Visual cryptography

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

Multi-secret Visual Cryptography Based on Reversed Images

Abstract: By reversing secret images, a novel multi-secret visual cryptography scheme is presented in this paper During the secret sharing process, the correlative matrices are designed to encode multiple images into two ring shares Compared with the previous ones, the proposed scheme makes the number of secret images not restricted and has obviously improved the pixel expansion and the relative difference

Online Payment System using Steganography and Visual Cryptography

Abstract: A rapid growth in E-Commerce market is seen in recent time throughout the world. With ever increasing popularity of online shopping, Debit or Credit card fraud and personal information security are major concerns for customers, merchants and banks specifically in the case of CNP (Card Not Present). This paper presents a new approach for providing limited information only that is necessary for fund transfer during online shopping thereby safeguarding customer data and increasing customer confidence and preventing identity theft. The method uses combined application of steganography and visual cryptography for this purpose. Keywords—Information security; Steganography; Visual Cryptography; Online shopping

Watermarks and Text Transformations in Visual Document Authentication

Abstract: Integrity of digital documents is a very important issue if they are to be legally binding. Common solutions, like digital signatures or message authentication codes, are based on cryptography and require computers or similar hardware to be produced. They can be trusted only as long as the employed hardware can be trusted. We present a complementary scheme for document authentication in untrusted environment. The scheme combines visual authentication, human- recognizable watermarks, and image transformations, and is suitable also for larger text document. Because it relies on visual cryptography, it requires practically no computational power on the receiver side. To prevent potential attackers from obtaining signatures without author’s knowledge, we propose using a simple challenge-response protocol.

A review on visual cryptography schemes

Abstract: Visual cryptography scheme is a cryptographic technique which allows visual information (e.g. printed text, handwritten notes, and picture) to be encrypted in such a way that the decryption can be performed by the human visual system, without the aid of computers. There are various measures on which performance of visual cryptography scheme depends, such as pixel expansion, contrast, security, accuracy, computational complexity, share generated is meaningful or meaningless, type of secret images( either binary or color) and number of secret images(either single or multiple) encrypted by the scheme. Intent of this paper is on study and performance analysis of the visual cryptography schemes on the basis of pixel expansion, number of secret images, image format and type of shares generated.

Dot-Size Variant Visual Cryptography

Abstract: In this paper, we propose a scheme by which a secure random share can be generated using a dot-size variant form of visual cryptography (VC). We generate two extended style VC shares, when the share is viewed, it appears as a normal random visual cryptography share. However, this scheme is designed with spatial filtering in mind, this is the dot-size variant part of the scheme. Dot-size variant means that instead of having single black and white dots which make up a VC share, we use a cluster of smaller dots to represent these black and white pixels. This means that after printing, if the share is scanned or photocopied or even viewed with a mobile phone or digital camera, the smallest dots in the scheme are filtered. This loss of information during the copying process allows the original share to have additional security in that accurate copies cannot be created, as well as the fact that due to this loss, the copied share looks totally different from the original. This technique can be used to detect possible counterfeit shares and copies as they will be noticeably different from the original. One major advantage of our scheme is that it works with traditional print techniques and required no special materials. We present our results within this paper.