T. Anuradha et al, International Journal of Computer Science and Mobile Computing, Vol.3 Issue.9, September- 2014, pg. 134-140 © 2014, IJCSMC All Rights Reserved 134 Available Online at www.ijcsmc.com International Journal of Computer Science and Mobile Computing A Monthly Journal of Computer Science and Information Technology ISSN 2320–088X IJCSMC, Vol. 3, Issue. 9, September 2014, pg.134 – 140 RESEARCH ARTICLE Comparative Analysis on Visual Cryptographic Schemes T. Anuradha 1 , K. Usha Rani 2 ¹Research Scholar, Department of CS, Sri Padmavathi Mahila Viswavidyalayam, Tirupati, India ²Professor, Department of CS, Sri Padmavathi Mahila Viswavidyalayam, Tirupati, India 1 a_talasila@yahoo.com; 2 usharanikiruba@yahoo.co.in Abstract — Visual cryptography is the techniques that deal with providing security to the multimedia data. The main concept behind this is, to encrypt a secret image into some shares. The secret can be revealed only when all the shares are combined. The central theme of visual cryptography is that it doesn’t require any manipulation or tough cryptographic knowledge and the decryption is done by human vision without the help of computers. Thus, visual cryptography is known for its least computational complexity yet much secure. In this work, we compared traditional visual cryptography, extended visual cryptography and colour extended cryptography with respect to PSNR, NCC and MSE. On analysis, it is found that the performance of colour extended visual cryptography is much better than the traditional visual cryptography and extended visual cryptography, in terms of Peak Signal to Noise Ratio (PSNR), Normalized Correlation Coefficient (NCC) and Mean Square Error (MSE). Keywords— Visual Cryptography, Extended Visual Cryptography, colour extended visual cryptography, PSNR, NCC, MSE I. INTRODUCTION The present era can be called as an era of data, as everyone deals with the multimedia data. Obviously, the multimedia data is transferred through the networks, which are prone to several security breaches. Proper care has to be rendered while transferring important secret images, as the adversaries may hack the data. Visual cryptography is the techniques that deal with providing security to the multimedia data. Visual Cryptography is a technique used to protect image based secrets. The main concept behind this is, to encrypt a secret image into some shares. The secret can be revealed only when all the shares are combined. Thus, this scheme is very effective. Visual cryptography hides secrets within images. These images are encoded into multiple shares and decoded afterwards without any computation. Visual cryptography is an emergent cryptographic methodology, which is proposed by Naor and Shamir [1]. The central theme of visual cryptography is that it doesn’t require any manipulation or tough cryptographic knowledge and the decryption is done by human vision without the help of computers. Thus, visual cryptography is known for its least computational complexity yet much secure [2]. Visual cryptography safeguards image based secrets. In this scheme, a secret image is encrypted into certain shares. The secret image can be made known, only when all the shares are available, i.e. a secret image cannot be identified with some shares. The secret image can be accessed after stacking all the shares. In this paper, a survey about visual cryptography is presented.