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Visual cryptography

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


Papers
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Journal ArticleDOI
TL;DR: In this article, the authors analyzed the contrast of the reconstructed image in k out of n visual cryptography schemes and gave a complete characterization of schemes having optimal contrast and minimum pixel expansion in terms of certain balanced incomplete block designs.
Abstract: A visual cryptography scheme is a method to encode a secret image SI into shadow images called shares such that certain qualified subsets of shares enable the ``visual'' recovery of the secret image. The ``visual'' recovery consists of xeroxing the shares onto transparencies, and then stacking them. The shares of a qualified set will reveal the secret image without any cryptographic computation. In this paper we analyze the contrast of the reconstructed image in k out of n visual cryptography schemes. (In such a scheme any k shares will reveal the image, but no set of k-1 shares gives any information about the image.) In the case of 2 out of n threshold schemes we give a complete characterization of schemes having optimal contrast and minimum pixel expansion in terms of certain balanced incomplete block designs. In the case of k out of n threshold schemes with $k\geq 3$ we obtain upper and lower bounds on the optimal contrast.

224 citations

Journal ArticleDOI
TL;DR: This paper proposes a visual secret sharing scheme that encodes a set of x≥2 secrets into two circle shares such that none of any single share leaks the secrets and the x secrets can be obtained one by one by stacking the first share and the rotated second shares with x different rotation angles.

222 citations

Journal ArticleDOI
TL;DR: This paper defines and analyzes visual cryptography schemes for grey level images whose pixels have g grey levels ranging from 0 (representing a white pixel) to g 1 (Representing a black pixel) and gives a necessary and sufficient condition for such schemes to exist.

208 citations

Journal ArticleDOI
TL;DR: This paper proposes a generalization of the model proposed by Yang, and proves that there is a one-to-one mapping between deterministic schemes and probabilistic schemes with no pixel expansion, where contrast is traded for the probability factor.
Abstract: Visual cryptography schemes allow the encoding of a secret image, consisting of black or white pixels, into n shares which are distributed to the participants. The shares are such that only qualified subsets of participants can 'visually' recover the secret image. The secret pixels are shared with techniques that subdivide each secret pixel into a certain number m, m ≥ 2 of subpixels. Such a parameter m is called pixel expansion. Recently Yang introduced a probabilistic model. In such a model the pixel expansion m is 1, that is, there is no pixel expansion. The reconstruction of the image however is probabilistic, meaning that a secret pixel will be correctly reconstructed only with a certain probability. In this paper we propose a generalization of the model proposed by Yang. In our model we fix the pixel expansion m ≥ 1 that can be tolerated and we consider probabilistic schemes attaining such a pixel expansion. For m = 1 our model reduces to the one of Yang. For big enough values of m, for which a deterministic scheme exists, our model reduces to the classical deterministic model. We show that between these two extremes one can trade the probability factor of the scheme with the pixel expansion. Moreover, we prove that there is a one-to-one mapping between deterministic schemes and probabilistic schemes with no pixel expansion, where contrast is traded for the probability factor.

208 citations

Journal ArticleDOI
TL;DR: A threshold RG-based VSS scheme aiming at providing the wide-use version is presented, and the experimental results and theoretically analysis in visual quality and security show that the proposed scheme performs well.

203 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202334
202291
202158
202064
201982
2018132