Visual cryptography

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

A Survey on Random Grid based Cryptography Schemes

Abstract: A random grid based non-expanded Visual cryptography scheme used to generate meaningful as well as meaningless shares. First, analyze the distribution of pixels on the share image and stack image. A probability allocation method is introduced which is capable of producing the better visual quality in share image and stack image. With this method, it not only hide the secret image by using different cover images, but also visual quality of images is improve as needed. The important part is improvement of contrast of both secret and stack images to their theoretical maximum. This method is superior to past methods for visual secret sharing.

Cognitive approaches for patterns analysis and security applications

Abstract: In this paper will be presented new opportunities for developing innovative solutions for semantic pattern classification and visual cryptography, which will base on cognitive and bio-inspired approaches. Such techniques can be used for evaluation of the meaning of analyzed patterns or encrypted information, and allow to involve such meaning into the classification task or encryption process. It also allows using some crypto-biometric solutions to extend personalized cryptography methodologies based on visual pattern analysis. In particular application of cognitive information systems for semantic analysis of different patterns will be presented, and also a novel application of such systems for visual secret sharing will be described. Visual shares for divided information can be created based on threshold procedure, which may be dependent on personal abilities to recognize some image details visible on divided images.

V-CRYPT: A Secure Visual Cryptography System

Abstract: Nowadays, peoples are very concerned about their data privacy. Hence, all the current security methods should be improved to stay relevant in this fast-growing technology world. Visual Cryptography (VC) is a cryptographic technique that using the image processing method. The implementation of VC can be varying and flexible to be applied to the system that requires an extra security precaution as it is one of the effective solutions in securing the data exchange between two or more parties. The main purpose of the development of V-CRYPT System is to improve the current VC technique and make it more complex in the encryption and decryption process. V-CRYPT system will let the user enter the key, then select the image that they want to encrypt, and the system will split the image into four shares: share0, share1, share2, share3. Each pixel of the image will be splatted into a smaller block of subpixels in each of the four shares and encrypted as two subpixels in each of the shares. The decryption will work only when the user selects all the shares, and the correct text key is entered. The system will superimpose all the shares and producing one perfect image. If the incorrect key is entered, the resulted image will be unidentified. The results show that V- CRYPT is a valuable alternative to existing methods where its security level is higher in terms of adding a secure key and complexity.

Visual cryptography for color images

Abstract: Visual cryptography is a secret sharing scheme for encrypting a secret image, it is a perfectly secure way that allows secret sharing without any cryptographic computation, which is termed as Visual Cryptography Scheme (VCS). In this paper secret image is divided into shares (printed on transparencies), and each share holds some information. At the receiver this shares are merged to obtain the secret information which is revealed without any complex computation. The proposed algorithm is for color host image, divided into three color planes Red, Green, Blue and merged with secret image which is binarized and divided into shares. The decoding requires aligning the result obtained by merging color host image and shares, so as to obtain the secret image. Keywords-component: visual cryptography; secret shari.

Collusive Attacks to Partition Authentication Visual Cryptography Scheme

Abstract: In order to preventing cheating attack, partition authentication visual cryptography scheme (PAVCS) was proposed, in which each authentication pattern can be revealed on the stacked result of the corresponding partitions of any two shares. Without needing extra share, a PAVCS not only accomplishes sharing a secret image, but also provides mutual authentication of every two shares. In this paper, we propose two types of collusive attacks to (k, n)-PAVCS. The aim of the first type of attack is to destroy the integrity of the secret image revealed by victims, while the second type of attack belongs to cheating attack. Experimental results and theoretical analysis show that the two types of collusive attacks are successful attacks. Furthermore, we put forward the suggestion to devise partition authentication visual cryptography scheme for resisting the proposed two types of collusive attacks.