RGB are subjected to encryption and decryption. II.Earlier

RGB Based Multiple Share Creation in Visual




Sethulakshmi Unnikrishnan

Department of Computer Science and Technology Adi shankara Institute of Engineering and Technology, Kalady Kerala,India

Email:[email protected]



Ms Divya D

Department of Computer Science and Technology Adi shankara Institute of Engineering and Technology, Kalady Kerala,India

Email:[email protected]




 In the art of visual cryptography, many shares are generated which are illogical containing certain message within themselves. When all shares are piled jointly, they tend to expose the secret of the image. The notion of visual secret sharing scheme is to encrypt a secret image into n illogical share images. It is unable to reveal any data on the original image if at least one of the shares is not achieved. The original image, in fact, is realized by overlapping the entire shares directly, in order that the human visual system is competent to identify the collective secret image without employing any complicated computational tools. Therefore, they are communicated steadily as number of shares. The elliptic curve cryptography approach, in turn, is employed to augment the privacy and safety of the image. The new-fangled technique is utilized to generate the multiple shares which are subjected to encryption and decryption.



II.Earlier methods used:

A. Black And White Visual Cryptography Schemes

Naor and Shamir’s proposed an encryption scheme to convert a binary image into two shares. In this scheme each share pixel p is encoded into two white and two black pixels each share alone gives no clue about the pixel p whether it is white or black. Secret



image is visible only when both shares are stacked on each other. Visual secret sharing schemes based on the Threshold value of mixed XOR and OR operation with reversing and based on binary linear error- correcting code

The main disadvantage of this schemes is that it can only be used for one set of confidential messages can be embedded, therefore for large amounts of confidential messages several shares have to be generated.

B. Color Visual Cryptography Schemes

Until the year 1997 visual cryptography schemes were applied to only black and white images. First colored visual cryptography scheme was developed by Verheul and Van Tilborg . A colored secret images can be shared with the concept of arcs to construct a colored VCS. In colored VCS one pixel is converted into m subpixels, and each subpixel is further divided into c color regions. In each subpixel, there is exactly one color region is colored, and other color regions are black. The color of one pixel depends on the interrelations between the stacked subpixels.

This scheme offers a perfect reconstruction while producing shares with size smaller than the size of input image using maximum separable distance. This scheme provides pixel expansion less than one.

C. Extended Visual Cryptography Schemes

The term of the extended visual cryptography scheme (EVCS) was first introduced by Naor in , where a simple example of (2,2) -EVCS was presented. One scenario for the applications of EVCS is to avoid the customs inspections, as the shares of EVCS are meaningful images, therefore there are less chances for the shares to be detected.

D. VCS for General Access Control

VCS for a general access structure with Multi-pixel encoding is one of the emerging method in visual cryptography that can encode more than one pixel for each run. However, its encoding efficiency is not much fast enough. In this scheme it offers a novel multi-pixel encoding that can encode in a variable number of pixels for each run. The encoding length at one run is equal to the number of the successive same pixels met during scanning the secret image. Proposed scheme works well for the  general access structure for chromatic images without pixel expansion. The experimental result shows that it can achieve high efficiency for encoding and good quality of overlapped images.

E. Visual Cryptography Schemes using Compressed Random Shares:

In this, the system uses a known compression scheme for the security of the secret shares in place of the embedding process as it increases the execution time of the entire system and it also degrades the quality of the regenerated image. It also does not provide the reduction of the size of the covering shares in any way. This system also provides an integrated environment to process the images. Most of existing cryptography tools support only single image format. The application can process .gif and .png (portable network graphics) formatted images and it is developed using Java technology, hence provides a simple user interface.


Introduction Elliptic Curve Cryptography Technique:

In this proposed methodology we are going to see


·         Share creation

·         Encryption (Elliptical Curve Cryptography)

·         Decryption (Elliptical Curve Cryptography


Share Creation:

·         Each original pixel of the secret image is appeared in ‘n’ modified versions called shares.

·         Each share is a collection of sub-pixels of the RGB image. Each R, G, B shares are based on the pixel values of the RGB image.

·         The shares are created on the basis of  splitting the image into various regions. The secret sharing scheme is to encrypt a secret image into n meaningless share images.