Abstract: Information is increasingly important in our daily life. Information gets more value when shared with others. Due to advances in technologies related to networking and communication, it is possible to share the information like audio, video and image easily. It may give rise to security related issues. Attackers may try to access unauthorized data and misuse it. To solve this problem certain techniques are required. Techniques to provide security, while sharing information are termed as Secret sharing schemes. When it comes to visual information like image and video, it is termed as Visual secret sharing scheme. Visual cryptography (VC) is a technique used for protecting image-based secrets. The basic concept of visual cryptography scheme is, to split secret image into some shares, which separately reveals no knowledge about the secret information. Shares are then distributed to participants. By stacking these shares directly, secret information can be revealed and visually recognized. All shares are necessary to combine to reveal the secret image. The best part is secret image is revealed by overlaying the shares without any complex computation involved. Starting from the basic model, many visual cryptographic techniques have been evolved day by day. An extended visual cryptography scheme (EVCS) is a kind of VCS which consists of meaningful shares (compared to the random shares of traditional VCS). In this paper, I propose a construction of EVCS which is realized by embedding random shares into meaningful covering shares, and it is called embedded EVCS. Experimental results compare some of the well-known EVCSs proposed in recent years systematically, and show that the proposed embedded EVCS has competitive visual quality compared with many of the well-known EVCSs in the literature. In addition, it has many specific advantages against these well-known EVCSs, respectively. In this paper I propose, an invisible watermarking technique is proposed, to embed multiple binary watermarks into digital medical images based on the concept of Visual Cryptography (VC). The proposed scheme embeds the watermarks without modifying the original host image.
Keywords: Information security, Secret sharing scheme, Visual Cryptography, Data hiding