Visual cryptography

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

Method of share generation for color visual cryptography

Abstract: Visual secret sharing is the technique that divide the secret image into n multiple shares. Each share constitutes some information and when k shares out of n stack together the secret will reveal. However; less than k shares are not work. Color visual cryptography (VC) is a scheme of providing security to a color secret image by encrypting it into n color halftone image shares. A visual cryptogram scheme consists of an encryption algorithm by which a secret image is divided into a set of shares and a decryption algorithm which is used to recover the secret image by staking the shares. This paper introduced the concept of visual information pixel (VIP) synchronization and error diffusion to attain a color visual cryptography encryption method that produces meaningful color shares with high visual quality. VIP synchronization retains the positions of pixels carrying visual information of original images throughout the 3 color channels and error diffusion diffuses the errors, generates shares pleasant to human eyes.

A digital signature-based visual cryptography scheme for image discrimination and management

Abstract: Visual cryptography is a cryptographic technique which emerges in the information security domain in recent years. Each of the sharing sub-keys may be a stochastic noise image or a significative image with no information on the original key. But a mass of sub-keys have to be saved actually, which faces the problem of inconvenient discrimination and management. This paper presents a visual cryptography scheme based on the digital signature for image discrimination and management, applying the digital signature and the time-stamp technology to the visual cryptography scheme. The scheme both solves the problem on the storage and management of the sharing sub-keys, increases the verification of image contents, thus enhances the validity of storage and management without security effect.

Enhancement in Security Using Extended Security Techniques

Abstract: Security has become an inseparable issue as internet is ruling the world. Every day we are doing various activities such as e-banking, e-shopping or information transfer through internet so there exists a need for safe and secure transactions. Extended visual cryptography is very advanced technique for providing security to information which will be going to transfer through network. In this paper, we exploit extended visual cryptography technique for military application security. Without sending password directly as it is from sender to receiver we are going to create shares of password and those shares will be transfer through secure server to receiver. When receiver will combine this shares then only complete password will be revealed. In this paper we provide overview of extended visual cryptography and Algorithms implementation is presented in this paper for share generation of password.

Visual Cryptography Scheme for Colored Image using XOR with Random Key Generation

Abstract: Visual Cryptography (VC), 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 (HVS), without the help of computers. Visual Cryptography Scheme (VCS) eliminates complex computation problem in decryption process, by stacking operation we can restore the secret image. This property makes VC especially useful for the low computation load requirement. During encryption, the image is encrypted and then it is divided into two shares. Two shares are superimposed to reveal the secret image in the decryption process. The objective of our project is to get the better quality of decrypted image with the same size as the original image. The OR based VCS degrades the contrast by its monotone property. In XOR based scheme, the share images are superimposed with the help of XOR operation which results in perfect reconstruction. Hence, the XOR operation is proposed in decoding process to enhance the contrast, quality, and to reduce noise.

Lossless Compression of VC Shares in RGB Color Space

Abstract: 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. In Visual Cryptography the reconstructed image after decryption process encounters a major problem of Pixel expansion. This is overcome in this proposed method by minimizing the memory size using lossless image compression techniques. Image compression is minimizing the size in bytes of a graphics file without degrading the quality of the image to an unacceptable level. The reduction in file size allows more images to be stored in a given amount of disk or memory space. It also reduces the time required for images to be sent over the Internet or downloaded from Web pages. Hybrid techniques are used in this proposed method as it can exploit multiple kinds of redundant information Keywords: Visual Cryptography; HVS; Image Compression; Vector Quantization; Run Length Encoding; Huffman Coding