Image Security Using Visual Cryptography

Introduction

A secret is piece of information or collection of data which is kept from the knowledge of any but the initiated or privileged. Secret contents are used in various fields such as, education, entertainment, manufacturing, logistics, healthcare and medicine. So the protection of secret content is very crucial in the modern internet communication. Secret sharing is an extra special method as compared to conventional scheme. Secret sharing is a process which a secret can be distributed between groups of participants, whereby each participant is allocated a piece of the secret. This piece of the secret is known as a share. The secret can only be reconstructed when a sufficient number of shares are combined together. While these shares are separate, no information about the secret can be accessed. That is, the shares are completely useless while they are separated. Within a secret sharing scheme, the secret is divided into a number of shares and distributed among n persons. When any k or more of these persons (where k ≤ n) bring their shares together, the secret can be recovered. However, if k - 1persons attempt to reconstruct the secret, they will fail. Secret sharing involves four major steps, which is shown in Table 1.