Visual cryptography

About: Visual cryptography is a research topic. Over the lifetime, 1724 publications have been published within this topic receiving 25300 citations.

Extended visual cryptography scheme with aspect ratio invariant

Abstract: Conventional visual cryptography scheme (VCS) generates noise-like random pixels on shares to hide secret images by expanding a secret pixel to m sub pixels. m is not a square integer, and results in the distortion of recovered image. Most existing aspect ratio invariant VCSs generated share images are meaningless. It suffers a management problem which dealers cannot visually identify each share. In this paper, we firstly analyze the property of the extended matrix. Then we present a construction which implements the meaningful shares with aspect ratio invariant based on the above property. And our scheme like the original extended visual cryptography scheme (EVCS) does that every secret pixel is exactly reconstructed. The pixel expansion and the contrast of recovered image approximately equals convention VCS under the premise of keeping the aspect ratio invariant.

Secure data encryption and authentication using Visual Cryptography in the TSVCE algorithm

Abstract: In today's nature transmitting message in a safe and protected miniature is difficult, especially when decidedly conscious message is involved. The system aspiration at suggested a methodology which employs dual stage of examination getting cryptography and steganography to cover the mysterious document message. The Visual cryptography system (VCS) is a protected mode that encoded a mysterious image into shares. The key design behind the suggested access deals with message hiding in image getting Zigzag scanning pattern which is more complex method Z 2 H in steganography again encoded as shares by VC technique for hidden in separate cover images to present authentication for the VC shares which makes these mysterious shares invisible by hidden them into cover images getting (Two Shares Visual Cryptographic Encryption) TSVCE method. The mysterious shares generated from VC encryption are watermarked into some cover images getting digitized watermarking. Digitized watermarking is used for providing the dual examination of image shares. The share is embedded into the cover image getting Least Significant Bit Insertion Technique (LSB). The system presents more protected and meaningful mysterious shares that are robust against a total of attacks. The performance of the suggested system is evaluated getting peak signal to noise ratio (PSNR), histogram analysis and also numerical experimentation suggests that hidden time varies linearly with message length. The simulation results show that, the suggested system presents high stage of examination. Index Terms- Zigzag, Mysterious shares, Visual cryptography, Watermarking, Cover images.

Secure visual secret sharing based on discrete wavelet transform

Abstract: Visual Cryptography Scheme (VCS) is an encryption method to encode secret written materials. This method converts the secret written material into an image. Then encode this secret image into n shadow images called shares. For the recreation of the original secret, all or some selected subsets of shares are needed; individual shares are of no use on their own. The secret image can be recovered simply by selecting some subset of these n shares, makes transparencies of them and stacking on top of each other. Nowadays, the data security has an important role. The shares can be altered by an attacker. So providing security to the shares is important. This paper proposes a method of adding security to cryptographic shares. This method uses two dimensional discrete wavelet transform to hide visual secret shares. Then the hidden secrets are distributed among participants through the internet. All hidden shares are extracted to reconstruct the secret.

A Study of Image Fingerprinting by Using Visual Cryptography

Abstract: As digital media has made our life more colourful because of its advantages like easier to access, copy and distribute. But as what we have seen, series of malice activities like copyright infringement, counterfeiting, piracy and information distortion make damages to both the producers and the users of digital products. So we really need some technology to protect the copyright, authenticity, integrity of the digital products and the intellectual property of the users. There are many techniques such as Digital watermarking and Visual Cryptography both have been widely used for protection of data either in text, video, sound or digital images form in modern network time. Digital watermarking is an evolving field that requires continuous effort to find for the best possible method in protecting multimedia content. But Visual Cryptography is a special encryption technique to hide information in images in such a way that it can be decrypted by the human vision if the correct key image is used. Both techniques addresses the growing concerns of theft and tampering of digital media through the use of advanced signal processing strategies to embed copyright and authentication information within media content in their respective manner. In this paper we have discussed image fingerprinting with the help of visual cryptography technique. Keywords: Authentication, Digital Media, Digital Watermarking, Fingerprinting, Image, Piracy, Visual Cryptography