P.Kavipriya et al Int. Journal of Engineering Research and Applications www.ijera.com ISSN : 2248-9622, Vol. 4, Issue 2( Version 2), February 2014, pp.26-28 www.ijera.com 26 | Page Color Secret Image Encryption and Share Generation for Multiple-Secret Threshold Visual Cryptography P. Kavipriya M.E 1 , Dr. M. Sangeetha 2 1 Student, Department of Computer Science and Engineering, Coimbatore Institute of Technology, Coimbatore, Tamil Nadu -641014 2 Assistant Professor (sr.gr),Department of Computer Science and Engineering, Coimbatore Institute of Technology, Coimbatore, Tamil Nadu -641014 ABSTRACT Visual Cryptography Scheme (VCS) is a type of secret sharing scheme which allows the encoding of a secret image into n shares that distributed to n participants. Each share constitutes some information and when k shares out of n stack together the secret will reveal. However; less than k shares are not work. The advantage of the visual secret sharing scheme is its decryption process i.e. to decrypt the secret using Human Visual System without any computation. Traditional Visual Cryptography suffers from share identification problem. This problem can be solved by Multiple-Secret threshold visual cryptography (MVCS), which adds a meaningful cover image in each share. The proposed work presents threshold Visual cryptographic schemes in Color Images. This method uses half toning method to provide color image as a secret image. Then the secret image can be embedded in the original image by generating shares using Zigzags scanning method. Experimental result of proposed system provides robust security than conventional visual cryptographic schemes. Keywords – Visual cryptography, Halftoning,Zig-Zag scanning. I. INTRODUCTION With the rapid evolution of communication technologies and computer networks, huge extents of digital data have been transmitted over the internet. However, transmission of secret data over an open channel can be easily forged, interfered or attacked by intruders. For security purpose, secret data is encrypted before transmission. Thus, the design of secret sharing schemes allows the secret to be shared among a group of participants has become an important research topic in modern security.The concept of threshold secret sharing was first proposed by Shamir and Blakley independently in 1979. Visual cryptography (VC) was first proposed by Naorand Shamir at Eurocrypt‟94. A visual secret sharing (VSS) scheme deals with the visual version of secret sharing where the shared secret is in the form of an image, the encoded shares are stamped on shares also called as transparencies, and the decoding process becomes the human visual recognition to the superimposed transparencies. Any set of shares reveals the secret image to the user when they are stacked together whereas any set of less than original reveals no information of the secret. Figure 1: Threshold Visual cryptography Fig. 1 shows a secret mage “CRYPT” creates a shares using (2,2)-threshold VSS scheme used to share the secret image „„As shown in figure 1, (b) and (c) gives meaningless shares. The secret image „„CRYPT” cannot be revealed by others with the obtained shares. Finally the secret image is revealed by the user by stacking the corresponding share which is shown in Fig1 (d). II. RELATED WORK Recently, various studies about visual cryptography are proposed. The following General access structures have been used for visual cryptographic schemes for generating shares. In [1],(2,n)-Threshold VCS is used .This encrypts the secret image into n number of shares such that any two shares can be combined then reveals the secret image. In [2].(n,n)-Threshold VCS is used. In this the secret image can be encrypted into n shares such that when all n shares are combined RESEARCH ARTICLE OPEN ACCESS