A Visual Cryptography Based Digital Image Copyright Protection

A method for creating digital image copyright protection is proposed in this paper. The proposed method in this paper is based on visual cryptography defined by Noor and Shamir. The proposed method is working on selection of random pixels from the original digital image instead of specific selection of pixels. The new method proposed does not require that the watermark pattern to be embedded in to the original digital image. Instead of that, verification information is generated which will be used to verify the ownership of the image. This leaves the marked image equal to the original image. The method is based on the relationship between randomly selected pixels and their 8-neighbors’ pixels. This relationship keeps the marked image coherent against diverse attacks even if the most significant bits of randomly selected pixels have been changed by attacker as we will see later in this paper. Experimental results show the proposed method can recover the watermark pattern from the marked image even if major changes are made to the original digital image.

RGB Based Multiple Share Creation in Visual Cryptography with Aid of Elliptic Curve Cryptography

In visual cryptography, many shares are generated which are illogical containing certain message within themselves. When all shares are piled jointly, they tend to expose the secret of the image. The notion of visual secret sharing scheme is to encrypt a secret image into n illogical share images. It is unable to reveal any data on the original image if at least one of the shares is not achieved. The original image, in fact, is realized by overlapping the entire shares directly, in order that the human visual system is competent to identify the collective secret image without employing any complicated computational tools. Therefore, they are communicated steadily as number of shares. The elliptic curve cryptography approach, in turn, is employed to augment the privacy and safety of the image. The new.fangled technique is utilized to generate the multiple shares which are subjected to encryption and decryption by means of the elliptic curve cryptography technique. The test outcomes have revealed the fact that the peak signal to noise ratio is 58.0025, Mean square error value is 0.1164 and the correlation coefficient is 1 for the decrypted image without any sort of distortion of the original image.

Construction of General (k, n) Probabilistic Visual Cryptography Scheme

Visual cryptography scheme （VCS） is a secure method that encrypts a secret image by subdividing it into shadow images. Due to the nature of encryption VCS is categorized into two types： the deterministic VCS （DVCS） and the probabilistie VCS （PVCS）. For the DVCS, we use m （known as the pixel expansion） subpixels to represent a secret pixel. The PVCS uses only one subpixel to represent a secret pixel, while the quality of reconstructed image is degraded. A well-known construction of （k, n）-PVCS is obtained from the （k, n）-DVCS. In this paper, we show another construction of （k, n）-PVCS by extending the （k, k）-PVCS.

Securing Technique Using Pattern-Based LSB Audio Steganography and Intensity-Based Visual Cryptography

With the increasing need of sensitive or secret data transmission through public network,security demands using cryptography and steganography are becoming a thirsty research area of last few years.These two techniques can be merged and provide better security which is nowadays extremely required.The proposed system provides a novel method of information security using the techniques of audio steganography combined with visual cryptography.In this system,we take a secret image and divide it into several subparts to make more than one incomprehensible sub-images using the method of visual cryptography.Each of the sub-images is then hidden within individual cover audio files using audio steganographic techniques.The cover audios are then sent to the required destinations where reverse steganography schemes are applied to them to get the incomprehensible component images back.At last,all the sub-images are superimposed to get the actual secret image.This method is very secure as it uses a two-step security mechanism to maintain secrecy.The possibility of interception is less in this technique because one must have each piece of correct sub-image to regenerate the actual secret image.Without superimposing every one of the sub-images meaningful secret images cannot be formed.Audio files are composed of densely packed bits.The high density of data in audio makes it hard for a listener to detect the manipulation due to the proposed time-domain audio steganographic method.

A Secure Visual Cryptography Scheme Using Private Key with Invariant Share Sizes

Visual cryptography (VC) is one of the best techniques used to secure information. It uses the human vision to decrypt the encrypted images without any cryptographic computations. The basic concept of visual cryptography is splitting the secret image into shares such that when the shares are stacked, the secret image is revealed. In this paper we proposed a method that is based on the concept of visual cryptography for color images and without any pixel expansion which requires less space. The proposed method is used to encrypt halftone color images by generating two shares, random and key shares which are the same size as the secret color image. The two shares are generated based on a private key. At the receiving side, the secret color image is revealed by stacking the two shares and exploiting the human vision system. In this paper, we produce an enhanced form of the proposed method by modifying the encryption technique used to generate the random and the key shares. Experimental results have shown that the proposed and the enhanced methods suggest an efficient way to encrypt a secret color image with better level of security, less storage space, less time of computation and with a better value of PSNR.

Dual Visual Cryptography Using the Interference Color of Birefringent Material

Visual cryptography is a method of encrypting an image into several encrypted images. Conventional visual cryptography can display only monochrome images. We previously proposed a color visual cryptography method that uses the interference color of high-order retarder films and encrypts one secret image into two encrypted images. In other words, this method can only encrypt one image at a time. In this paper, we propose a new method that encrypts two color images using interference color.

A DIGITAL SIGNATURE-BASED VISUAL CRYPTOGRAPHY SCHEME FOR IMAGE DISCRIMINATION AND MANAGEMENT

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.

MULTI-WATERMARKING SCHEME FOR GROUP USERS BASED ON VISUAL CRYPTOGRAPHY

All watermarks are shared into shadow images using VCS(Visual Cryptography Scheme). Only one specific shadow (as a new watermark) is embedded into the host signal and the other ones are distributed to every user in each group as a key. In the watermarking extraction procedure, users in different group can obtain different watermark by combining their shadows with the extracted one from the watermarked signal. Analysis and experimental results show that the new watermarking method is novel, secure and robust.

Color Visual Cryptography with Stacking Order Dependence Using Interference Color

Visual cryptography is an encryption method that shares a secret image through several encrypted images. General visual cryptography has no stacking order dependence, and only one image can be decoded regardless of stacking order of encrypted images. We previously reported a color visual cryptography using interference color (or polarization color) of retarder films. The interference color changes depending on the stacking order of retarder films. In this paper, we propose and develop a color visual cryptography that displays two images by changing stacking order of retarder films.

用VC＋＋和Visual Foxpro实现基于ActiveX数据通讯

利用自动服务器ActiveX Automation，可以在VC++中与Visual Foxpro进行数据通讯。通过自动服务器，成功地解决了各种数据类型的交换问题。

Secret Sharing Using Visual Cryptography

Compared with the traditional crypto- graphy, visual cryptography （VC） decrypts secret images referring to the characteristics of human vision, rather than the cryptography knowledge or complex computations. Furthermore, seeing to the freeness of the secret key, the whole process of encryption as well as deeryption for the visual cryptography meets a fast dealing course. As to the security concern, it is able to guarantee that no one can have access to any clues about the content of a secret image from individual cover images. Thus, owing to the studies on this area, the target of light-weighted cryptography is reached. Now the visual cryptography has been developed from the meaningless shadows to the meaningful ones. Seeing to the highly developed technique, some advanced VC techniques are introduced in this survey, respectively.

Video Identification Based on Watermarking Schemes and Visual Cryptography

Related to the growth of data sharing on the Internet and the wide-spread use of digital media,multimedia security and copyright protection have become of broad interest.Visual cryptography(VC)is a method of sharing a secret image between a group of participants,where certain groups of participants are defined as qualified and may combine their share of the image to obtain the original,and certain other groups are defined as prohibited,and even if they combine knowledge of their parts,they can’t obtain any information on the secret image.The visual cryptography is one of the techniques which used to transmit the secrete image under the cover picture.Human vision systems are connected to visual cryptography.The black and white image was originally used as a hidden image.In order to achieve the owner’s copy right security based on visual cryptography,a watermarking algorithm is presented.We suggest an approach in this paper to hide multiple images in video by meaningful shares using one binary share.With a common share,which we refer to as a smart key,we can decrypt several images simultaneously.Depending on a given share,the smart key decrypts several hidden images.The smart key is printed on transparency and the shares are involved in video and decryption is performed by physically superimposing the transparency on the video.Using binary,grayscale,and color images,we test the proposed method.

Secret Image Communication Scheme Based on Visual Cryptography and Tetrolet Tiling Patterns

Visual cryptographic scheme is specially designed for secret image sharing in the form of shadow images.The basic idea of visual cryptography is to construct two or more secret shares from the original image in the form of chaotic image.In this paper,a novel secret image communication scheme based on visual cryptography and Tetrolet tiling patterns is proposed.The proposed image communication scheme will break the secret image into more shadow images based on the Tetrolet tiling patterns.The secret image is divided into 4×4 blocks of tetrominoes and employs the concept of visual cryptography to hide the secret image.The main feature of the proposed scheme is the selection of random blocks to apply the tetrolet tilling patterns from the fundamental tetrolet pattern board.Single procedure is used to perform both tetrolet transform and the scheme of visual cryptography.Finally,the experimental results showcase the proposed scheme is an extraordinary approach to transfer the secret image and reconstruct the secret image with high visual quality in the receiver end.

VB、VC++、VisualFORTRAN程序对MATLAB的调用

介绍了VB、VC++、VisualFORTRAN编制的软件中通过ActiveX使用MATLAB的方法。

Usability and Security of Arabic Text-based CAPTCHA Using Visual Cryptography

Recently,with the spread of online services involving websites,attack-ers have the opportunity to expose these services to malicious actions.To protect these services,A Completely Automated Public Turing Test to Tell Computers and Humans Apart(CAPTCHA)is a proposed technique.Since many Arabic countries have developed their online services in Arabic,Arabic text-based CAPTCHA has been introduced to improve the usability for their users.More-over,there exist a visual cryptography(VC)technique which can be exploited in order to enhance the security of text-based CAPTCHA by encrypting a CAPTCHA image into two shares and decrypting it by asking the user to stack them on each other.However,as yet,the implementation of this technique with regard to Arabic text-based CAPTCHA has not been carried out.Therefore,this paper aims to implement an Arabic printed and handwritten text-based CAPTCHA scheme based on the VC technique.To evaluate this scheme,experi-mental studies are conducted,and the results show that the implemented scheme offers a reasonable security and usability levels with text-based CAPTCHA itself.

Preventing Phishing Attack on Voting System Using Visual Cryptography

Phishing is one of the most common social engineering attacks that users over the internet fall for. An example is voting systems, and because such systems should be accurate and error free, phishing prevention techniques are crucial. Visual Cryptography (VC) is utilized for efficient voting system authentication to cast votes. VC is one of the most secure approaches for privacy protection as it ensures the confidentiality of the voting system. This paper discusses proposed phishing prevention methods and compares different proposed methods.

Clarity Corresponding to Contrast in Visual Cryptography

The visual quality of the recovered secret image is usually evaluated by contrast in visual cryptography (VC). Precisely, the reconstructed secret image can be recognized as the original secret image when contrast is greater than zero. It is important for the user to know the clarity of the revealed secret image corresponding to different contrast values. In this paper, the clarity corresponding to contrast is investigated through conducting subjective evaluation scores and objective evaluation indexes, which can be extended to general applications.

Web Application Authentication Using Visual Cryptography and Cued Clicked Point Recall-based Graphical Password

Alphanumerical usernames and passwords are the most used computer authentication technique.This approach has been found to have a number of disadvantages.Users,for example,frequently choose passwords that are simple to guess.On the other side,if a password is difficult to guess,it is also difficult to remember.Graphical passwords have been proposed in the literature as a potential alternative to alphanumerical passwords,based on the fact that people remember pictures better than text.Existing graphical passwords,on the other hand,are vulnerable to a shoulder surfing assault.To address this shoulder surfing vulnerability,this study proposes an authentication system for web-applications based on visual cryptography and cued click point recall-based graphical password.The efficiency of the proposed system was validated using unit,system and usability testing measures.The results of the system and unit testing showed that the proposed system accomplished its objectives and requirements.The results of the usability test showed that the proposed system is easy to use,friendly and highly secured.

第3章 Visual C＋＋网络与通信编程实例——例题23 用VC＋＋设计网络应用程序

本文通过一个分布的网络应用程序的设计，来理解网络套接字（Socket）的应用知识，了解并熟悉用VC＋＋编写WinSock网络应用程序的过程和方法。

基于MATCOM的VC与MATLAB集成应用研究

论述了 Visual C++6.0与 MATLAB集成应用的特点、意义 ,介绍了 VC++环境下基于 MATCOM集成应用系统的开发环境、系统软件配置、开发方法、步骤 。