A New Visual Cryptography Technique for Color Images
Abstract - Visual Cryptography (VC) is an emerging cryptography technology that uses the characteristics of human vision to decrypt encrypted images. This cryptographic system encrypts it by dividing a secret image into n number of share and decryption is done by superimposing a certain number of share (k) or more. The secret information can be retrieved by anyone only if the person gets at least k number of share. No clue about a secret image is revealed if less than k-1 share are superimposed. The Visual cryptography technique is not only applied for binary messages, grayscale images, but also for color images such as scenic photos or pictures. Color visual cryptography (VC) is used to generate a color halftone image share by encrypting a color secret image. In order to preserve the visual quality and size of the color share without expansion, the concept of size invariant Visual Secret Sharing (VSS) scheme and error diffusion is introduced. Experimental result shows that the proposed method can improve the reconstructed image quality compared with previous techniques. Also, it produces clearer and higher contrast for all kinds of color images.
Index Terms — Error Diffusion, Halftone, Size invariant VSS, Visual cryptography, Visual secret sharing.
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International Journal for Trends in Technology & Engineering © 2015 IJTET JOURNAL