Visual cryptography

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

A Novel Copyright Protection Scheme Using Visual Cryptography

Abstract: Visual cryptography scheme is a cryptographic technique which allows visual information to be encrypted in such a way that the decryption can be performed by the human visual system, without the aid of computers. In this article, we propose a novel scheme for copyright protection for digital images based on visual cryptography. The proposed method employs encoding of Most Significant bits of host image which is to be copyrighted, to form a master image share. The master share is encoded with a copyright image to form another share called ownership share. The master share is kept with a central authority and ownership share is kept by the copyright owner. In case of any dispute, the master shares and ownership shares can be stacked together to give the copyright image verifying the ownership about the host image. The important feature of our procedure is that we don not disturb the host image either during copyright generation nor during copyright verification. The proposed method is also independent of the size of secret image.

An Exploitation of Visual Cryptography to Ensure Enhanced Security in Several Applications

Abstract: VC is a cryptographic technique that ensures the security of images by dividing a secret image into random shares, which makes the image data unreadable. Then decryption is performed by superimposing the shares, without any special computational power. Intuitively, VC can be categorized as: secret sharing scheme [1] for monochrome images and extended VC (EVC) [2] for color images. In this paper both schemes of VC have been exploited to hide image where image security is essential, such as Bangla text document, hand-written signature, biometric authentication (e.g. human face) etc. These can be exercised in offices for deed, in banking sector for financial document and in examination or election system for authentication respectively. Moreover a minor modification of EVC which can be applied for color image also has been presented. General Terms Visual Cryptography, User Authentication.

Binary Image Visual Cryptography

Abstract: Modern computer networks make it possible to distribute documents quickly and economically. This is because of the decreasing cost of the equipment needed to copy, print, process the information. The widespread adoption of electronic distribution of material is accompanied with more emphasis on data security. One of the modern data security methods is Visual Cryptography. Visual Cryptography(VC) is the technique that is used for securing data specially image-based secrets such as credit card information, personal health information, military maps and personally identifiable information and commercial identification data.

Optical image encryption scheme with extended visual cryptography and non-mechanical ptychographic encoding

Abstract: Non-mechanical ptychographic encoding (NPE) transforms the secret information into series of diffractive patterns through a spatial light modulator (SLM), saving the need to fabricate the secret objects. Conventionally, the shares in extended visual cryptography (EVC) are printed on transparent sheets or fabricated with diffractive optical elements and metasurface, but these methods are expensive and disposable. To solve these problems, we proposed an optical image encryption scheme that combines EVC and NPE. In the encryption process, the secret image is decomposed into multiple shares that are digitally loaded on the SLM, and the ciphertexts are generated according to the ptychographic encoding scheme. The decryption is performed by superimposing the shares reconstructed from the ciphertexts. We present optical experiments to demonstrate the feasibility and effectiveness of the proposed method.

A Novel Hybrid Discrete Cosine Transformation and Visual Cryptographic Technique for Securing Digital Images

Abstract: Security of digital images in today's cyber is a major concern. Transmission of compressed and uncompressed multimedia data is necessary for communication between different devices. Devices of different screen features and resolution need very efficient and fast compression techniques in order to maintain visual features of transmitted media. Robustness is of a key consideration and importance in image compression techniques. Full recovery of images after compression is a challenge for image compression algorithms. It is practically closely impossible for most encrypted-compressed-images or compressed-encryptedimages to be efficiently and fully reconstructed. In this paper we proposed a robust, efficient and fully recoverable encrypted-compressed image based on hybrid discrete cosine transformation and visual cryptographic technique for securing digital images. We first encrypted the image without pixel loss and then compressed the image which resulted into pixel loss during the compression phase. We decrypted the compressed image by obtaining perfect visuals but losses in pixel values. The analysis of the process proved to be an efficient way of encrypting images and compressing them for other channels with less data capacity without the worry of visual loss as well as ensuring security of the data during transmission. The programming and implementation was done using MATLAB.