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 Efficient Anti Phishing Method Based on Visual Cryptography Using Cloud Technique By Smart Phones

Abstract: Phishing is nothing but an attempt made by an individual or group to thieve personal confidential information such as password, credit card information, Transaction Number etc. from unsuspecting victims for identity theft and fraudulent activities. Since the importance of smart phones is increased day to day as more applications are deployed and executed. In this paper, a new approach named as "An Efficient Anti phishing method based on Visual Cryptography using cloud technique by smart phones" to solve the problem of phishing. The visual cryptography is explored to preserve the privacy image Captcha by decomposing it into two shares that are stored in cloud (data severs) such that, when original Captcha can be revealed when the both are available at same time. Since users are unable to carry the Captcha place to place so a concept of Image Captcha conversion into String with the help of cloud is revealed which can be used as the password.

An EVCS for Color Images with Real Size Image Recovery and Ideal Contrast Using Bit Plane Encoding

Abstract: Conventional visual secret sharing schemes generate noise-like random pixels on shares to hide secret images. It suffers a management problem, because of which dealers cannot visually identify each share. This problem is solved by the Extended Visual Cryptography scheme (EVCS). However, the previous approaches involving the EVCS for general access structures suffer from a low contrast problem. This paper proposes a new (k,n)-threshold image sharing scheme using extended visual cryptography scheme for color images based on bit plane encoding that encrypts a color image in such a way that results of encryption is in the form of shares. Shares do not reflect any information directly, information is scrambled instead. The traditional binary EVCS is used to get the sharing images at every bit level of each principle component of a color image. This scheme provides a more efficient way to hide natural images in different shares. Furthermore, the size of the hidden secret can be recovered by inspecting the blocks in the shares. This new scheme for color images gives the ideal contrast in the recovered image.

Stokes meta-hologram toward optical cryptography

Abstract: Optical cryptography manifests itself a powerful platform for information security, which involves encrypting secret images into visual patterns. Recently, encryption schemes demonstrated on metasurface platform have revolutionized optical cryptography, as the versatile design concept allows for unrestrained creativity. Despite rapid progresses, most efforts focus on the functionalities of cryptography rather than addressing performance issues, such as deep security, information capacity, and reconstruction quality. Here, we develop an optical encryption scheme by integrating visual cryptography with metasurface-assisted pattern masking, referred to as Stokes meta-hologram. Based on spatially structured polarization pattern masking, Stokes meta-hologram allows multichannel vectorial encryption to mask multiple secret images into unrecognizable visual patterns, and retrieve them following Stokes vector analysis. Further, an asymmetric encryption scheme based on Stokes vector rotation transformation is proposed to settle the inherent problem of the need to share the key in symmetric encryption. Our results show that Stokes meta-hologram can achieve optical cryptography with effectively improved security, and thereby paves a promising pathway toward optical and quantum security, optical communications, and anticounterfeiting.