS scheme and traditional Visual Secret Sharing (VSS) scheme is that it is allowed to hide more than one secret in VMSS while VSS can hide only one secret. We give an optimal generating codebook of (2,2) VMSS scheme and discuss the security of the proposed scheme. The characteristic of the (2,2) VMSS scheme is to conceal two secret messages (P1 and P2) on two shadows such that P1 is recovered by stacking together the two shadows. However, P2 is recovered by reversing one of the two shadows.