An information hiding technique based on visual cryptography

Visual Cryptography was first proposed by Moni Naor and Adi Shamir in Eurocrypt’94. They demonstrated a (t, n) visual secret sharing scheme, in which visual information is encoded into n shares so that only someone with t or more than t shares could decrypt this visual information, while nothing would be revealed by any t-1 shares. Particularly, the decryption is performed directly by stacking shares and the concealed information is gained by human visual system without any cryptographic computations. Additionally, a keyed (t, n) visual secret sharing scheme is also considered, in which some specific shares, called keyed shares, must be involved to recover the visual information. Without the help of the keyed shares, no information will be retrieved. Information hiding is the art of imperceptibly embedding some information into the digital work and getting it more or less modified as a result. In this paper, we design a scheme in which the redundancy in visual secret sharing scheme is employed for embedding additional information. According to the similar concept, information hiding technique based on the (2, 2), (2, 3), (3, 3) visual secret sharing schemes and (2, 3) keyed visual secret sharing scheme are proposed. From the experimental results, the proposed schemes not only contribute the functionality of visual cryptography, but also provide with the ability of information hiding.