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 Mathematical Model for (t, n)-Threshold Visual Cryptography Scheme

Abstract: As technology is progressing and more and more personal data is digitized, there is even more need for data security today than there has ever been. Protecting this critical data in a secure way against the unauthorised access is an immensely difficult and complicated research problem. Within the cryptographic community, many attempts have been in this regard. In visual cryptography, secret sharing offers a similar scheme, where a secret S, encoded into an image is shared among a group of n members, each of them holds a portion of the secret as their secret shares. The secret can only be retrieved when a certain number of t members (where t ≤ n) combine their shares together. And while any combination with fewer than t shares have no extra information about the secret than 0 shares. This kind of secret sharing system is known as (t, n) threshold scheme or t-out-of-n VC scheme. In this paper, we discuss various types of visual cryptographic schemes emphasizing on improving the efficiency and capacity of the original schemes. An analysis on the optimal contrast of the recovered secret, the robustness and security issues of technique is also presented. This paper attempts to develop a mathematical model based on interpolation for visual cryptography. Such a model using Lagrange’s formula is implemented and experimental results are verified. Keywords—Threshold scheme, Visual Cryptography, Mathematical Model, Lagrange Interpolation

Visual Cryptography Survey

Abstract: Cryptography is a process of transforming original information into a format such that it is only read by the desired recipient. It is used to protect information from other people for security purpose. Visual cryptography is a method which is used to encrypt information in any format like text, image, led display such that decryption is done by human eye. It does not require any key for decryption. Visual cryptography is mainly of two types segment based visual cryptography, pixel based visual cryptography. Initially this method was developed only for monochrome images then it was upgraded to grey level and then coloured images. As it does not require any key to decrypt that is why this method is unbreakable. This method is useful in vast applications which handle high value assets. It can replace the second factor that is token or key in multifactor authentication system. It can be used in online shopping sites, online banking sites, government sites. This paper gives detailed survey of visual cryptography methods and their applications.

Cancelable Biometric Template Security Using Segment-Based Visual Cryptography

Abstract: The cancelable biometric system is susceptible to a variety of attacks aimed at deteriorating the integrity of the authentication procedure. These attacks are intended to either ruin the security afforded by the system or deter the normal functioning of the authentication system. This paper describes various threats that can be encountered by a cancelable biometric system. It specifically focuses on preventing the attacks designed to extract information about the transformed biometric data of an individual, from the template database. Furthermore, we provide experimental results pertaining to a system combining the cancelable biometrics with segment-based visual cryptography, which converts traditional biocode into novel structures called shares.

Lossless Tagged Visual Cryptography Scheme Using Bit Plane Slicing for Image Processing

Abstract: Picture steganography is an evolving area of study used for safe information masking and communication over web. The projected scheme gives the path for Least Significant Bit (LSB) based steganography method alongside through Visual Cryptography. Novel information is transformed into encrypted text with the help of undisclosed key then secreted into the LSB of the authentic picture. Using visual cryptography security is increased. Shifting algorithm is used to alter the pixel place of stego image so that the discovery of this message becomes difficult. Visual data is encrypted using visual cryptography. It is achieved with dividing the representation into two shares based on a threshold. The presentation of the projected system is experimented via doing stego investigation, conducting benchmarking test for analyzing the parameters similar to Peak Signal to Noise Ratio (PSNR) and Mean Squared Error (MSE). The major aspire of this proposal is to create the improved safe algorithm which uses both steganography using Visual Cryptography to guarantee superior security and reliability.

An Improved Visual Cryptography Scheme for Colour Images

Abstract: With the growth of digital media, it is becoming more prevalent to find a method to protect the security of that media. An effective method for securely transmitting images is found in the field of Visual Cryptography (VC). Visual cryptography scheme is a cryptographic technique which allows visual information (e.g. printed text, handwritten notes, and images etc) to be encrypted in such a way that the decryption can be performed by the human visual system(HVS), without the aid of computers. The shares are safe because separately they reveal nothing about the secret image. A distinctive property of visual cryptography scheme is that one can visually decode the secret image by superimposing shares .By taking advantage of this property, third person can easily retrieve the secret image if shares are passing in sequence over the network. This paper presents a visual cryptographic technique for color images in which the generated shares are again encrypted. For this XOR operation is used and this will provide double security for the secret document. Thus secret shares are not available in their actual form for any alteration by the adversaries who try to create fake shares. The proposed scheme also uses the concept of halftoning.